The experiment was designed as a radiosensitivity test, a foundational step in mutation breeding programs. Before plant breeders can use gamma irradiation to generate genetic variation, they must establish which doses stress plants enough to induce mutations without wiping out the population entirely. The research team irradiated strawberry plants and measured a suite of traits including survival rate, leaf area, leaf fresh and dry weight, root length, and flower number across the full dose range. This systematic approach allowed them to construct a quantitative profile of how strawberry responds as radiation exposure climbs.

The sweet spot turned out to be remarkably low on the dose scale. At 30 gray, plants achieved the highest leaf area of any treatment group, produced an average of 16.66 flowers per plant, extended their roots to a maximum length of 20.66 centimeters, and accumulated the greatest leaf fresh and dry weights, at 2.69 grams and 0.83 grams respectively. These plants outperformed even the untreated controls on several measures, a pattern the researchers suggest may reflect a phenomenon known as hormesis, in which low doses of an otherwise harmful agent stimulate biological activity rather than suppress it.

Hormesis remains one of the more intriguing concepts in radiation biology. The idea is that a small stressor can trigger repair mechanisms and physiological responses that leave an organism better off than before. In plants, low-dose radiation has occasionally been linked to enhanced germination, increased enzyme activity, and stimulated growth, though the underlying mechanisms are still debated. The strawberry findings add a horticulturally relevant data point: whatever the mechanism, the 30 gray treatment did not merely spare the plants but appeared to actively boost their vegetative and flowering traits.

Beyond that optimum, the picture darkened quickly. Doses of 60 gray and above markedly reduced survival and dragged down most growth and reproductive parameters. At the harshest exposures of 80 to 100 gray, the effects were severe, with plants struggling to survive and showing dramatic losses across the measured traits. The dose-response curve that emerged is steep, illustrating how quickly the balance tips from stimulation to damage as absorbed dose increases. High-energy gamma rays break DNA strands and generate reactive oxygen species within cells, and once the damage load exceeds repair capacity, growth collapses.

To make the results practically useful, the team calculated lethal dose benchmarks, the radiation levels at which 25, 50, and 75 percent of plants would be expected to die. These came out at 28.05 gray for LD25, 52.53 gray for LD50, and 77.01 gray for LD75. Such values are the currency of mutation breeding. Breeders typically aim for doses that kill roughly a third to half of the treated material, enough to ensure mutagenic damage in survivors while keeping a viable population for selection. The newly established radiosensitivity profile gives strawberry breeders a quantitative map for choosing doses in future experiments rather than relying on trial and error.

The study also identifies candidate doses for the next phase of research. The authors note that doses above 50 gray, while harmful to plant performance, are the levels most likely to generate heritable genetic variation, which is the raw material mutation breeding depends on. Any promising variants would still need confirmation that their altered traits are genetically stable and transmissible rather than temporary physiological responses. The researchers are explicit on this point, stating that higher doses qualify as potential candidates pending confirmation of heritable variation.

Strawberry is a high-value crop with a complex genome, and improvement programs constantly seek new sources of variation for traits such as fruit quality, disease resistance, and flowering behavior. Conventional crossbreeding is complicated by the plant’s octoploid genetics in many cultivated species and by the clonal propagation methods that preserve elite varieties but limit genetic reshuffling. Induced mutation offers a shortcut, allowing breeders to nudge the genome of an already successful cultivar without introducing foreign germplasm. Determining the correct irradiation dose, as this study does, is the gatekeeping step that determines whether such programs succeed.

The research was carried out by Ali Akbar Ghasemi-Soloklui, Saeed Moori, and Mojtaba Kordrostami of the Nuclear Agriculture Research School at the Nuclear Science and Technology Research Institute in Karaj, along with Masoud Shahmoradi of the Department of Horticultural Science at Shiraz University. The team stresses that the moderate 30 gray dose produced the most favorable growth, root development, and flowering responses, a finding they interpret as evidence of a possible hermetic, or hormetic, effect in strawberry. The work received no external funding, and the authors declare no competing interests.

For growers and breeders alike, the study delivers a clear practical message: in the world of gamma irradiation, more is definitely not better. A carefully calibrated dose near 30 gray can coax strawberry plants into more vigorous vegetative growth and more abundant flowering, while anything approaching the lethal benchmarks risks losing the crop altogether. As the team moves toward mutation-breeding trials with higher candidate doses, the strawberry industry may soon see whether radiation-induced variation can translate these greenhouse-scale responses into new varieties with traits worth savoring.

Subject of Research: Dose-dependent effects of gamma irradiation on strawberry plant growth and reproductive traits

Article Title: Dose-dependent effects of gamma irradiation on growth and reproductive traits of strawberry

Article References: Ghasemi-Soloklui, A. A., Moori, S., Kordrostami, M., & Shahmoradi, M. (2026). Dose-dependent effects of gamma irradiation on growth and reproductive traits of strawberry. BMC Plant Biology, 26(1), Article 1675. https://doi.org/10.1186/s12870-026-09912-w

Image Credits: AI Generated

DOI: 10.1186/s12870-026-09912-w

Keywords: strawberry, gamma irradiation, mutation breeding, radiosensitivity, hormesis, plant biology, flowering, LD50, radiation dose, vegetative growth, reproductive traits, BMC Plant Biology

The research, carried out at Hawassa University and published in BMC Plant Biology, was led by Alemu Bade Anchiwe and colleagues at Wolkite University and Hawassa University. The team exposed vine cuttings of three sweet potato genotypes to gamma radiation from a cobalt-60 source and then tracked how the first vegetative generation, designated M1V1, grew, photosynthesized, accumulated protective compounds and fared against virus infection over 150 days after planting. The work was conducted in a screen house using a randomized complete block design with 20 replications, a robust statistical layout that helps separate genuine treatment effects from environmental noise.

The three genotypes were chosen to represent different flesh colors and market profiles. Hawassa-83 is a white-fleshed variety, Alamura has orange flesh rich in beta-carotene, and Kabode carries a creamy yellow flesh color. Each was irradiated at four doses: zero as a control, and 15, 25 and 35 gray, the unit that measures absorbed radiation energy. The doses were deliberately low by industrial standards, because the goal was not to destroy the plants but to nudge their genomes into producing new combinations of traits while keeping enough of the population alive for selection.

A central question in any mutation breeding program is radiosensitivity: how much radiation a genotype can absorb before half of the individuals die or fail to grow. The researchers determined this threshold using probit analysis, a statistical technique that models dose-response relationships for binary outcomes such as survival. The results revealed striking genotype-dependent differences. Alamura proved the most radio-tolerant, with a median lethal dose, or LD50, of 39.51 gray and a dose producing 50 percent growth reduction, or GR50, of 37.56 gray. Kabode was the most sensitive, with an LD50 of 32.58 gray and a GR50 of 32.49 gray. These numbers matter practically, because they tell breeders the optimal irradiation window for each variety: too low and few mutations appear, too high and the population collapses before useful variants can be recovered.

Beyond survival, the study documented significant main effects and interactions between genotype and radiation dose across a suite of agronomic and physiological traits, all statistically significant at the five percent level. One of the most intriguing findings was evidence of hormesis, the phenomenon in which a stressor that is harmful at high doses produces a stimulatory effect at low doses. Tuber production followed this pattern clearly. Hawassa-83 reached its peak productivity at 25 gray, producing 6.94 tubers per plant, a 33 percent increase over the untreated control. Alamura also peaked at 25 gray with 6.35 tubers. In other words, a moderate blast of radiation actually made the plants more productive, not less.

The nutritional payoff was equally striking. At 25 gray, the beta-carotene content of Alamura tubers increased by 68.6 percent, reaching 11 milligrams per 100 grams. Beta-carotene is the pigment that gives orange-fleshed sweet potatoes their color and the precursor from which the human body synthesizes vitamin A. In regions where sweet potato is a dietary staple and vitamin A deficiency remains a serious public health problem, a mutation that boosts provitamin A content by more than two-thirds could have meaningful nutritional consequences, particularly for children and pregnant women who are most vulnerable to deficiency.

Virus disease posed the other major challenge the breeders set out to address. Sweet potato virus disease, caused by complexes of viruses that can devastate yields across Africa, was scored as virus disease severity, or VDS, across the growth stages. Untreated plants showed baseline severity scores between 3.2 and 3.6, indicating substantial infection. At the highest dose of 35 gray, however, severity dropped dramatically to 1.15 in Alamura and 1.37 in Hawassa-83, scores corresponding to highly resistant reactions. The suppression of viral symptoms correlated directly with the plants’ morpho-physiological condition, suggesting that radiation-induced changes in the plant’s internal state contributed to the resistance phenotype rather than the effect being a random artifact.

Two physiological measurements helped explain what was happening inside the irradiated plants. The first was chlorophyll fluorescence, specifically the Fv/Fm ratio, which quantifies the maximum quantum efficiency of photosystem II and is a standard indicator of photosynthetic health. Alamura maintained a high Fv/Fm value of 0.78 at 25 gray, close to the theoretical optimum for unstressed plants, before suffering severe photoinhibition at 35 gray. The second was proline, an amino acid that accumulates in plants under stress and acts as an osmoprotectant and antioxidant. Proline peaked at 25 gray in both Alamura, at 10.35 micromoles per gram, and Hawassa-83, at 8.3 micromoles per gram. The coincidence of peak proline accumulation, high photosynthetic efficiency and maximal virus suppression at the intermediate dose suggests a coherent physiological signature of the most beneficial treatment level.

To make sense of the many measured traits, the team turned to multivariate statistics. Correlation analysis, principal component analysis and hierarchical cluster analysis were applied to the full dataset, and these tools effectively isolated multi-trait putative mutant lines, plants that combined favorable changes across yield, nutrition and disease resistance rather than excelling in only one dimension. From the irradiated cohorts, the researchers identified three promising multi-trait putative M1V1 mutant clones: one each from the Alamura lines treated at 15 and 25 gray, and one from the Hawassa-83 cohort treated at 25 gray. Each showed concurrent enhancements in tuber yield, beta-carotene content and virus resistance, a combination that would be extremely difficult to achieve through conventional crossing in this crop.

The authors caution that these are putative mutants from the first vegetative generation, and further generational advancement will be needed to confirm that the enhanced traits are stable and heritable rather than transient physiological responses. Even so, the study establishes precise selection targets for sweet potato mutation breeding and demonstrates that the approach can deliver on all three fronts the breeders prioritized: resistance to viral disease, improved nutritional quality and high yield. The research was supported by the International Atomic Energy Agency through its Coordinated Research Project D24014, and the radiation source was provided by the Animal Health Institute’s Tsetsefly Efficiency Center. For a crop on which millions of smallholder farmers depend, the finding that a carefully calibrated dose of gamma radiation can push yield up by a third, provitamin A up by more than two-thirds and virus severity down to resistant levels offers a compelling, and remarkably efficient, new tool for food security breeding programs.

Subject of Research: Gamma irradiation-induced mutation breeding of sweet potato for yield, beta-carotene content and virus resistance

Article Title: Radiosensitivity and early-stage morpho-physiological profiling of M1V1 sweet potato (Ipomoea batatas L.) vine cuttings to different doses of gamma irradiation: breeding for mutants with virus resistance, nutritional quality, and high yield

Article References: Anchiwe, A. B., Buko, D. H., Terfa, M. T., & Roro, A. G. (2026). Radiosensitivity and early-stage morpho-physiological profiling of M1V1 sweet potato (Ipomoea batatas L.) vine cuttings to different doses of gamma irradiation: breeding for mutants with virus resistance, nutritional quality, and high yield. BMC Plant Biology. https://doi.org/10.1186/s12870-026-09919-3

Image Credits: AI Generated

DOI: 10.1186/s12870-026-09919-3

Keywords: sweet potato, gamma irradiation, mutation breeding, radiosensitivity, hormesis, beta-carotene, virus resistance, chlorophyll fluorescence, proline, Ipomoea batatas, M1V1 generation, multivariate analysis

The challenge the researchers set out to solve is one of the most stubborn in crop breeding. Introducing salinity tolerance into an adopted, farmer-favorite variety usually means crossing it with a tolerant donor and then spending years backcrossing to recover the original grain quality, often with mixed results. Mutation breeding offers a shortcut: bombard seeds with radiation, let the plants grow, and select individuals whose randomly mutated genes happen to confer stress tolerance. The risk is collateral damage, since radiation mutates the entire genome indiscriminately, potentially degrading the very traits that made the variety popular in the first place.

To generate the mutant population, the team treated Satabdi seeds with 300, 400, and 500 Gy doses of gamma rays, then advanced the surviving plants through successive generations to stabilize the mutations. By the fourth mutant generation, or M4, they had roughly 500 lines to work with. Screening at the seedling stage under salinity stress identified eight tolerant lines, designated SM-1 through SM-8, and the researchers confirmed that this tolerance persisted through the sixth mutant generation, ruling out chance environmental effects.

What makes the results technically striking is the physiological mechanism behind the tolerance. Under salt stress, the tolerant mutants accumulated significantly lower sodium ion concentrations in their shoots while maintaining higher potassium levels, resulting in lower sodium-to-potassium ratios than the parent Satabdi. This ion discrimination is the hallmark of effective salinity tolerance in rice, since excess sodium disrupts enzyme function and photosynthesis while potassium is essential for cellular processes. Lines SM-1, SM-6, and SM-8 scored a tolerance rating of 3 on the standard SES scale, indicating strong tolerance, while the remaining lines ranged from moderately tolerant to tolerant.

The researchers did not stop at the seedling stage, which is where many salinity studies end. They also evaluated the mutants under salinity stress at the reproductive stage, when the plant is forming grain and yield losses are most economically painful. Here the difference was dramatic: while Satabdi suffered a severe yield penalty with a yield stability index of just 0.22, the mutant lines maintained indices between 0.43 and 0.56, meaning they lost roughly half as much yield under salt stress. This dual-stage tolerance is rare and valuable, since tolerance at one life stage often does not translate to the other.

Perhaps the most important finding for farmers and consumers is what did not change. Using the standard DUS descriptors for distinctiveness, uniformity, and stability, the researchers found that all eight mutant lines were morphologically identical to Satabdi in every measured character except panicle length. Grain physicochemical analysis confirmed that the premium long-slender grain quality of the parent was largely retained across the mutants. For a variety whose market value depends on grain appearance and cooking properties, this preservation is the difference between a useful breeding product and an academic curiosity.

Molecular genotyping with trait-specific SNP markers confirmed the visual assessment. SM-1 and SM-3 retained approximately 96 percent of the Satabdi genome, meaning the radiation had introduced only a small number of targeted changes rather than scrambling the whole genome. Lines SM-2 and SM-8, which showed tolerance at both seedling and reproductive stages, carried higher numbers of mutated favorable alleles for stress tolerance, suggesting the radiation had hit multiple genes involved in salt response simultaneously.

The implications for coastal rice-growing regions, particularly in eastern India where Satabdi is widely grown, are significant. Salinity intrusion from rising seas and cyclone-driven storm surges is an escalating threat to rice productivity in these areas, and farmers there face a difficult choice between adopting tolerant varieties with unfamiliar grain quality or sticking with preferred varieties that fail under salt stress. Mutant lines derived from Satabdi could offer a third path: the same variety farmers already know and trust, but engineered through radiation to withstand the salt that increasingly threatens their fields.

The study also demonstrates the broader value of mutation breeding as a complement to conventional hybridization. While transgenic approaches and marker-assisted backcrossing have produced salt-tolerant rice lines, they face regulatory hurdles and require extensive breeding cycles. Gamma-ray mutagenesis, by contrast, generates genetic variation without introducing foreign DNA, and the resulting mutants can be deployed more rapidly. The researchers note that their work confirms gamma-ray-induced mutagenesis can generate promising salinity-tolerant lines that retain the parent’s agronomic and grain-quality traits, offering potential for deployment in coastal saline rice-growing areas.

What remains to be seen is how these mutants perform in multi-location field trials across diverse coastal environments and whether the tolerance holds up under the combined stresses of salinity, flooding, and temperature extremes that characterize real-world conditions. But the core result stands: eight lines, derived from a single premium variety through radiation alone, that survive salt stress at both seedling and reproductive stages while remaining genetically and morphologically nearly indistinguishable from the parent. For the millions of rice farmers on the front lines of soil salinization, that combination of tolerance and trait preservation may prove to be exactly what they need.

Subject of Research: Gamma-ray mutagenesis of the premium rice variety Satabdi to develop salinity-tolerant mutant lines retaining grain quality

Article Title: Integrative Phenotypic, Agro-morphological, Grain Physicochemical, and Molecular Characterization of Salinity-Tolerant Mutants Derived from the Premium Rice Variety Satabdi

Article References: Chattopadhyay, K., Molla, K. A., Anilkumar, C., Das, M. P., Preethi, B., Mohapatra, S. S., Dehury, P., Bagchi, T. B., Sarkar, S., Marndi, B. C., & Chakraborty, K. (2026). Integrative Phenotypic, Agro-morphological, Grain Physicochemical, and Molecular Characterization of Salinity-Tolerant Mutants Derived from the Premium Rice Variety Satabdi. Indian Journal of Genetics and Plant Breeding. https://doi.org/10.1007/s44489-026-00054-9

Image Credits: AI Generated

DOI: 10.1007/s44489-026-00054-9

Keywords: rice, salinity tolerance, gamma-ray mutagenesis, mutation breeding, Satabdi, grain quality, SNP genotyping, sodium-potassium ratio, coastal agriculture, crop yield stability, India, plant genetics

The team, led by Sanjeev Kumar of Sher-e-Kashmir University of Agricultural Sciences and Technology of Jammu, with collaborators from the Bhabha Atomic Research Centre in Mumbai and ICRISAT in Hyderabad, began with a high-yielding but cold-susceptible variety called GNG1958, released for India’s northwestern plain zone. Seeds were irradiated at the Bhabha Atomic Research Centre with gamma rays at doses of 250, 300, 350, 400, and 450 gray. Pivotal analysis identified two key doses—254.90 gray, slightly below the lethal dose for 50 percent of seeds, and 335.74 gray, the lethal dose itself—and 500 seeds were treated at each level.

From those irradiated seeds, the researchers developed 257 mutant lines in the second generation, or M2, comprising 100 lines from the lower dose and 157 from the higher one. These were sown in November 2023 at the university’s experimental farm, located at 32.68 degrees north latitude and 281 meters above sea level, where winter conditions are ideal for cold screening. Alongside the mutants, the team planted three reference lines: the untreated control GNG1958, the nationally susceptible check ICC12968, and the nationally cold-tolerant check ICC92944. Field data were recorded from 25 plants per mutant, while laboratory analyses of electrolyte leakage, chlorophyll, and carotenoids used samples from 10 plants each.

The screening protocol was deliberately harsh. Plants were only evaluated for cold tolerance after the susceptible check ICC12968 had died in the field, ensuring that the surviving mutants had faced genuinely lethal temperatures. Electrolyte leakage index, a measure of membrane damage, was calculated by measuring the electrical conductivity of leaf tissue soaked in deionized water, then again after autoclaving at 120 degrees Celsius to destroy all cells. The ratio between the two readings reveals how much of the cell’s internal electrolytes had already leaked out through damaged membranes—a lower percentage means the membrane stayed intact under cold stress.

Chlorophyll and carotenoid pigments were extracted using dimethyl sulphoxide and quantified by spectrophotometry at 665, 645, and 454 nanometers, following established equations for chlorophyll a, chlorophyll b, and carotenoids. In the field, each mutant was scored on a cold tolerance rating scale from 1 to 9, where 1 means no damage and 9 means most seedlings dead or dying. A frost resistance ratio was also calculated by dividing the number of plants surviving at harvest by the number present after emergence but before the first frost, with values approaching 1 indicating resistance.

Across two growing seasons—the Rabi seasons of 2023–24 and 2024–25—the pooled data revealed 50 promising cold-tolerant mutants. Of these, 26 showed electrolyte leakage below 10 percent combined with carotenoid content above 0.50 milligrams per gram of fresh weight, a combination the authors interpret as resistance to cold stress at the vegetative stage during periods of high cold. Three mutants stood out as highly promising: 335.74 Gy-Ch-M-45 with an electrolyte leakage index of just 6.79 percent, total chlorophyll of 2.48 milligrams per gram, and a seed yield of 48.78 grams per plant; 335.74 Gy-Ch-M-155 with leakage of 7.24 percent and the highest yield among the three at 59.22 grams per plant; and 335.74 Gy-Ch-M-66 with leakage of 7.30 percent and chlorophyll of 2.49 milligrams per gram.

For comparison, the susceptible check ICC12968 recorded an electrolyte leakage of 42.77 percent and a cold tolerance rating of 6, meaning it succumbed to cold injury in the field. The control GNG1958 leaked 31.23 percent and scored 4 on the rating scale, while the national tolerant check ICC92944 leaked 25.94 percent and scored 2.50. Against these benchmarks, the elite mutants performed dramatically better, with several showing cold tolerance ratings of 1.0 to 1.5—scores indicating essentially no visible damage—while simultaneously maintaining higher chlorophyll and carotenoid levels than the parent variety.

Correlation analysis revealed a tight relationship between membrane integrity and visible cold damage: the electrolyte leakage index and the cold tolerance rating were positively correlated with a coefficient of 0.87, significant at the 1 percent level. Seed yield correlated positively with total chlorophyll, carotenoid content, and frost resistance ratio, but negatively with electrolyte leakage and cold tolerance rating. In practical terms, mutants that kept their membranes sealed and their pigments intact also produced more seed—a coherent physiological signature of cold tolerance rather than a coincidence of unrelated traits.

Biochemical profiling of the top 15 mutants in the third generation added another layer. Proline, an osmoprotectant that stabilizes proteins and membranes under stress, ranged from 0.90 to 3.44 micromoles per gram of fresh weight, with mutant 335.74 Gy-Ch-M-153 accumulating the most. Sugar content, measured by the anthrone method, ranged from 6.64 to 46.16 milligrams per gram, with 335.74 Gy-Ch-M-45 and 335.74 Gy-Ch-M-65 exceeding even the cold-tolerant check. Protein percentage, estimated non-destructively by near-infrared spectroscopy, varied narrowly between 21.26 and 23.08 percent. Two mutants in particular—254.90 Gy-Ch-M-01 and 254.90 Gy-Ch-M-32—showed higher sugar, proline, and protein content than the control along with superior values on eight and nine cold tolerance parameters respectively, plus higher seed yield.

Genetic analysis of the mutant population revealed that heritability was high for all traits but genetic advance was low, except for seed yield, where high heritability paired with high genetic advance indicated additive gene action amenable to selection. For the cold tolerance traits themselves, the pattern of high heritability with low genetic advance pointed to non-additive gene action—epistasis, dominance, and gene-by-environment interaction—meaning direct selection on those traits alone would yield disappointing gains. The authors suggest that the wide variation in seed yield among mutants may reflect stable gene mutations that will persist in subsequent generations, making yield itself the more reliable selection target.

The broader context makes the finding significant. Chickpea is the second most important cool-season food legume in the world after dry beans, and India is its largest producer, consumer, and importer. Yet productivity hovers around one ton per hectare, constrained by biotic and abiotic stresses. Cold is a particularly costly problem: winter-sown chickpea in northern South Asia and parts of Australia faces temperatures between 0 and 15 degrees Celsius during the reproductive stage, causing flower and pod loss and reducing yield potential by 30 to 40 percent. Economic losses from cold in chickpea have been estimated at 186 million US dollars, compared to 1.3 billion from drought and heat and 354 million from salinity. Climate change may intensify cold spells in temperate regions, making cold-resilient cultivars more urgent, not less.

Mutation breeding offers a way forward precisely because cultivated chickpea has a narrow genetic base. Unlike wide crosses with wild relatives, mutagenesis can be applied directly to elite cultivars without dragging along unwanted linked traits. India has a long history with the technique—the first micro-mutant chickpea varieties in the world were developed at the Indian Agricultural Research Institute in New Delhi and released in 1985 following gamma irradiation. The new mutants from Jammu join that lineage, and the authors propose them as donor parents for introgressing cold tolerance into well-adapted varieties, as parental genotypes for mapping populations, and as subjects for differential gene expression studies aimed at identifying the genes underlying cold tolerance.

What makes the work notable is the multi-year, multi-generation discipline behind it. Rather than declaring victory after one season, the team carried 217 of the original 257 mutants into a second winter, re-screened them in the M3 generation, and only then shortlisted 50 putative mutants and, from those, 15 elite lines based on pooled mean performance across both years and both field and laboratory traits. The 15 top performers—including 254.90 Gy-Ch-M-01, 254.90 Gy-Ch-M-09 with a yield of 74.20 grams per plant, and 335.74 Gy-Ch-M-140 at 72.69 grams per plant—were stable across generations, which is exactly what a breeding program needs from a donor parent.

The study was funded by the Board of Research in Nuclear Sciences of the Government of India, grant number 3758, reflecting the institutional partnership between the agricultural university and the Bhabha Atomic Research Centre that made the irradiation work possible. As climate variability tightens its grip on subtropical agriculture, the Jammu mutants offer a concrete, field-validated resource: lines that have already survived the coldest nights the northwestern Himalayas can deliver, and that carry the physiological and biochemical machinery to keep photosynthesis running, membranes sealed, and seeds filling when the temperature drops. For breeders worldwide trying to push chickpea yields upward against a backdrop of increasingly erratic weather, these gamma-induced lines may prove to be exactly the genetic raw material they have been looking for.

Subject of Research: Gamma-induced cold-tolerant chickpea mutants screened across physiological, biochemical, and agronomic traits in northwestern India

Article Title: Characterization of physiological, biochemical, and agronomical traits of elite induced chickpea mutants from the northwestern Himalayan region of the UT of J & K, India

Article References: Kumar, S., Saha, A. J., Padha, R., Chand, G., Kashyap, S. C., Srivastava, R. K., Singh, A. K., & Mahajan, A. (2026). Characterization of physiological, biochemical, and agronomical traits of elite induced chickpea mutants from the northwestern Himalayan region of the UT of J & K, India. Frontiers in Plant Physiology, 4, Article 1766618. https://doi.org/10.3389/fphgy.2026.1766618

Image Credits: AI Generated

DOI: 10.3389/fphgy.2026.1766618

Keywords: chickpea, cold stress, mutation breeding, gamma irradiation, electrolyte leakage, chlorophyll, carotenoids, proline, frost resistance, seed yield, Cicer arietinum, plant physiology

Researchers Esther Dankwah, Isaac Kojo Asante, and Prince Asiedu treated seeds of the Ghanaian cowpea variety Wankae with different concentrations of ethyl methane sulfonate, or EMS, an alkylating agent widely used in plant mutation breeding. Their work, published in Discover Plants, evaluated germination, survival, and a broad suite of morphological and agronomic traits in the first mutagenized generation, known as the M1. The choice of EMS was deliberate: unlike genome editing or marker-assisted selection, which demand substantial infrastructure and technical expertise, chemical mutagenesis offers a low-cost route to novel variation that is accessible to breeding programs with limited resources. Since the pioneering discoveries of Muller and Stadler in the late 1920s, induced mutation has generated roughly 3,500 released varieties worldwide, most of them food crops, yet no cowpea mutant variety has been developed through mutagenesis in Sub-Saharan Africa.

The experimental design was straightforward but rigorous. One hundred uniform, healthy seeds were divided into four treatment groups of twenty-five, exposed to EMS concentrations of 0, 20, 60, and 80 millimolar, selected on the basis of previous cowpea mutagenesis studies. Seeds were pre-soaked in distilled water for twelve hours to activate metabolic processes, then treated with EMS for a further twelve hours at room temperature before thorough rinsing and sowing in potting bags under a completely randomized design at the University of Ghana’s Legon campus. Germination was scored seven days after sowing, survival at flowering, and the surviving plants were characterized using International Board for Plant Genetic Resources descriptors, covering both quantitative traits such as plant height, branching, and seed dimensions, and qualitative traits including growth habit, flower color, and seed coat color.

The dose-response relationship proved strikingly linear. Germination fell from 100 percent in the untreated control to 96 percent at 20 millimolar EMS and down to 88 percent at 80 millimolar, with lethal seeds rising correspondingly from zero to 12 percent. Regression analysis confirmed a significant negative relationship between EMS concentration and germination, with the linear model explaining 98 percent of the variation in germination percentage; a quadratic model offered no evidence of curvature and was rejected as less parsimonious. The mean time to 50 percent germination lengthened from 2.60 days in the control to 4.14 days at the highest dose, reflecting the accumulating DNA damage that impairs replication, repair, and meristematic activity in embryonic tissues. Survival, by contrast, remained remarkably high across all treatments, ranging from 95.45 to 100 percent, indicating that the doses chosen induced variation while still leaving enough plants for meaningful evaluation.

The most commercially intriguing result was the pattern of enhancement at moderate doses. At 20 millimolar EMS, treated plants outperformed the control across a series of agronomically important traits: mean plant height reached 34.66 centimeters, main branches averaged 5.46 per plant, peduncle length extended to 15.12 centimeters, pods per plant rose to 14.39, locules per pod climbed to 12.09, and average seed weight reached 5.01 grams. Some individual plants grew to 110 centimeters, produced stems up to 5.9 centimeters in girth, and bore as many as 11 branches. The authors attribute this stimulatory effect to hormesis, a phenomenon in which mild stress triggers physiological responses that promote development, possibly through modulation of auxin- and cytokinin-mediated pathways governing cell division, elongation, and meristem activity. Enhanced shoot apical meristem function could explain the taller stems, while stimulated axillary meristems account for the extra branching.

Reproductive traits showed their own dose-dependent dynamics. Locule number per pod increased from 8.80 in the control to 12.09 under moderate treatment before declining at higher doses, suggesting that low-level mutagenic pressure may beneficially alter genes regulating floral organ development and pod formation. Seed thickness increased among treated populations, a trait with implications for seed reserves, vigor, storage performance, and seedling establishment. Pod width and seeds per pod, however, declined at higher concentrations, dropping from 1.16 to 1.00 centimeters and from 10.22 to 7.73 respectively, consistent with excessive DNA damage disrupting the hormonal coordination required for flower and pod development. Notably, days to 50 percent flowering and days to first harvest were unaffected, meaning breeders can generate diversity without shifting crop duration, an advantage for maintaining varietal adaptation.

Perhaps the most visually dramatic findings came from the qualitative traits. The control population was entirely uniform: erect plants with determinate growth, white flowers, straw or dark tan pods, cream seed coats, and kidney-shaped seeds. EMS treatment shattered that uniformity. Purple-flowered plants appeared at low frequencies of 4.17 percent at 20 millimolar and 4.55 percent at 80 millimolar, likely reflecting mutations in anthocyanin biosynthesis or its regulatory pathways. A rare dark purple mature pod color emerged at 4.55 percent in the highest-dose population, while brown seed coats appeared at 20 millimolar and black seed coats at 80 millimolar. Seed shape diversified to include ovoid, rhomboid, and globose forms alongside the parental kidney shape, and the mutagenized populations produced climbing habits, indeterminate growth patterns, and twinning phenotypes entirely absent from the control. Because seed coat color strongly influences consumer preference and marketability of dry grain legumes, these novel color classes carry potential economic as well as scientific significance.

To separate genuine mutant candidates from ordinary variation, the team employed generalized linear model contrast analysis, classifying as putative mutants any individuals whose trait values fell outside the observed control range and were associated with statistically significant treatment effects. By this criterion, mutant phenotypes were recovered at frequencies ranging from 4.12 to 39.13 percent across developmental, reproductive, yield-related, and seed traits, with consistently low p-values indicating the differences were unlikely to arise by chance. Days to germination showed the highest mutant frequency, particularly at 80 millimolar, while expanded ranges in days to branching and days to first flowering pointed to altered developmental timing that could prove useful for maturity adaptation. Moderate doses proved especially productive for vigorous, potentially valuable phenotypes, including plants with dramatically increased height, branching, and pod number.

The broader message is one of balance. Higher EMS concentrations undeniably generate more phenotypic variability, including rare morphological alterations that lower doses never produce, but they exact a toll in reduced germination, survival, and yield traits, shrinking the pool of selectable plants and raising the selection burden. Moderate exposure, in this study 20 millimolar, appears to occupy a beneficial mutation window, inducing subtle genetic changes that modify trait expression without wrecking physiological stability. The authors caution that their evaluation was limited to the M1 generation, where observed effects may blend true heritable mutations with temporary physiological responses to mutagen exposure. Confirming stability, heritability, and breeding value will require advancing the putative mutants to the M2 generation and beyond, ideally with molecular characterization and multi-environment trials. Still, for a crop central to food security across a region where its genetic base has narrowed dangerously, the study demonstrates that a decades-old chemical tool can still deliver a fresh infusion of diversity, and it hands Ghanaian and regional breeders a concrete set of candidate mutant lines to carry forward.

Subject of Research: EMS-induced phenotypic variation in the M1 generation of cowpea

Article Title: Evaluation of EMS-induced phenotypic variation in the M1 generation of cowpea (Vigna unguiculata L. Walp.)

Article References: Dankwah, E., Asante, I. K., & Asiedu, P. (2026). Evaluation of EMS-induced phenotypic variation in the M1 generation of cowpea (Vigna unguiculata L. Walp.). Discover Plants, 3(1), Article 462. https://doi.org/10.1007/s44372-026-00939-9

Image Credits: AI Generated

DOI: 10.1007/s44372-026-00939-9

Keywords: cowpea, EMS mutagenesis, mutation breeding, phenotypic variation, M1 generation, Vigna unguiculata, germination, putative mutants, seed coat color, plant breeding, genetic diversity, Ghana

The case for intervention rests on a paradox at the heart of Bambara groundnut agriculture. The crop is remarkably well suited to marginal environments, producing reasonable yields in poor soils with limited rainfall, and it enriches the land through biological nitrogen fixation. Its seeds typically contain 15 to 25 percent protein, 50 to 65 percent carbohydrate, and appreciable levels of essential amino acids, dietary fibre, vitamins and minerals, a profile that has led researchers to describe it as a complete food. Yet despite these advantages, productivity remains constrained by low yield potential, long maturity periods, asynchronous pod development, susceptibility to environmental stresses, and a scarcity of officially released improved cultivars, particularly in countries such as Zimbabwe, Mozambique and Malawi.

Underlying these agronomic shortcomings is a genetic bottleneck. Centuries of farmer selection have maintained locally adapted landraces displaying striking diversity in seed colour, pattern, size and growth habit, but the desirable combinations of high yield, early maturity, synchronized pod development and stress tolerance are rarely found within individual genotypes. The crop’s predominantly self-pollinating nature further complicates conventional crossing, making it demanding to generate and evaluate new trait combinations. Induced mutagenesis offers a complementary route: by exposing plant material to physical or chemical mutagens, breeders can create novel heritable variation within already adapted genetic backgrounds, something conventional breeding alone cannot achieve when the needed alleles simply do not exist in the germplasm.

The technical toolkit is well established. Physical mutagens, including gamma rays, X-rays, beta rays, ion beams, electron beams and fast neutrons, damage DNA through chromosomal breaks and structural rearrangements, with gamma radiation being the most frequently used agent in Bambara groundnut owing to its high penetration ability. Chemical mutagens such as ethyl methane sulphonate, sodium azide and nitroso methyl urea instead induce point mutations by altering nucleotide sequences during DNA replication. Dose determination is critical, since excessive treatment causes physiological damage or lethality while insufficient doses fail to generate useful mutation frequencies. Studies reviewed by the authors emphasize that responses are strongly genotype-specific, underscoring the need for tailored protocols rather than one-size-fits-all treatments.

The breeding pipeline that follows mutagenesis unfolds over multiple generations. The first mutant generation, M1, is used mainly for seed multiplication because many induced mutations remain heterozygous. The M2 generation is where recessive mutations become phenotypically expressed, allowing breeders to screen large populations for putative mutants displaying desirable traits. Selected lines are then advanced through subsequent generations to confirm that traits are stable and heritable, and true-breeding mutants are evaluated across seasons and locations alongside existing varieties before potential release as cultivars or incorporation into breeding programs as parental material.

So what has actually been achieved in Bambara groundnut? The honest answer, the review makes clear, is promising but limited. Reported studies involving gamma irradiation, EMS and sodium azide have demonstrated induced variation in agronomic and yield-related traits, plant architecture, maturity and seed characteristics. However, most investigations have been conducted under controlled or single-location conditions with relatively small populations, and few studies have advanced promising mutant lines beyond early generations or assessed their stability across seasons. Strikingly, no mutant variety of Bambara groundnut has yet been officially released for commercial cultivation, a fact that underscores how early the field remains despite decades of mutation breeding success in other crops worldwide.

The review identifies several priority targets where mutagenesis could deliver the greatest impact. Yield improvement tops the list, with traits such as pod number per plant, seed size, biomass accumulation and harvest index all amenable to population-level screening. Earlier and more uniform maturity would reduce exposure to terminal drought in environments with short or unreliable growing seasons, while synchronized pod development would simplify harvesting. Seed nutritional quality represents a less developed but intriguing frontier, since mutations affecting metabolic pathways governing protein synthesis, carbohydrate metabolism and micronutrient accumulation could alter the crop’s already impressive nutritional profile, and biochemical screening may reveal variation invisible to conventional phenotyping.

Climate resilience is perhaps the most compelling motivation. Drought, heat, soil salinity and erratic rainfall already constrain production across many growing regions, and as climate variability intensifies, the need for adapted germplasm grows more urgent. Mutagenesis can in principle generate variation in root development, water-use efficiency and photosynthetic capacity, but the review is candid that direct evidence for mutation-derived stress tolerance in Bambara groundnut remains scarce. The authors argue that future efforts must screen mutant populations under well-defined and representative stress conditions rather than assuming that variation observed under benign conditions translates into genuine tolerance in the field.

The most forward-looking section of the review concerns integration with modern breeding technologies. Genomic resources, molecular markers and genome sequencing could link induced variation to specific phenotypes and track desirable mutations across generations. TILLING, or Targeting Induced Local Lesions In Genomes, combines conventional mutagenesis with high-throughput molecular screening to detect point mutations in genes of interest without introducing foreign DNA, making it especially valuable for crops with limited transformation capacity. Beyond genomics, transcriptomic, proteomic and metabolomic profiling could reveal the molecular and biochemical signatures underlying useful mutant phenotypes, while high-throughput phenotyping platforms using imaging and spectral sensors could enable rapid, objective, non-destructive evaluation of the large populations that mutation breeding demands.

The authors also point toward precision approaches, including CRISPR-Cas genome editing, base editing and prime editing, which allow targeted modification of specific genomic regions without the extensive off-target screening that random mutagenesis requires. These technologies have not yet been applied widely in Bambara groundnut, and their practical value will depend on improved transformation and regeneration systems, better reference genomes and functional validation of candidate genes controlling traits such as flowering time, pod development and seed composition. Combined with speed breeding, genomic selection and artificial intelligence-assisted data analysis, such tools could form an integrated precision-breeding framework that shortens breeding cycles and increases genetic gain. The review concludes that realizing this potential will require coordinated investment in large, well-characterized mutant populations, standardized genotype-specific mutagenesis protocols, multi-environment validation of promising lines, and collaborative platforms linking national and international research institutions. If those investments materialize, an ancient African legume could finally receive the breeding attention its nutritional and agronomic merits have long deserved, strengthening food and nutritional security in some of the world’s most climate-vulnerable farming regions.

Subject of Research: Mutation breeding for genetic improvement of Bambara groundnut

Article Title: Crop improvement of Bambara groundnut through mutation breeding

Article References: Mutanda, M., Musabayana, Z., & Mafirakurewa, T. (2026). Crop improvement of Bambara groundnut through mutation breeding. Discover Plants, 3(1), Article 449. https://doi.org/10.1007/s44372-026-00929-x

Image Credits: AI Generated

DOI: 10.1007/s44372-026-00929-x

Keywords: Bambara groundnut, mutation breeding, induced mutagenesis, plant breeding, food security, genetic diversity, gamma irradiation, TILLING, stress tolerance, genomics, high-throughput phenotyping, sub-Saharan Africa

The research, led by Purnama Isti Khaerani of the Research Center for Genetic Engineering at Indonesia’s National Research and Innovation Agency (BRIN) together with colleagues at Hasanuddin University and partner institutions, tackles a persistent bottleneck in mutation breeding. Irradiating seeds with cobalt-60 gamma rays at doses ranging from 50 to 1000 gray generates thousands of candidate plants, but only a fraction carry useful traits. The team first established the median lethal dose, the radiation level that kills half the seedlings, at 820 gray based on survival 21 days after planting. From the first generation of irradiated plants, they advanced material derived from 0, 250, 500, and 750 gray into the second generation, the M2, where recessive mutations typically begin to reveal themselves.

Screening for drought tolerance in soil is notoriously messy. Water moves unevenly through soil profiles, evaporation varies from pot to pot, and root architecture interacts with substrate in ways that swamp the signal breeders are trying to detect. The Indonesian team sidestepped this problem by growing the M2 seedlings in a deep-water culture hydroponic system and adding polyethylene glycol 6000 to the nutrient solution at concentrations of 10 and 20 percent. PEG is a large, inert polymer that plants cannot absorb; instead, it lowers the water potential of the solution, forcing roots to work harder to take up water. In effect, it reproduces the osmotic component of soil drought with a precision that field trials cannot match, and it does so reproducibly across hundreds of seedlings at once.

The experimental design was a split-plot arrangement, with PEG concentration as the main plot and irradiation dose as the subplot, allowing the researchers to disentangle the effects of stress severity from those of the mutagenic treatment. Seedlings were exposed to the osmotic stress for 42 days after planting in the hydroponic system, and then transferred to a greenhouse for post-hydroponic evaluations at 60 and 90 days after planting. This two-phase approach matters because a plant that survives an artificial osmotic challenge in a tank is not necessarily one that will thrive in a paddock; the later greenhouse measurements served as an early check on whether hydroponic performance carries over into more realistic growing conditions.

The results showed a clear interaction between stress level and radiation dose across several morpho-physiological traits. Under moderate stress of 10 percent PEG, mutants derived from 250 and 500 gray maintained several growth-related traits better than the wild type and showed adaptive physiological responses. At 20 percent PEG, the picture darkened for all entries: growth and physiological performance declined more sharply, reflecting the severity of the osmotic challenge. The researchers quantified that severity using a stress intensity metric, which rose from 0.68 under 10 percent PEG to 0.85 under 20 percent PEG, confirming that the higher concentration imposed a substantially harsher selection environment.

To rank the mutants objectively, the team applied two classic selection indices. The stress tolerance index, or STI, rewards genotypes that yield well both under stress and without it, while the stress susceptibility index, or SSI, penalizes those that lose the most performance when water becomes scarce. Under 10 percent PEG, the STI of the 750 gray group climbed to 0.41 from 0.23 in the wild type, while its SSI fell from 1.10 in the wild type to 0.90. The same directional pattern appeared under 20 percent PEG, though with lower STI values overall. Crucially, both the 500 and 750 gray groups posted SSI values below 1 under both stress levels, a statistical signature of lower relative susceptibility than the unirradiated controls and the 250 gray group. In plain terms, the heavier radiation doses appear to have generated a pool of mutants in which drought-resilient individuals are more common.

Individual dry-weight measurements revealed considerable variation among M2 mutants from the 250, 500, and 750 gray lineages, and a principal component analysis built on the full suite of morpho-physiological traits captured 89.5 percent of the total variation in a single two-dimensional view. That analysis cleanly separated entries that maintained their performance under stress from those that collapsed, and it flagged a short list of promising candidates under 10 percent PEG, including mutants labeled 250Gy_2P1, 250Gy_3P1, 250Gy_4P1, and the series 500Gy_1P1 through 500Gy_4P1. These are putative mutants, a deliberately cautious term: they show the phenotype the breeders want, but confirming that the trait is genetically fixed rather than a fluke of the growing environment requires progeny testing and, eventually, molecular validation.

The heritability estimates in the study add an important note of realism. Broad-sense heritability, the proportion of observed variation attributable to genetic differences, ranged from 0.24 to 0.60 during the hydroponic phase and from 0.11 to 0.80 during the post-hydroponic greenhouse evaluations at 60 and 90 days. The lower end of those ranges, particularly the 0.11 figure, signals that some measured traits are heavily influenced by environment and would make unreliable selection targets on their own. This is precisely why the authors frame their hydroponic PEG platform as a preliminary screening framework rather than a definitive test: it is designed to narrow thousands of candidates down to a manageable number that can then be subjected to multi-generation and multi-location trials.

The broader significance of the work lies in the pairing of two technologies that are individually old but jointly underused. Mutation breeding with gamma rays has produced improved crop varieties for decades, from rice to barley, because it generates novel allelic variation without the regulatory complexity of transgenic methods. Hydroponic PEG screening, meanwhile, gives breeders a fast, cheap, and controllable way to impose drought stress at scale. Combining them, and wrapping the whole effort in quantitative indices and multivariate statistics, turns what could be a fishing expedition into a structured pipeline. For a forage crop like L. tarramba, which supports livestock systems across dry tropical regions where improved varieties are scarce, even modest gains in drought tolerance could translate into more reliable fodder supplies.

There remain clear caveats. PEG-induced osmotic stress captures only part of what drought means in the field; it does not reproduce the soil physical constraints, the progressive drying cycles, or the atmospheric vapor pressure deficits that real droughts impose. The authors themselves emphasize that the promising M2 lines identified here, including the 250 and 500 gray derivatives that held their growth under moderate stress, must now move into progeny testing and molecular characterization to confirm that the tolerance traits are heritable and to locate the underlying mutations. But as a first filter, the study demonstrates that a tank of PEG-laced nutrient solution, a cobalt-60 source, and a well-chosen set of indices can rapidly surface candidate plants worth a breeder’s attention. In a warming world where forage crops face increasingly erratic rainfall, that kind of accelerated triage may become one of the most valuable tools in the plant breeder’s kit.

Subject of Research: Screening gamma-induced Leucaena tarramba mutants for drought tolerance using PEG-simulated osmotic stress in hydroponics

Article Title: Screening gamma-induced Leucaena tarramba mutants for drought tolerance under PEG-simulated osmotic stress in hydroponics

Article References: Khaerani, P. I., Hastilestari, B. R., Musa, Y., Utamy, R. F., Cai, G., Álvarez-Holguín, A., Indriatama, W. M., Husni, A., Wakano, F., Ashar, J. R., & Anshori, M. F. (2026). Screening gamma-induced Leucaena tarramba mutants for drought tolerance under PEG-simulated osmotic stress in hydroponics. BMC Plant Biology. https://doi.org/10.1186/s12870-026-10008-8

Image Credits: AI Generated

DOI: 10.1186/s12870-026-10008-8

Keywords: Leucaena tarramba, drought tolerance, gamma irradiation, mutation breeding, polyethylene glycol, hydroponics, osmotic stress, M2 mutants, stress tolerance index, heritability, principal component analysis, forage legume

Mulberry occupies a uniquely pivotal position in sericulture, the agricultural practice of raising silkworms for silk production. Unlike livestock that can be fed a varied diet, the silkworm Bombyx mori is a monophagous feeder, meaning it eats mulberry leaves and essentially nothing else. That biological constraint makes leaf quality the single most important input variable a sericulture farmer controls. The nutritional composition of mulberry foliage directly governs silkworm growth rates, larval health, cocoon yield, and ultimately the fineness and strength of the silk filament that gets reeled from each cocoon. A better leaf, in other words, translates almost linearly into better silk and better livelihoods for the millions of people, particularly in India and China, who depend on the silk trade.

The problem facing breeders is that mulberry is notoriously difficult to improve through conventional means. Most cultivated mulberry is propagated vegetatively from cuttings rather than grown from seed, which preserves desirable traits but also freezes the genetic diversity of the crop. Many of the traits that matter most to sericulture, such as leaf protein content, sugar levels, and moisture retention, are polygenic, controlled by many genes acting together rather than by a single mutation. Traditional crossbreeding can shuffle these genes, but the process is slow and constrained by the limited variation available in existing germplasm. This is where mutation breeding enters the picture. By exposing plant material to physical mutagens such as gamma rays, breeders can induce novel genetic permutations and combinations that would rarely, if ever, arise spontaneously, effectively manufacturing the raw genetic variation that selection programs need.

In the new study, researchers H. L. Ramesh, Munirajappa, and V. N. Yoganandamurthy subjected juvenile twigs of the S54 mulberry variety to a gradient of gamma irradiation doses spanning 1 to 10 kR, delivered in a cobalt-60 gamma chamber at the Indian Institute of Horticulture Research in Bengaluru. The irradiated cuttings were then cultivated in a randomized block design, a standard experimental layout that controls for environmental variation across the field, to raise the first mutant generation. From those plants, the team established putative mutant lines, so named because they carry induced changes whose genetic basis has not yet been fully characterized, and advanced them to the M2 generation, the second filial generation after mutagenesis in which recessive mutations typically begin to reveal themselves phenotypically.

The biochemical analysis of the resulting leaves revealed a striking dose-dependent pattern. While lower and higher doses produced variable effects, the 7 kR treatment stood out as a consistent winner. Leaves from cuttings treated at this dose showed significant improvements across a battery of biochemical parameters, including total protein content, soluble sugars, phenolic compounds, total chlorophyll, and moisture content. Critically, these improvements held across all three leaf maturity classes examined, from tender young leaves to coarse mature foliage. That consistency matters because silkworms are typically fed leaves of varying maturity during different larval stages, and a mutation that improves only one leaf class would offer limited practical benefit. The methods used to quantify these constituents draw on classic plant biochemistry protocols, including protein estimation with Folin’s phenol reagent, carbohydrate measurement with anthrone reagent, and chlorophyll extraction without maceration, techniques that have anchored plant physiology research for decades.

Phenolic compounds deserve particular attention in this context. These plant secondary metabolites serve multiple roles, acting as antioxidants within the plant and as bioactive compounds that can influence the physiology of organisms that consume the foliage. Previous research on mulberry has documented that the leaves are rich in polyphenolic compounds whose concentrations vary by variety, harvest period, and processing. The finding that gamma irradiation elevated phenolic content in the S54 mutants aligns with earlier reports from the same research group, who had previously shown in M5 generation mulberry mutants that irradiation enhanced leaf bioactive components. Elevated chlorophyll content, meanwhile, hints at improved photosynthetic capacity, which could underpin the observed increases in sugars and proteins by providing more carbon and energy for biosynthesis.

To test whether these biochemical gains actually mattered to the end consumer of the leaf, the silkworm itself, the researchers conducted a bioassay using crossbred PM x NB4D2 silkworms, a commercially relevant hybrid combination. Larvae were reared on leaves from the different irradiated treatments, and their commercial traits were measured at maturity. The results were unambiguous: silkworms fed the 7 kR mutant leaves displayed marked enhancements in cocoon weight, shell weight, pupal weight, filament length, denier, and renditta. Each of these metrics tells part of the silk quality story. Cocoon and shell weights reflect how much raw material the insect invested in its silk. Filament length determines how much continuous silk thread can be reeled from a single cocoon. Denier measures filament thickness, and renditta expresses how many kilograms of cocoons are required to produce one kilogram of raw silk, with lower values indicating greater efficiency.

The logic connecting leaf chemistry to silk output runs through silkworm nutritional physiology. Decades of research have established that silkworm growth and silk synthesis depend on the balance of proteins, amino acids, carbohydrates, and moisture in the diet. Proteins and free amino acids feed directly into silk fibroin and sericin production in the silk glands, while soluble sugars fuel the energetically expensive process of spinning. Leaf moisture influences how efficiently larvae can digest and assimilate their food. When the 7 kR mutant leaves delivered elevated levels of these constituents simultaneously, the silkworms converted the improved diet into heavier cocoons and longer, finer filaments, exactly the outcome a sericulture improvement program hopes to achieve.

The study builds on a substantial body of mutation breeding work in mulberry and other crops. Earlier investigations demonstrated that acute gamma irradiation produces variety-specific mutation rates and spectra in mulberry, and that mutagens can induce useful mutations in the S54 variety as early as the M1 generation. Comparable gamma-induced improvements have been documented in crops ranging from cowpea to banana, and radiation has even been used to degrade chitosan for application to mulberry plants as an elicitor. What distinguishes the new work is the full-chain demonstration, from irradiation through phytochemical profiling to a silkworm bioassay measuring commercial silk traits, providing end-to-end evidence that the induced mutation is agronomically meaningful rather than merely a laboratory curiosity.

For the silk industry, the implications are tantalizing. India is one of the world’s largest silk producers, and improvements in cocoon yield and silk quality ripple through an entire value chain that supports rural economies. A mulberry line that produces more nutritious leaves could raise productivity without expanding acreage, irrigation, or fertilizer inputs, an appealing proposition in an era of climate stress and land pressure. The researchers note that mulberry improvement through mutagenesis and polyploidy induction remains an active frontier, particularly as breeders seek varieties suited to changing agro-climatic conditions. The 7 kR S54 putative mutant now joins a growing roster of radiation-derived plant lines whose value lies not in dramatic visible transformations, but in the quiet arithmetic of biochemistry: a few more grams of protein per leaf, a few more meters of filament per cocoon, and a stronger, brighter thread of silk at the end of it all.

Subject of Research: Gamma irradiation-induced mutation breeding of S54 mulberry and its effects on leaf phytochemistry and silkworm silk production traits

Article Title: Genotypic variation, Phytochemical Composition and Bioassay Analysis in Gamma Irradiated S54 Mulberry (morus) Putative Mutant

Article References: Ramesh, H. L., Munirajappa, & Yoganandamurthy, V. N. (2026). Genotypic variation, Phytochemical Composition and Bioassay Analysis in Gamma Irradiated S54 Mulberry (morus) Putative Mutant. Indian Journal of Genetics and Plant Breeding, 86(1), 93-102. https://doi.org/10.1007/s44489-026-00002-7

Image Credits: AI Generated

DOI: 10.1007/s44489-026-00002-7

Keywords: mulberry, gamma irradiation, mutation breeding, sericulture, silkworm, phytochemicals, S54 mutant, cocoon yield, silk quality, plant biochemistry, M2 generation, genetic variation

Maize, or Zea mays L., is a global staple whose productivity depends on a suite of architectural characteristics of the ear, the female inflorescence that carries the kernels. Breeders track four traits with particular care: cob length, cob girth, kernel row number, and kernel number per row. Together these characters largely determine how many kernels a plant can fill, and therefore how much grain it produces. Although maize populations naturally harbor considerable morphological diversity, the researchers argue that creating fresh, heritable variation specifically for these yield component traits is essential if breeders are to assemble genuinely improved plant ideotypes rather than simply reshuffling existing genetic combinations.

The team’s tool of choice was the high energy pulse electron beam, or HEPE beam, a form of induced mutagenesis that differs fundamentally from conventional approaches. While chemical mutagens such as ethyl methane sulfonate and physical agents such as gamma rays have long histories in mutation breeding, electron beam irradiation delivers dense ionization energy in short pulses, producing DNA damage that can generate novel allelic variation at a comparatively high efficiency. Previous work by some of the same authors, and by other groups studying mungbean, cowpea, rice, and groundnut, has suggested that electron beams can be both effective and efficient at inducing useful mutations, sometimes outperforming gamma rays in the balance between mutation frequency and biological damage.

In the new study, the researchers irradiated an elite field corn inbred line and advanced the progeny to produce a mutant population of 213 lines. Each of these mutants was subjected to careful phenotypic characterization for the four key ear traits: cob length, cob girth, kernel row number, and kernel number per row. In parallel, the entire mutant set was genotyped with 50 simple sequence repeat markers, a class of molecular markers that detects variation in short tandem repeats scattered throughout the maize genome. This dual approach allowed the team to ask two complementary questions: whether the electron beam had created measurable variation in the traits that matter for yield, and whether that variation was reflected in the mutants’ DNA profiles.

The statistical answer to the first question was emphatic. Analysis of variance revealed that the electron beam-derived mutants differed significantly from one another for the yield component traits, and estimates of the genetic components of variation indicated that these differences were under genetic control rather than being artifacts of environment or measurement noise. In practical terms, this means the variation the beam created is real, heritable material that breeders can select upon. The team also reported high heritability estimates at both the phenotypic and genotypic levels, a combination that signals the traits respond reliably to selection and that the mutants carry stable genetic differences rather than transient physiological fluctuations induced by the irradiation itself.

Perhaps the most intriguing finding concerns trait associations. In unmodified maize germplasm, yield component traits often show negative correlations with one another: plants that pack more rows onto a cob may compensate with fewer kernels per row, or longer cobs may come at the expense of girth. These trade-offs constrain the breeder’s ability to improve all components simultaneously. When the researchers performed association analysis among the mutants, however, they found evidence that the electron beam had played a distinct role in breaking these negative associations. In other words, the mutagenic process appears to have loosened the genetic linkages and pleiotropic relationships that normally force breeders into compromises, opening the possibility of combining favorable values of multiple yield components within a single line.

The molecular marker analysis reinforced this picture from the other direction. Genotyping with the 50 SSR markers showed that the mutants were clearly distinct from the wild-type parent, confirming that the irradiation had left detectable signatures across the genome. More notably, the team found indications of new alleles present at low frequencies in the tested population, specifically associated with kernel and cob related traits. Novel alleles arising at low frequency are precisely the raw material of mutation breeding: rare variants that would not exist in the natural gene pool but that can be fixed through selection and deployed in hybrid development. The presence of such alleles suggests the electron beam did not merely shuffle existing variation but genuinely expanded it.

From the 213 mutants, the researchers selected the ten best performers based on their trait means, and one line emerged as particularly valuable. Designated EB24010202, this mutant combines a cob girth of 4.7 centimeters, a cob length of 17 centimeters, 18 kernel rows, and 28 kernels per row, a combination of desirable values across all four yield components that is rarely achieved simultaneously. Because the study’s association analysis indicated that the usual negative trade-offs had been weakened in the mutant population, a line like EB24010202 is not simply an outlier but potentially a donor of a favorable trait package that can be crossed into elite breeding material.

The implications extend beyond a single experiment. Maize productivity in India, as the authors and cited reports note, lags behind the global average, and closing that gap will require both improved management and improved genetics. Induced mutagenesis offers a way to widen the genetic base of elite inbred lines without the linkage drag that accompanies wide crosses, and electron beam irradiation appears to be an especially promising variant of the technique given its reported efficiency relative to gamma rays and chemical mutagens in several crop species. The mutants generated in this study, the authors conclude, will be of considerable importance in future field corn improvement programs, serving as donors for yield component traits and as material for mapping the genes underlying the new variation.

The work also illustrates a broader trend in modern mutation breeding: the pairing of classical biometrical genetics with molecular marker technology. By combining analysis of variance, genetic component estimation, correlation and association analysis, and SSR-based diversity profiling, the researchers were able to verify at both the phenotype and the genotype levels that their mutagenic treatment had succeeded. As sequencing and marker technologies become cheaper, this kind of two-pronged validation is likely to become the standard for mutation breeding programs worldwide, ensuring that the variation breeders chase in the field is genuinely written into the genome. For now, the message from New Delhi and Mumbai is clear: a pulsed beam of high energy electrons can crack open the genetic constraints on maize yield architecture, and the mutants it leaves behind may help feed a growing population.

Subject of Research: Electron beam-induced mutagenesis for yield component trait variation in field corn

Article Title: Assessment of Phenotypic Variability and Molecular Diversity Induced by High Energy Pulse Electron Beam for Yield Component Traits in Field Corn (Zea mays L.)

Article References: Hadiya, M. S., Mukri, G., Mondal, S., Bhat, J. S., Baliyan, S., Mallikarjuna, M. G., Singh, C., & Gupta, N. C. (2026). Assessment of Phenotypic Variability and Molecular Diversity Induced by High Energy Pulse Electron Beam for Yield Component Traits in Field Corn (Zea mays L.). Indian Journal of Genetics and Plant Breeding, 86(2), 139-146. https://doi.org/10.1007/s44489-026-00020-5

Image Credits: AI Generated

DOI: 10.1007/s44489-026-00020-5

Keywords: maize, electron beam, mutagenesis, plant breeding, genetic variability, SSR markers, yield components, Zea mays, heritability, mutation breeding, field corn, molecular diversity

Chia (Salvia hispanica L.), a member of the mint family native to Mexico and Guatemala, has attracted worldwide attention for its exceptionally high content of omega-3 fatty acids, dietary fiber, protein, and antioxidants. Its seeds can form a mucilaginous gel when hydrated, making them popular in functional foods, beverages, and health supplements. Yet despite its nutritional pedigree, chia remains what breeders call an orphan crop: genomic resources were only recently developed, and in most producing regions, very few improved varieties exist. In India, the crop’s introduction has been limited by the absence of locally adapted cultivars and by the genetic uniformity of available germplasm, which leaves little raw material for selection and improvement.

The research team confronted this bottleneck with induced mutagenesis, a technique that uses physical agents such as gamma irradiation to create random changes in the plant genome. Two chia genotypes, CHIAmpion W-83 and Nira Black Chia-1, were exposed to gamma rays, and the resulting mutant populations were advanced through successive generations to allow the genome to stabilize and recessive traits to surface. From this material, six stabilized mutant lines emerged, each carrying distinct and heritable alterations that were subsequently evaluated under field conditions for qualitative traits, phenology, plant architecture, yield components, and seed yield.

The phenotypic diversity recovered from the mutagenized populations was striking. The mutants displayed altered pigmentation patterns, crinkled leaves, chlorosis, and modified panicle architecture, all visible signs that gamma irradiation had effectively rewritten portions of the chia genome. Similar macro-mutations have long served as valuable tools in crop genetics, and in chia they provide the first tangible evidence that mutation breeding can function as a practical diversification strategy for the species. Because chia’s natural gene pool is so constrained, the ability to manufacture new variation in a single generation represents a significant technical advance for breeders working with limited germplasm.

Quantitative traits showed equally meaningful variation. Flowering time, maturity duration, plant height, branching pattern, panicle length, test weight, and seed yield all differed significantly among the mutant lines, giving breeders a palette of characters from which to assemble improved varieties. The most successful line, designated Mutant 94-1, combined early flowering and early maturity with superior branching, longer panicles, and the highest seed yield recorded among the mutants, outperforming its own parental line. In rainfed agriculture, where the growing season is dictated by erratic monsoon rainfall rather than irrigation, early maturity is a particularly prized trait: it allows a crop to complete its life cycle before terminal drought sets in, effectively escaping the worst of water stress.

A second line, Mutant 74-1-5, also demonstrated improved yield potential alongside a desirable plant architecture, reinforcing the conclusion that beneficial agronomic mutations can be recovered at useful frequencies in chia. The remaining four mutants, while not top performers for yield, were highlighted as trait-specific genetic resources that will support downstream research. Mutants 94-1 and 125-1 offer material for studying pigmentation, Mutant 148-1-2 provides a platform for investigating leaf morphology, Mutant 31-1-1 sheds light on chlorophyll expression, and Mutant 80-1 carries distinctive inflorescence shape characteristics. Each of these lines could serve as a genetic reference point for mapping the genes underlying the corresponding traits, especially now that reference genome assemblies and gene expression atlases for chia have become available to the research community.

The strategic significance of the work extends beyond the laboratory. India’s rainfed regions, which account for a large share of the country’s cultivated area, are increasingly vulnerable to climate variability, and agricultural planners are actively searching for hardy, high-value crops that can diversify dryland farming systems. Chia fits this profile in several respects. Previous research, including satellite-based observations, has suggested that chia can use less water than many other crops in warm climates, and field trials at ICAR institutes have examined its performance under deficit irrigation in semi-arid conditions. Technical bulletins describing cultivation practices for chia have also been released, indicating that the institutional groundwork for scaling the crop is already in place. What has been missing is genetic material tailored to Indian conditions, and the new mutant lines directly address that gap.

The study also reinforces the broader relevance of induced mutagenesis in modern plant breeding. For crops with narrow genetic bases, limited crossable relatives, or long generation times, mutation breeding offers a shortcut to diversity that does not involve transgenic methods and can therefore move more easily through regulatory channels in many countries. Historically, induced mutations have contributed thousands of officially released varieties worldwide, spanning cereals, legumes, and oilseeds. Applying the same toolkit to chia, a crop newly introduced to Indian agriculture, is a textbook example of how the method can accelerate domestication and adaptation of emerging species. The authors note that the identified mutants constitute elite breeding materials for developing improved chia varieties suited to Indian agro-ecological conditions and for accelerating future genetic studies in the crop.

From a technical standpoint, the pipeline used by the researchers is instructive. Mutagenesis was followed by careful generational advancement, which is essential because mutations induced in the first generation are frequently heterozygous or chimeric. Only after several generations of selfing do mutant phenotypes become fixed and reliably observable. The subsequent field characterization of the six stabilized lines, covering both qualitative descriptors and quantitative agronomic traits, mirrors the evaluation protocols used in variety development, meaning that the mutant lines are not merely curiosities but candidates for direct integration into breeding programs. Lines such as Mutant 94-1 could be tested in multi-location trials, crossed with other genotypes to pyramid favorable traits, or used as parents in varietal development aimed specifically at rainfed and semi-arid environments.

For consumers and farmers alike, the implications are compelling. A domestically adapted chia variety could open a new nutraceutical value chain for Indian dryland farmers, offering a high-margin crop alternative in regions where traditional options are increasingly unreliable. Meanwhile, the diverse mutant collection gives Indian plant scientists a homegrown resource for exploring the genetics of omega-3 accumulation, mucilage production, drought response, and flowering time in a species whose molecular biology is only now being decoded. What began as a flash of gamma radiation in a treated seed lot may ultimately help transform an ancient Aztec staple into a modern pillar of climate-resilient Indian agriculture.

Subject of Research: Gamma irradiation-induced genetic improvement of chia (Salvia hispanica L.) for rainfed agriculture in India

Article Title: Characterization of Novel Mutants of Chia (Salvia hispanica L.): A Prospective and Potential Crop for Indian Rainfed Agro-Ecologies

Article References: Santosh, H. B., Boraiah, K. M., Sarkar, B., Alam, B. K., Lakshmi, N. J., Salini, K., Harisha, C. B., Basavaraj, P. S., Halli, H. M., Kate, P., & Reddy, K. S. (2026). Characterization of Novel Mutants of Chia (Salvia hispanica L.): A Prospective and Potential Crop for Indian Rainfed Agro-Ecologies. Indian Journal of Genetics and Plant Breeding. https://doi.org/10.1007/s44489-026-00043-y

Image Credits: AI Generated

DOI: 10.1007/s44489-026-00043-y

Keywords: chia, Salvia hispanica, mutation breeding, gamma irradiation, rainfed agriculture, genetic variability, seed yield, nutraceutical crop, plant breeding, semi-arid regions, omega-3 fatty acids, mutants