The research, conducted at the experimental farm of ICAR-Vivekananda Parvatiya Krishi Anusandhan Sansthan in Hawalbagh, Uttarakhand, at an altitude of roughly 1,250 metres above sea level, drew its plant material from a mixture of institutional gene banks and field explorations. Fifteen accessions came from the National Bureau of Plant Genetic Resources in New Delhi, forty from its regional station in Bhowali, one from the regional centre of the Central Institute of Temperate Horticulture in Mukteshwar, and fifteen were collected directly from farmers’ fields in the Kumaon and Garhwal regions. In other words, about 82 percent of the material originated from government research institutes while 18 percent came from targeted collection missions, giving the team a blend of formally conserved and locally evolved germplasm.

The accessions were grown during two consecutive cropping seasons, 2021–22 and 2022–23, in a randomised complete block design with two replications. Each accession occupied three-row plots of 2.40 by 1.35 metres, with rows spaced 45 centimetres apart and plants 30 centimetres apart within rows. From each 24-plant plot, ten randomly chosen individuals were scored for a battery of qualitative descriptors following the International Board for Plant Genetic Resources guidelines for Brassica and Raphanus, while 27 quantitative traits were measured from germination through to harvest. These included days to germination, plant height, petiole dimensions, days to bolting and flowering, root length and width, leaf number, total soluble solids, whole-plant weight, leaf and root yields per plant, biomass partitioning, pod length, seed yield, vitamin C, total polyphenols, four separate antioxidant assays, total chlorophyll and total carotenoids.

The pooled analysis of variance across both years revealed highly significant differences among genotypes for nearly every trait examined, from root length and width to days to bolting, total soluble solids and the full suite of antioxidant measures. The magnitude of the mean squares told its own story: seed yield per plant topped the list at 872.55, followed by root width at 466.85, total antioxidant activity at 426.81, ferric reducing antioxidant power at 314.57 and DPPH radical scavenging activity at 285.49. Descriptive statistics filled in the picture. Days to germination ranged from 5.13 to 9.87 days, plant height from 25.14 to 43.10 centimetres, and plant spread from 38.50 to 69.37 centimetres, indicating the presence of both compact and spreading growth habits. Root length spanned 10.95 to 24.90 centimetres and root width 2.38 to 7.00 centimetres, while leaf number per plant varied more than fourfold, from 9.40 to 37.30.

Perhaps the most agronomically striking variation involved bolting, the premature transition from vegetative growth to flowering that ruins root quality. Days to bolting ranged from 55.83 to 99.17 days, with a mean of 75.94, and flowering extended as late as 110.75 days after sowing. Late bolting is a prized trait in mountain radish production because it extends the harvest window, and the Dev Prayag collection emerged as a standout for this characteristic. Total soluble solids averaged 7.65 degrees Brix but ranged from 6.01 to 10.19, while biochemical assays showed total polyphenols between 0.48 and 1.46 milligrams of gallic acid equivalents per gram of dry weight, ABTS inhibition between 48.61 and 69.01 percent, total antioxidant activity between 20.53 and 69.69 millimolar Trolox equivalents per gram, and FRAP values between 22.72 and 76.23 millimolar ferrous sulphate equivalents per gram. Total chlorophyll ranged from 0.71 to 2.95 milligrams per gram, hinting at differences in photosynthetic potential among the accessions.

Genetic parameter estimates strengthened the case that much of this variation is exploitable. Across the pooled analysis, the genotypic coefficient of variation ranged from 0.95 percent for ABTS to 75.05 percent for seed yield per plant, and for most traits the phenotypic coefficient of variation only slightly exceeded its genotypic counterpart, pointing to strong genetic control with limited environmental noise. Heritability in the broad sense reached 99.67 percent for seed yield per plant, and genetic advance as a percentage of the mean climbed to 154.34 percent for the same trait. Seed yield, root yield, whole-plant weight, leaf yield, leaf and root weight percentages, total chlorophyll and total carotenoids all combined high variability with high heritability and high genetic advance, a statistical signature that typically indicates additive gene action and a strong response to direct selection. Traits with low or inconsistent genetic advance, by contrast, are likely shaped more by genotype-by-environment interaction and would need multi-location testing before breeders commit to them.

To untangle how these traits cluster together, the team turned to multivariate statistics. Principal component analysis showed that the first two components together explained 29.20 percent of total variation, with PC1 accounting for 16.47 percent and PC2 for 12.76 percent. PC1 loaded positively on morphological and developmental traits such as seed yield, plant height, plant spread and petiole length, but negatively on antioxidant measures including DPPH, total antioxidant activity and FRAP. PC2 was dominated by root yield per plant, root weight percentage and whole-plant weight, while vegetative traits such as leaf weight percentage and petiole width loaded negatively. The relatively modest share of variance captured by the first two components indicates that diversity in this germplasm is distributed across many dimensions rather than concentrated in a single axis, a pattern consistent with a complex, multidimensional genetic base. Squared cosine values highlighted leaf weight percentage, DPPH, FRAP and total antioxidant activity as the traits best represented in the PCA space, while accessions IC 391218, IC 341190, IC 356498, IC 391330 and IC 391583 contributed most strongly to genotype differentiation.

Hierarchical clustering using Ward’s method then sorted the 67 accessions into four groups of 40, 17, 2 and 8 genotypes respectively. The team was candid about the limits of this grouping: average silhouette widths were low, at 0.078 for the four-cluster solution, meaning the clusters should be treated as exploratory rather than definitive. Even so, the smallest cluster was the most interesting. Cluster III contained just two accessions, Dunagiri NSP and Dunagiri Mandir, which stood apart from the rest and combined superior root yield with longer, wider and heavier roots, marking them as prime donor parents for yield improvement. Cluster IV, composed of eight genotypes mostly collected from the Chamoli district of Uttarakhand, including Badrinath, Gwaldam, Joshimath and Dev Prayag, was characterised by vigorous vegetative growth, hinting that geographic origin has shaped genetic similarity. The Mukteshwar collection, meanwhile, distinguished itself through superior antioxidant activity, and IC 255478 through high leaf yield.

Correlation analysis added a layer of nuance that breeders will need to navigate carefully. Root yield per plant was positively associated with whole-plant weight, petiole length, petiole thickness and root weight percentage, offering reliable indirect selection indicators for yield. However, root yield showed a negative association with the antioxidant traits DPPH, total antioxidant activity and FRAP, suggesting an inverse relationship between bulk production and antioxidant potency within this germplasm. Interestingly, the antioxidant measures themselves were strongly intercorrelated, implying shared biochemical pathways, while biochemical traits such as vitamin C, chlorophyll and carotenoids showed no meaningful relationship with phenological traits like days to germination or flowering. That independence is good news: it suggests nutritional quality can be improved without disturbing maturity timing. Similar yield-antioxidant trade-offs have been reported in Indian mustard, garlic and caigua, so the pattern appears to be a recurring challenge in horticultural crops.

The authors are careful to frame their candidates as preliminary rather than finished products. Dunagiri NSP, Dunagiri Mandir, IC 391218, IC 255478 and IC 391330 now require validation through multi-location trials, formal genotype-by-environment analysis and multi-trait selection indices before they enter cultivar development. Still, the strategic implications are clear. Crossing divergent clusters, for example pairing the high-yielding Dunagiri accessions with the vigorous Chamoli collections or the antioxidant-rich Mukteshwar material, could combine complementary traits in a single genetic background. Looking further ahead, the study argues that phenotypic selection should be paired with molecular tools and genomic selection to identify and introgress alleles governing root yield, bolting behaviour and antioxidant activity. As global demand grows for vegetables that deliver both calories and functional-food benefits, the humble Himalayan radish may prove that some of the most valuable crop genes are hiding not in high-tech laboratories, but in mountain fields tended for generations.

Subject of Research: Genetic and biochemical diversity in Indian Himalayan radish germplasm

Article Title: Genetic and biochemical traits diversity in germplasm of Indian Himalayan radish (Raphanus sativus L.)

Article References: Dev, R., Hedau, N. K., Santhiya, S., Pal, R. S., Paschapar, A., Punetha, S., & Kant, L. (2026). Genetic and biochemical traits diversity in germplasm of Indian Himalayan radish (Raphanus sativus L.). Discover Plants, 3(1), Article 432. https://doi.org/10.1007/s44372-026-00902-8

Image Credits: AI Generated

DOI: 10.1007/s44372-026-00902-8

Keywords: radish, Raphanus sativus, germplasm, genetic diversity, Indian Himalayas, plant breeding, antioxidants, heritability, principal component analysis, hierarchical clustering, root yield, landraces