Researchers from the Indian Council of Agricultural Research-Indian Institute of Spices Research in Kozhikode, along with collaborators from agricultural universities across India, evaluated 21 turmeric genotypes representing diverse agro-ecological regions of the country under greenhouse conditions over two consecutive growing seasons from 2021 to 2023. The trial was conducted at a commercial greenhouse facility in Telangana, where a multi-span structure covered with UV-stabilized diffuse polyethylene film and insect-proof netting provided a regulated microclimate. Natural ventilation through lateral roll-up openings and retractable shade screens during peak solar hours maintained conditions that minimized the environmental variability that typically plagues open-field cultivation.

The genotypes were grown in 24-liter plastic pots filled with sterilized coir husk chips, arranged in a completely randomized design with two replicates. Each genotype was planted in 40 pots with single 30-day-old sprouted rhizomes, and standard agronomic practices along with fertigation were followed throughout the crop cycle. The researchers meticulously recorded fresh rhizome yield, dry recovery percentage, oleoresin content, essential oil content, and curcuminoid concentration—the trio of quality parameters that determine turmeric’s commercial and medicinal value.

The results revealed striking genetic diversity across all measured traits. Fresh rhizome yield ranged from 378 to 1,014 grams per clump across the pooled analysis, while dry recovery varied between 15 and 28 percent. Oleoresin content spanned from 3 to 12 percent, essential oil from 2 to 9.5 percent, and curcuminoid content from 0.7 to 4.0 percent. Two genotypes—IISR Pragati and NDH 8—emerged as consistently high-yielding and stable performers. IISR Pragati recorded the highest pooled fresh rhizome yield at 959.08 grams per clump, followed closely by NDH 8 at 938.83 grams per clump, demonstrating that these varieties could reliably deliver top productivity even under the reduced environmental fluctuations of greenhouse cultivation.

On the quality front, Waigon Turmeric stood out with consistently superior oleoresin and essential oil contents, achieving pooled means of 12.07 percent and 8.50 percent respectively. Meanwhile, IISR Pragati demonstrated the highest and most stable curcuminoid content at 3.24 percent across both seasons, a finding of particular significance for pharmaceutical applications where curcumin concentration is the primary value driver. Chhattisgarh Haldi 2 showed exceptional dry recovery at 25.32 percent, making it attractive for processing industries where the ratio of dried to fresh rhizome directly affects economic returns.

Perhaps the most revealing finding came from the statistical decomposition of variation. Using pooled analysis of variance across the two seasons, the researchers found that genotype effects accounted for the majority of total variation in all five traits—58.28 percent for fresh rhizome yield, 75.31 percent for dry recovery, 60.41 percent for oleoresin, 77.28 percent for essential oil, and a remarkable 80.97 percent for curcuminoid content. Genotype-by-season interaction contributed a further 9 to 24 percent depending on the trait, while the season effect itself was comparatively minor. This stands in sharp contrast to open-field studies, where environmental factors and their interactions with genotype typically dominate the variation in yield and quality traits.

The researchers employed GGE biplot analysis to visualize these relationships graphically, confirming that genotype and genotype-by-environment interaction contributed more to trait variation than the environment itself under greenhouse conditions. This finding carries profound implications for breeding strategy. In traditional field cultivation, breeders must select for phenotypic stability—the ability of a genotype to perform consistently across unpredictable and changing environments. Under controlled conditions, however, the breeding paradigm shifts entirely. With environmental flux, pests, and pathogens less formidable barriers, breeders can focus on maximizing genetic potential for specific traits such as rapid growth, performance under modified light spectra, and optimized plant architecture.

Correlation analysis further illuminated the complex physiological trade-offs inherent in turmeric improvement. Fresh rhizome yield exhibited a significant positive association with curcuminoid content, but was negatively correlated with dry recovery, oleoresin content, and essential oil content. This inverse relationship between yield and certain quality parameters suggests a dilution effect, where rapidly growing rhizomes with higher moisture content accumulate lower concentrations of secondary metabolites per unit mass. Such trade-offs have long frustrated breeders attempting to improve both productivity and phytochemical quality simultaneously, and they underscore the necessity of multi-trait selection approaches that can identify genotypes achieving an optimal balance rather than excelling in a single dimension at the expense of others.

To address this challenge, the researchers applied two modern multi-trait selection indices—the Multi-Trait Genotype-Ideotype Distance Index (MGIDI) and the Factor Analysis and Ideotype-Design based on Best Linear Unbiased Prediction (FAI-BLUP). Factor analysis revealed two principal dimensions underlying the trait variation, together explaining 82.82 percent of total phenotypic variation. The first factor was primarily associated with fresh rhizome yield, curcuminoid content, and dry recovery, while the second factor captured oleoresin and essential oil content. At a selection intensity of 20 percent, the MGIDI identified Roma, Waigon Turmeric, IISR Prathiba, and CO 3 as the most promising genotypes. The FAI-BLUP index, using an ideotype targeting simultaneous increases in yield and quality traits, identified Roma, IISR Prathiba, CO 3, and IISR Pragati. The two models showed 75 percent concordance, with Roma, IISR Prathiba, and CO 3 consistently selected by both approaches across seasons.

The predicted genetic gains from multi-trait selection were substantial for quality parameters. Curcuminoid content showed a predicted gain of 33.56 percent, oleoresin content 11.54 percent, and essential oil content 9.37 percent. These gains came at a modest cost—fresh rhizome yield declined by 4.72 percent and dry recovery by 3.30 percent among the selected genotypes. However, in the economics of protected cultivation, where quality consistency commands premium pricing and pharmaceutical buyers demand reliable phytochemical profiles, this trade-off represents a favorable exchange. The researchers note that the modest sacrifice in raw yield can be compensated by the marked recovery in curcuminoid content per unit area, along with greater predictability in quality traits that reduces commercial risk.

This study represents the first systematic evaluation of turmeric genotypes for yield and quality under controlled greenhouse conditions, and its findings carry implications that extend far beyond the spice itself. As controlled-environment agriculture expands globally to meet the demands of growing urban populations and increasingly quality-conscious consumers, the principles demonstrated here—that genotype selection becomes the dominant determinant of both yield and phytochemical quality when environmental noise is minimized—apply broadly to other high-value specialty crops. The research also highlights the importance of tailoring breeding objectives to production systems: varieties optimized for open-field stability may not be the same ones that excel under the regulated conditions of a modern greenhouse. For India, which produces 80 percent of the world’s turmeric and leads global exports, these findings offer a roadmap for enhancing the consistency and pharmaceutical value of one of its most iconic spice crops, potentially transforming how turmeric is grown, graded, and marketed in the decades ahead.

Subject of Research: Genetic stability of yield and phytochemical quality traits in turmeric genotypes under controlled greenhouse cultivation

Article Title: Yield and quality traits stability of turmeric (Curcuma longa L.) genotypes under greenhouse conditions

Article References: Silaru, R., Sounderarajan, A., Kotha Madduri, Y., & Duraisamy, P. (2026). Yield and quality traits stability of turmeric (Curcuma longa L.) genotypes under greenhouse conditions. Frontiers in Horticulture, 5, Article 1899925. https://doi.org/10.3389/fhort.2026.1899925

Image Credits: AI Generated

DOI: 10.3389/fhort.2026.1899925

Keywords: turmeric, Curcuma longa, greenhouse cultivation, curcuminoids, genotype-environment interaction, yield stability, oleoresin, essential oil, MGIDI, FAI-BLUP, controlled environment agriculture, plant breeding