Identification and analysis of low light tolerant rice genotypes in field conditions and their SSR-based diversity in various abiotic stress tolerant lines
The yield potentiality of kharif rice is not completely used even under well-irrigated agro-ecosystem, mainly due to lowirradiance by overcast cloud throughout the growing season in eastern India. We observed more than 50% yield reduction compared to theperformance of 100 high-yield genotypes for consecutive three years both under open and 30–35% reduced light intensity, mainly by 34%,25% and 12% reduction of panicle number, grains per panicle and test weight. As per the analysis of variance, genotypic varianceexplained 39% of the total yield-variation under shade with 58% heritability. Overall, the maintenance of equal panicle per plant in bothopen and shade has the highest association with shade tolerance. Purnendu, Sashi and Pantdhan19 showed less than 28% yield-reductionby maintenance or even by increasing grain numbers under shade and test weight. On the other hand, maintenance of an equal numberof panicle under both situations was the key to the tolerance of Bhasamanik, Sasarang, Rudra and Swarnaprabha. As compared toopen, we noticed the improvement of chlorophyll a and b under shade but saw a poor correlation with the shade tolerance index.Comparing the net photosynthesis rate (Pn) in eight genotypes, we found the best tolerant line ranked last with least Pn at low light intensity(\400 $\mu$mol m-2 s-1). We also identified diverse parental combinations between newly identified shade tolerant and abiotic stress toleranthigh-yielding rice lines following diversity analysis using 54 simple-sequence repeats. Thus, the selected tolerant lines from a large set ofgenotypes with different adjustment ability to keep up high yield under low light intensity can be used for physiological, molecular analysisas well as pyramiding of traits.
Volume 101, 2022
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