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Background: Rice is the staple food for billions of people globally and contains numerous essential nutrients. Among the nutrients, zinc and iron are vital for several growth metabolisms in plants and humans. Therefore, deficiency of these nutrients causes hidden hunger. However, understandingthe genetic variability of rice germplasm is required for improvement of grain yield, yield contributing and nutritional traits. The present study aimed to examine the variability, heritability, character association and path analysis in zinc and iron-rich rice landraces. Methods: The present investigation was carried out with 37 genotypes of rice in a randomized block design with two replications during Kharif-2021 at Regional Agricultural Research Station (RARS), Maruteru. Result: The studies on variability, heritability and genetic advance as percent mean results revealed moderate GCV and PCV coupled with high heritability and genetic advance as percent mean recorded for days to 50 per cent flowering, plant height, zinc content, iron content and grain yield plant-1 indicating scope for simultaneous improvement of these traits along with grain yield plant-1. Character associations and path analysis revealed positive and significant association coupled with a high positive direct effect for grains panicle-1, zinc content and productive tillers plant-1, indicating the effectiveness of direct phenotypic selection for these traits in the improvement of grain yield plant-1. [ABSTRACT FROM AUTHOR]

Principal Component Analysis (PCA) was carried out to find the genetic divergence among 35 zinc-rich landraces of rice along with two checks for yield and quality traits. Three principal components with Eigen value more than one explained maximum variation with a total contribution of 78.33 per cent of the total variability. Principal Component 1 (PC 1) contributed a maximum of 51.71 per cent, while PC 2 contributed to 18.71 per cent and PC 3 contributed to 7.96 per cent towards the total variability. Yield and quality traits such as days to 50 per cent flowering, number of productive tillers plant-1, grain yield plant-1, head rice recovery per cent, iron content and volume expansion ratio explained the maximum variance in PC 1. The results of the 2D scatter diagram revealed GM-120 and GM-173 landraces to be the most diverse. These genotypes were identified to be high yielding and nutritionally rich, compared to BPT 5204. Hybridization of these genotypes is expected to result in desirable transgressive segregants for yield, quality and nutritional traits. [ABSTRACT FROM AUTHOR]

Rice is generally shows variable level of sensitivity to salinity during its developmental stages and remarkably sensitive during young seedling stage and early reproductive phase. Quantifying the level of salt tolerance based on salt stress indices is an effective method in identification of tolerant genotypes. In this study, the salt stress indices were used to identify best performing genotypes based on salt susceptibility indices (SSI) and salt response indices (SRI) as relevant parameters. Among the 39 genotypes studied, 29 showed better endurance to salt susceptibility indices, among them Pokkali, IR72132-AC-6-1 and IR70869-B-P-13-2 performed well with least SSI, which refers more tolerance with lesser yield reduction, whereas IR29 was vice-versa to the above. Genotypes IR72593-B-19-2-3-1, IR73104-B-1-1-3-2-1 and IR74802-3R-7-1-2 had a better performance with early flowering and highly responsive to salt stress with lower percent yield reduction. The phenotypic variation is higher than genotypic variation for all traits except for flowering duration and it indicates presence of variability for different traits. High heritability with variability, genetic advance and better salt stress indices indicates involvement of additive gene action and can be manipulated and utilized in further breeding program. [ABSTRACT FROM AUTHOR]