Genetic variability, character association and grain quality assessment in segregating rice (Oryza sativa L.) lines of TUNGA × KPR1

Micronutrient enrichment and desirable grain quality are crucial targets in rice improvement to address malnutrition and enhance consumer acceptance. The present study was conducted to evaluate the performance of segregating lines of cross, Tunga x KPR 1 in an augmented design during Kharif 2022 - 23 at the Zonal Agricultural and Horticultural Research Station (ZAHRS), Mudigere to investigate genetic variability parameters, correlation, direct and indirect effects and grain quality parameters. The analysis of variance (ANOVA) revealed significant phenotypic and genotypic differences for all the studied characters. High values of phenotypic coefficient of variation (PCV) and genotypic coefficient of variation (GCV) were for the number of filled grains per panicle (NFG; 20.39 and 20.03 % respectively). Moderate PCV and GCV values were recorded for grain yield per plant (GY; 16.39 %, 11.29 %) and spikelets per panicle (SP; 15.28 %, 14.84 %). Most of the characters recorded minimal differences between PCV and GCV. The NFG showed high heritability values (96.59 %) and high values of genetic advance as a percentage of mean (GAM; 40.62 %). Filled grains per panicle, productive tillers per plant, spikelets per panicle, tillers per plant and panicle length (PL) showed a positive and significant association with grain yield. A positive direct effect on grain yield was observed for days to maturity (DM), productive tillers per plant, panicle length and filled grains per panicle. The top 10 superior lines from the cross were analyzed for quality parameters such as zinc (35.65 ppm), iron (13.92 ppm) and amylose content (28.20). All three traits, zinc (0.37), iron (0.31) and amylose (0.35) have a weak positive correlation and they were found to be promising and can be used in crop improvement programmes. Entry 44,41 and 12 have outperformed all other lines in zinc and iron content respectively.