Evaluation of Genetic Variability and Character association in Backcross-Derived Lines of Rice (Oryza sativa L.)

Aims: Submergence a major abiotic factor especially in paddy growing lowland areas, as these regions are prone to flood and submerged conditions. Considering, this as a major factor, the variety Sahyadri Kempumukthi, a National check for red rice, is the popular variety in hilly and transitional zones of Karnataka replacing Jyothi, cultivated on 1.20 L ha of land. It is susceptible to submergence stress. With this background, to make it tolerant, backcross breeding programme was carried out to transfer SUB 1 gene from Swarna Sub 1. Study Design: Randomized Complete Block Design. Place and Duration of Study: Department of Genetics of Plant Breeding, ZAHRS Shivamogga, Karnataka, India, Kharif 2024, July 2024 and July 2025. Methodology: The study was carried out to screen, 40 backcross derived lines (BC1F3) of cross Sahyadri Kempumukthi × Swarna Sub-1, along with four checks for fourteen yield attributing traits under the design RCBD. Top performing 20 lines based on yield performance were evaluated for 14 traits. Results: The analysis of variance showed significant variation among 14 rice attributes, as seen by the standardised range and coefficient of variation. Correlation study revealed the highest significant positive association of the test weight, spikelet fertility, number of productive tillers with grain yield indicating the effectiveness of indirect selection for these traits in improvement of grain yield per plant. Twenty promising lines were found to be better performing than parents with range of 60 to 87 q/ha.The Backcross lines K×S-6-2-1 and K×S-11-4-2, showed superior grain yield of 85.38 and 86.45 q/ha, respectively. While K×S -6-2-1 and K×S-12-4-1 were better performing for yield. Conclusion: Therefore, making these lines precious for selection. These lines are needed to be forwarded to further generations and evaluated under diverse environments to conduct MLTs, and may be proposed for further varietal release programmes.Practical implications by providing good nutritional benefits, along with good yield to farmers in turn adding to their income.