Unveiling genetic basis of yield and salinity tolerance in rice (Oryza sativa L.) through insights from generation mean analysis

Abstract

Rice (Oryza sativa L) serves as a primary food source for over a billion people worldwide and is encountering challenges in yield due to the increasing global population and climate changes. Understanding the genetic variations that underlie complex traits is crucial for its enhancement and this can be accomplished through generation mean analysis. In this study, investigation was made to study the genetic mechanisms governing important quantitative traits, specifically yield and salinity tolerance in rice. The study involved six generations (P1, P2, F1, F2, B1 and B2) resulting from two crosses between three parents. The investigation specifically focused on generation mean analysis, assessing twelve traits includes days to flowering, plant height, total number of tillers, number of productive tillers, panicle length, flag leaf length, flag leaf width, number of filled grains per panicle, total number of grains per panicle, spikelet fertility, thousand-grain weight and single plant yield in the two crosses. In Cross I (ADT 45 × APD 19002), traits such as plant height, days to fifty percent flowering, total number of tillers and total number of grains per panicle exhibited opposing signs for dominance × dominance (l) and dominance (h), indicating a prevalence of duplicate epistasis. At the same time, additive and additive × additive gene effects influenced total number of tillers, plant height, total number of grains per panicle, number of filled grains per panicle and spikelet fertility. In Cross II (CO 54 × APD 19002), total number of tillers, plant height, flag leaf length, total number of grains per panicle, spikelet fertility and single plant yield suggested a predominance of duplicate epistasis. Further, the total number of grains per panicle, total number of tillers per plant, spikelet fertility and thousand-grain weight were primarily governed by additive and additive × additive gene effects. These observations show the feasibility of enhancement through selection in subsequent generations, emphasizing the necessity of integrating selection with salinity tolerance screening for the development of high-yield, salinity-tolerant rice varieties.