Analysis of the Generation Mean for Yield and Its Contributing Traits in Rice (Oryza sativa L.)

Abstract

The present study evaluated genetic parameters associated with yield and its contributing traits in rice (Oryza sativa L.) through generation mean analysis. Five generations, namely P1, P2, F1, F2 and F3, developed from four crosses involving NVSR 2565, NVSR 2272, Devli Kolam and Dhanhar Black, were assessed under upland conditions during Kharif 2024. The experiment was laid out in a compact family block design with three replications. Data were recorded for thirteen traits, encompassing phenological attributes, yield and yield-related characters, and grain-quality parameters. Analysis of variance revealed significant differences among generations for all the traits across the four crosses, indicating the existence of sufficient genetic variability and justifying further genetic analysis. The C and D scaling tests confirmed the presence of epistatic interactions, suggesting that the simple additive–dominance model was inadequate for explaining the inheritance of several traits. Under the five-parameter model, mean, additive, dominance, additive × additive and dominance × dominance effects were found to be simultaneously significant for selected traits, including plant height in cross I, productive tillers per plant in crosses I and II, panicle length in cross IV, kernel breadth in cross I and 100-grain weight in cross I. Duplicate epistasis was predominant for several traits and cross combinations, while complementary epistasis was also observed in specific cases. Overall, the findings demonstrate the involvement of both fixable and non-fixable gene effects in the inheritance of yield and associated traits. Therefore, appropriate breeding strategies should be adopted according to the trait- and cross-specific genetic architecture to achieve effective improvement in upland rice.