Stability Parameters for Yield and Its Components of some Rice Varieties under Different Sowing Dates

Multi-environment trials (METs) are essential in plant breeding programs to estimate crop productivity and adaptability across various environments. The present study was carried out at Rice Research Farm, Sakha Agricultural Station – Kafrelsheikh – Egypt, during the two seasons, 2022 and 2023 under three sowing dates, April 20th, May 10th and May30th on three rice varsities i.e. Sakha 106, Sakha 107 and Sakha 109. A split – plot design in a randomized complete block design with three replications was used in both seasons. Combined analysis of variance showed highly significant mean squares for the varieties (V), environments (E) and their interaction (V x E) for grain yield/plant. The mean grain yield /plant of three varieties varied among the six environments with arrange from 35.32 g/ plant to 45.81 g/ plant under different environments. The genotypes showed a significant response to the early sowing date 20th April compared to the late sowing date 30th May in both seasons. The analysis of variance for phenotypic stability revealed that, linear and non- linear components of variation were highly significant for grain yield/plant. The environments E1, E2 and E4 were located in the right side of perpendicular line indicating that they were the favorable conditions as they gave higher grain yield / plant. While, the environments E3, E5 and E6 located far from the biplot origin implying had higher contribution to G x E interaction and resulted in unstable performance of genotype for grain yield / plant. The rice variety Sakha-109 reveled bi value lower than 1,it mean that this variety suitable for poor environments while, Sakha-106 and Sakha-107 gave values of bi more than one, this indicates that these genotypes are well-suited for cultivation under favorable conditions environments. Regarding to S2di all rice varieties showed values that did not deviate significantly from zero and are therefore considered stable for harvest index %. The W²ᵢ and CVᵢ measurements were not discussed.