AMMI and WAASB-Based Stability Model Analysis for Identifying High-Yielding Stable Blast Resistant Rice (Oryza sativa L.) Genotype

Özet

Rice (Oryza sativa L.) is the main staple food in Bangladesh. However, the recent outbreak of Pyricularia grisea-driven rice blast is a significant concern to the food security in Bangladesh, as it can cause 70-80% yield losses globally. Researchers at the Bangladesh Rice Research Institute (BRRI) introgressed blast-resistant Pi9 and Pb1 genes into the genetic background of BRRI dhan28 and developed advanced fixed lines. However, to understand the yield potential and adaptability, breeders prefer multi-environmental trials (METs). This study aims is to select a superior and stable blast-resistant rice (BRR) genotype using the WAASB and WAASBY statistical models. This study evaluated six rice genotypes across ten different environments using a randomized complete block design (RCBD) with three replications during the 2021-22 and 2022-23 Boro rice growing seasons. The analysis focused on grain yield (GY) and its contributing traits. Highly significant variation was observed among the traits for genotype by environment interaction (GEI). The AMMI model further confirmed that PC1 and PC2 captured 66.1% and 77.2% of the GEI variance for grain yield, emphasizing the importance of stability analysis. The AMMI biplot illustrated that V3 had minimal interaction and greater suitability, whereas V5 showed greater variation. The WAASB stability index revealed that V3 consistently ranked as the most stable and high-yielding genotype, followed by V6 and V2. Conversely, V1 and V5 were identified as unstable with below-average yield. Rangpur (E4) was also found to have more blast-prone areas, as indicated by disease incidence records. The WAASBY ranking further validated these findings, confirming that the BR(Path)13784-BC3-61-1-6-HR3 (V3) genotype's stability and productivity may be considered for variety release, replacing mega-popular variety BRRI dhan28 (V5). Simultaneously, Genotypes BR(Path)13784-BC3-63-6-4-HR6 (V4) and BR(Path)12452-BC6-53-21-11 (V2) should also be considered for future blast-resistant rice varietal breeding programs.