Inquest of climate-smart rice (Oryza sativa L.) genotypes considering multi-trait selection index and genotype-environment interaction at a variable duration of submergence

Submergence is a significant natural disaster that severely reduces rice yield. The research was conducted at Gazipur Agricultural University, involving 48 rice genotypes that were tested under 14 and 21 of Days of Submergence (DS) to identify rice submergence tolerance genotypes based on morpho-physiological characteristics in the F2 population. The experiment employed a split-plot design with three replications. Significant variation was observed in all traits under submergence, with 21 DS showing a greater detrimental effect than 14 DS. The phenotypic coefficient of variance exceeded the genotypic coefficient of variance for all traits, with most traits exhibiting moderate to high heritability (30–60 %). High Genetic Advance (GA) was noted in days-to-maturity (54.02), Plant Height (PH) (61.57) and Plants per Hill (PPH) (87.36). Grain yield showed significant positive correlations with straw yield (r = 0.571**, r = 0.501**, r = 0.516**), Filled Grain per Panicle (FGP) (r = 0.564**, r = 0.425**, r = 0.770**) and PPH (r = 0.729**, r = 0.511**, r = 0.509**) in control, 14 DS and 21 DS conditions. Principal components analysis revealed that five components accounted for 78.45 % of the total variability, with biplot illustrations depicting genotype-trait relationships. A hierarchical-clustering heatmap classified the genotypes into distinct clusters based on the stress tolerance index. The genotypes SR004, SR005, SR006, SR008, SR010, SR012, SR015, SR016, SR018, SR022, SR026, SR030, SR032, SR033, SR034, SR036, SR038, SR039, SR041, SR044, SR045 and SR047 exhibited tolerance under both 14 and 21 DS.