Phenotypic stability for grain yield in rice

Twenty six rice genotypes were evaluated at the Rice Research Station, Orissa University of Agriculture & Technology, Bhubaneswar, over eight environments during wet season 2000 and dry season 2001 for the assessment of yield and yield stability. Pooled analysis of variance for grain yield over environments showed highly significant differences among genotypes, environments and genotype-environment (GxE) interaction indicating diverse and variable nature of cropping environments. The genotypes were classified into four adaptive groups based on regression co-efficient (b) and deviation from regression (S2 d). Majority of the high yielding genotypes in both mid-early group (Daya, Lalat, Sebati, Konark and ORS 199-5) and medium maturity group (Bhuban, Birupa, Meher, Kharavela and Tapaswini) with high yield potential have either above average (b>1) or below average (b1) responses. The genotypes Sarathi and IR 36 with low yield potential exhibited average stability with unit regression and S2 d values not significantly different from zero.