Abstract

Variation in streptomycin sensitivity and dark sensitivity of 36 rice genotypes of 3 different maturity groups was studied. Streptomycin sensitivity and dark sensitivity of rice genotypes were expressed in terms of bleaching index (BI) and senescence index (SI) respectively. Genotypes of each maturity group showed wide variation in their BI / SI value. The objective of this investigation was to find relationship of BI / SI parameter with yield, adaptability and stability in yield performance of rice genotypes. Yield performance of rice genotypes were evaluated over 12 environments. Adaptability and stability analysis were done following linear regression model of Eberhart and Russell and AMMI Stability Value (ASV) of purchase. BI parameter showed positive correlation with yielding ability and deviation from regression and negative correlation with adaptability parameter (b) for all the 3 maturity groups. But SI parameter showed negative correlation with yielding ability and positive correlation with adaptability parameter (b) for all the 3 maturity groups. This experimental study revealed that sensitivity of rice genotypes to SM in terms of BI could be used to predict yielding ability of genotypes and dark sensitivity (SI) could be used to indicate adaptability to rich environments or poor environments. This novel approach may help the breeder in indirect selection of high yielding genotypes and genotypes well adapted to rich or poor environments at an early seedling stage before going for multilocation trials.

Key words: Streptomycin, dark treatment, Oryza sativa, adaptability.