GENOTYPE BY ENVIRONMENT INTERACTION AND STABILITY ANALYSIS IN RICE GENOTYPESNitiprasad Namdeorao Jambhulkar, Lotan Kumar Bose, Kanailal Pande and Onkar Nath Singh
Rice (Oryza sativa L.) is the staple food for a large proportion of the worlds population. India is one of the largest rice producing country of the world. Although more than 900 rice varieties have been released in India, many of them are no longer cultivated within a few years of release due to inconsistent performance in diverse environments; only a few varieties with stable performance continue to be under cultivation after 15 to 20 yr of their release. Hence, evaluation of genotype for its stable performance across the environment is vital. So, the objective of the study is to identify the stable genotypes across the environment. Field experiments were conducted with nine rice genotypes for four consecutive years from 2010 to 2013 in a randomized complete block design with three replications. The combined analysis of variance showed significant GEI effect. AMMI model was used which shows that 95% of the variance was explained by the first two interaction principal component analysis axis. The biplot display of PCA scores plotted against each other provides visual inspection. Hence, another new approach called AMMI Stability Index (ASI) was proposed which provides quantitative value for stability analysis which helps in the interpretation of the results. Based on ASI genotype GEN6 was found to be most stable followed by GEN4; whereas GEN3, GEN7 and GEN9 were most unstable. Based on the ASI score and grain yield, the nine genotypes were classified into three clusters. First cluster comprised of the stable genotypes GEN6 and GEN4; second cluster comprised of intermediate stable genotypes GEN8, GEN2, GEN5 and GEN1 and third cluster contains unstable genotypes GEN9, GEN7 and GEN3. Due to low ASI score and good average grain yield over tested environments GEN6 can be considered as a universal variety with good and stable performance over the years.
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