Assessment of adaptability in early rice varieties

Twelve early maturing rice varieties were evaluated for their yield performance over 30 environments created through combination of different cultural practices both in wet (kharif) and dry (rabi) seasons. Highly significant genotype-environment interaction indicated differential response of the genotypes to environmental changes. The stability analysis showed significance of linear component of variation for grain yield. Annapuma followed by Sarathi combine high yield with high stability. Parijat and Keshari with medium yield exhibited high stability. IR 36 with high yield was moderately stable. By stratifying the test environments into low, medium and high yielding ones, the results obtained by separate regression analysis brought out Annapuma, Parijat and Keshari adaptible to all environments while Sarathi and IR 36 to high yielding environments, and three tall varieties to low yielding environments. Parijat followed by Keshari were identified as unique genotypes showing relatively low response in unfavourable environments and high response to favourable ones. The usefulness of stability analysis indifferent categories of environments for assessment of adaptability of early rice varieties underrainfed uplands and its breeding implications for yield improvement are discussed.