Identification of Drought Tolerant Restorer Lines and Association Between Pollen Fertility and Spikelet Fertility in CMS Based Rice (Oryza sativa L.) Hybrids

Hybrid rice systems are based on three line Cytoplasmic Male Sterility (CMS) which has been an efficient tool in commercialization of hybrid rice technology. Therefore, identification of potential restorers in rice is the basic step in development of rice hybrids. In present study, 70 drought tolerant lines were crossed to two cytoplasmic male sterility lines viz., IR58025A and IR79156A and F sub(1)s were analyzed for pollen fertility (1% I-KI solution) and spikelet fertility. Based on the fertility restoration in F1' s, 25 genotypes were restorers. Highly significant correlations of 0.93 and 0.88 between pollen fertility and spikelet fertility were obtained in hybrids involving CMS line IR 58025A and CMS IR 79156A, respectively. KMR 3, IR 84891-B-112-CRA-15-1 and IR79906-B-192-2-2 produced F sub(1)s with highest pollen fertility and spikelet fertility and are considered as promising restorers.