Male-sterility inducing cytoplasmic effects on combining ability in sorghum [Sorghum bicolor (L.) Moench]

Abstract

An investigation was carried out to assess the efficiency of A2 CMS system in comparison to the widely used A1 cytoplasm in sorghum for use in hybrid breeding programs at International Crops Research Institute for the Semi-Arid Tropics, Patancheru, Andhra Pradesh, India during 2002 and 2003 post rainy seasons. Significant cytoplasm effects on gca effects of A-lines and on mean performance and sca effects of hybrids were detected in only some of the nuclear genetic backgrounds and where detected, the magnitude of effects varied with the trait and was minimal to have any practical significance for any of the traits. The mean days to 50% flowering, plant height and grain yield of A2 cytoplasm-based hybrids were comparable with those of widely used A1 cytoplasm-based hybrids. The implications of these results are discussed in relation to opportunities for broadening cytoplasm as well as nuclear genetic base of sorghum hybrid parents.