Agronomic potential of A4(M) cytoplasmic male-sterility system compared to A1 CMS system of sorghum (Sorghum bicolor)

Abstract

An investigation was carried out to compare the A4(M) CMS (cytoplasmic-nuclear male-sterility) system to the widely used A1 CMS system in sorghum (Sorghum bicolor (L.) Moench) for agronomic traits and panicle grain mold resistance (PGMR) score at International Crops Research Institute for the Semi-Arid Tropics (ICRISAT), Patancheru, Andhra Pradesh, India in 2006 and 2007 rainy and postrainy seasons. The cytoplasm per se and its first order interaction with A-line seemed to contribute to grain yield, male-fertility restoration % and PGMR during rainy season and male-fertility restoration per cent during postrainy season. The mean days to 50% flowering, plant height and grain yield of A4(M) cytoplasm-based hybrids were comparable with those of A1 cytoplasm-based hybrids during 2006 and 2007 postrainy seasons while during 2006 rainy season, A4(M) cytoplasm based hybrids in few nuclear backgrounds were significantly superior to A1 cytoplasm based hybrids for early flowering and grain yield, while in few nuclear backgrounds A1 cytoplasm-based hybrids were superior. However, the A1 cytoplasm based hybrids were more tolerant for grain mold. Hence the A4(M) cytoplasm can be used to incorporate genetic diversity in grain sorghum hybrids for grain yield in postrainy season, but its use in rainy season is not recommended, where grain mold poses a problem.