CYTOPLASMIC MALE STERILITY AND INTER AND INTRA SUBGENOMICHETEROSIS STUDIES IN BRASSICA SPECIES: A REVIEW

Plants of the genus Brassica comprise a remarkably diverse groupof crops and encompass varieties that are grown as oilseeds, vegetables, condimentmustards and forages. One of the basic requirements for developing hybridvarieties in oilseed Brassica is the availability of proven heterosis. Thedevelopment of hybrid cultivars has been successful in many Brassica spp. Midparentheterosis and high-parent heterosis (heterobeltiosis) have extensively beenexplored and utilized for boosting various quantity and quality traits in rapeseed.Heterosis is commercially exploited in rapeseed and its potential use has beendemonstrated in turnip rape (B. rapa L.) and Indian mustard (B. juncea L.) for seedyield and most of the agronomic traits. The oilseed rape plant, B. napus, possessestwo endogenous male sterile cytoplasms, nap and pol. Ogura type of cytoplasmicmale sterility was first discovered in Japanese wild radish and other male-sterileBrassicas (Ogura bearing cytoplasm) derived from interspecific crosses.Information concerning the allelic frequencies of restorers can be useful in trying tounderstand their evolutionary origins. The ogu, pol and nap cytoplasms of B. napusinduce sterility in all, some, and only a few cultivars, respectively. In this study,different kinds of male sterility, combining ability and heterosis of qualitative andquantitative traits in different Brassica species will be reviеwed.