Molecular characterization of genetic male sterile genotypes in diploid cotton (Gossypium arboreum) and development of male sterility specific SCAR marker

Genetic male sterility (GMS) in the Gossypium arboreumwas found to be under the control of recessive gene. This GMS system has been used for diploid cotton hybrid breeding in India. In the present study, RAPD marker was used to characterize the Hisar GMS and SRT-1GMS lines which are derived from the repeated back crosses. Male sterility in these genotypes is governed by the single recessive gene ams-j. From the survey of 60 random decamer primers, 34 were found to be polymorphic generating 60.73 per cent polymorphism between male sterile and male fertile plant. Out of the polymorphic primers OPAB3, OPAB4, OPAB5, OPAB19, OPH20, OPI2, OPI3 and OPI7 showed a notable differences in the amplicon profile of male sterile and their fertile counterparts. Dendrogram revealed two distinct clusters in which all the male sterile and fertile plants made independent clusters indicating genetic differences between them for sterility. The primer OPI3 was found to be male sterile specific in repeated PCR by consistently producing a specific fragment of 486 bp only in the sterile plants which has been later converted into an locus specific Sequence Characterized Amplified Regions (SCAR) marker. The RAPD markers associated with male sterility and putative SCAR marker specific to male sterility may facilitate for the utilization of the GMS system inhybrid breeding in the Asiatic cotton.