Karyotype and RAPD Diversity in Four Varieties of Gossypium hirsutum L.

抄録

Four recently released varieties of Gossypium hirsutum L. by Bangladesh Cotton Development Board (CDB) viz. CB-12, CB-13, CB-14, and Rupali-1 were studied cytogenetically and at the molecular level to elucidate the genomic diversity among the varieties. Although the four varieties were found to possess 2n=52 chromosomes, they differed in respect of karyotype formulae such as 48m+4sm in CB-12, 52m in CB-13, and 50m+2sm in CB-14 and in Rupali-1. Moreover, these varieties differed with respect to other karyotypic features such as total length of 2n chromosome complements, number of satellites, range of relative length, centromeric index, etc. Different number of satellites viz. two in CB-12 and Rupali-1 and four in CB-13 and CB-14, were found after only CMA-staining. CMA-fluoresced satellites of four cotton varieties suggest stain specificity. A wide range of CMA-positive bands were found in these four varieties. Out of four varieties no DAPI-positive band was found in CB-13 and Rupali-1. Fluorescence banding revealed genomic alteration and karyotype diversification within the four varieties. The five RAPD primers generated 53 bands with 90.56% polymorphism indacting diverse genomic nature. Two unique RAPD bands were found in Rupali-1 which could be used as markers. Therefore, each variety could be characterized by diverse karyotypes and molecular data.