Abstract

Cotton is cultivated in Iran with diploid and tetraploid forms and hybridization is a means to increase the genetic diversity and obtain new elite cultivars in this crop. This present study considered the molecular genetic diversity in Mehr (Gossypium hirsutum) cotton cultivar and its crossing progenies. 21 of 30 random amplified polymorphic DNA (RAPD) primers produced 220 reproducible bands with average of 10.47 bands per primer and 80.12% of polymorphism. OPR02 primer showed the highest number of effective allele (Ne), Shannon index (I) and genetic diversity (H). Some of the cultivars had specific bands, for example the F1 progeny of Mehr X No. 200, Mehr parental genotype and Mehr X Belilzovar hybrid genotype. Results show that some RAPD bands were present in the F1 progenies, but absent in the parental genotypes.  Some others were present in the parental genotypes, but were absent in their hybrids. The highest values of genetic diversity in RAPD markers were obtained in Mehr X Sindose and Mehr X Belilzovar hybrids. Nine of ten inter simple sequence repeats (ISSR) primers used produced 113 reproducible bands with average of 54.35% polymorphism. UBC834 locus revealed the highest number of Ne, I and H values. Also, some ISSR bands occurred only in the parental genotype while some others occurred only in the hybrid genotypes. The highest values of genetic diversity in ISSR markers were obtained in Mehr X Sindose and Mehr X Belilzovar hybrids.

Key words: Cotton, genetic diversity, random amplified polymorphic DNA (RAPD), inter simple sequence repeats (ISSR).