CHROMOSOME PAIRING AND HETEROZYGOTETRANSLOCATION IN&

A cytogenetic study was performed on 11 tetraploid cotton cultivars (Gossypium hirsutum L.) including the Oltan cultivar and its crossing progenies. The chromosome pairing and chiasma frequency, as well as meiotic abnormalities were compared among the genotypes studied. Heterozygote translocations with alternate orientation were observed between some of the chromosomes of the A genome and those of D genome in some of the cultivars, which may bring about new genetic rearrangement to be used in breeding programs. Meiotic abnormalities including formation of laggard chromosome, stickiness, as well as disorganized chromosomes occurred in some of the cultivars, which may cause pollen sterility. B-chromosomes were observed in some of the cultivars. The cultivars studied differed significantly in their cytogenetic characteristics, partly indicating their genomic differences, which may be used in cotton breeding.