Cyto-Geneticy evaluation of back-crossed genotypes derived from Iranian endemic cottons with Arboreum species

This study was carried out in order to investigate on chromosomal behavior during meiosis in herbaceum (Iranian endemic), arboretum species, F1 hybrids of two species and BC4 genotypes. The endemic varieties used in this study were semnan and shahreza (herbaceum) and VTDL as arboretum cultivar. F1s investigations showed that in the adjacent and alternative quadrivalents frequently but the BC4 offspring population the quadrivalents were appeared in low frequency. Besides, other abnormalities like univalent, trivalents and triple sets of chromosomes in MII and AII were observed which was resulted in the deviation from Tetrads. Repeated back-crosses caused to reduce the irregularities, as most of the plants showed normal behavior of meiosis. Since simultaneously breeding for all traits, especially through far hybridization, is not possible at one stage, so the resulted offspring would be great achievement at the early steps of endemic cotton improvement.