Cytomorphology of interspecific hybrids between Gossypium hirsutum L., its haploid and Gossypium raimondii

Abstract

Interspecific hybrids between G. hlrsutum, its haploid and G. ralmondll were obtained. Morphological studies of different characters indicated that flower colour, petal spot, filament colour, pollen colour, stems, leaf hairiness etc. of G. ralmondll were found to be dominant In both the hybrids while other growth characters and habit were intermediate. Meiosis in G. hlrsutum and G. ralmondll was normal leading to formation of viable pollen, however, in haploid and both the hybrids it was abnormal. On an average chromosome associations at diakinesis and metaphase-I were 4.11 1 + 4.6911 + 4.17111 and 5.301 + 4.2011 + 4.10111 and 10.5511 + 10.2711 + 1.13111 + 1.131V and 10.291 + 10.9911 + 1.39111 + 0.64IV, in diploid (G. hlrsutum haploid x G. ralmondll) and triploid (G. hlrsutum x G. ralmondll), hybrids, receptively. Further, 4 to 6 bivalents observed in hybrid between G. hlrsutum haploid x G. ralmondll were due to pairing between. Ah 05 chromosome of G. hlrsutum and G. ralmondJl, respectively and also Ah with 0h and 05 chromosomes. In addition, bivalents formed in diploid hybrid and trivalent and quadrlvalents In triploid hybrid due to pairing between non-homologous chromosomes. Pattern of chromosome pairing indicated that chromosomes from 05 genome of the G. ralmondll have closer homology with Ah 0h' chromosomes of G. hlrsutum. Formnation of multivalents, univalents and unequal separation of chromosome has resulted in formation of sporads containing 1-7 spores leading to formation of sterile pollens with high size variation.