Cytogenetic and molecular genetic studies of the cotton haploid describe its morpho-biological features in comparison with the parental genotypes. This research aimed to study the cotton haploid (277₂) spontaneously developed through interspecific crossing of monosomic line Mo15 (Gossypium hirsutum) with Pima 3-79 (G. barbadense) to create the chromosome-substituted cotton lines. With species incompatibility, selective elimination of chromosomes took place in one of the parental genomes observed in interspecific hybrids. The haploid plant displayed characteristics of a thin and tall stem, dense foliage, shortened internodes, small three-lobed leaves, and complete sterility. In the metaphase I of meiosis, 26 univalents manifested random distribution in the pollen mother cells. The haploid stood out by the complete absence of bivalent formation and presence of unpaired chromosomes in the pollen mother cells. Molecular genetic analysis of the haploid using SSR markers revealed the alleles only from the species G. hirsutum in all 26 chromosomes of the haploid genome, which confirmed the selective elimination of chromosomes of the entire paternal genome. The promising results indicated the possibility of using haploid inbreeding by developing doubled haploids (DH).

Keywords: Cotton, Gossypium hirsutum, G. barbadense, monosomic line, haploid, selective elimination of chromosomes, SSR markers

Key findings: Cytogenetic analysis of the interspecific F₁ hybrid (277₂) obtained through crossing of the monosomic line Mo15 (G. hirsutum L.) with disomic line, Pima 3-79 (G. barbadense L.) appeared with morpho-biological features and complete absence of chromosome pairing. The SSR markers confirmed the presence of alleles only from the species G. hirsutum, indicating selective elimination of chromosomes.