Cotton (Gossypium hirsutum L.) characterization revealed small chromosomes with weak morphological differentiation; therefore, the translocation lines application necessitated its identification. In this study, a unified identification of chromosomes involved in exchanges took place for three translocation lines from the Uzbek cotton сytogenetic collection via translocation tester lines from the USA. Chromosome homology evaluation was according to the meiotic configurations at metaphase-I (MI) in pollen mother cells. Analysis of cotton F₁ hybrids obtained through crosses between translocation lines from two different collections revealed the involvement in translocation of several chromosomes in various lines. These are chromosomes 3 and 6 of the A_t-subgenome of cotton in line Tr8, in line Tr15, chromosome 6 of the A_t-subgenome and chromosome 14 of the D_t-subgenome, and in line Tr16, chromosomes 2 and 3 of the A_t-subgenome. The study also identified the homology of one of the translocated chromosomes in four translocation lines by crossing with tester lines. In two lines, Tr5 and Tr9, the detection of homology was with chromosome 6 of the A_t-subgenome, whereas in two other lines, Tr13 and Tr26, the established homology was with chromosome 3 of the A_t-subgenome.

Keywords: cotton (G. hirsutum L.), crossing, Uzbek cotton cytogenetic collection, translocated chromosomes, chromosome identification, translocation tester set

Key findings: Cytogenetic analysis of the cotton (G. hirsutum L.) F₁ hybrids revealed that in the Tr8 translocation line, chromosomes 3 and 6 of the A_t-subgenome of cotton showed involvement in the translocation; in the Tr15 line, the involved ones were chromosome 6 of the A_t-subgenome and chromosome 14 of the D_t-subgenome; and in Tr16 line, involved chromosomes were 2 and 3 of the A_t-subgenome.