Features of Chromosome Introgression from Gossypium barbadense L. into G. hirsutum L. during the Development of Alien Substitution Lines

The creation of G. barbadense L./G. hirsutum L. chromosome-substitution lines is an important method to transfer agronomically valuable traits from G. barbadense into G. hirsutum. In this study, 30 monosomic lines of G. hirsutum from the Cytogenetic Collection of Uzbekistan, created in the genotypic background of line L-458, were used in crosses with the G. barbadense line Pima 3-79 to create substitution lines. In the course of this work, new monosomic lines were identified for chromosome 12 and monotelodisome 6 of the A(t)subgenome and for chromosomes 17, 21, and 22 of the D(t)subgenome using chromosome-specific SSR markers and a well-defined tester set of cotton translocation lines (USA). Compared to those in the F(1) hybrids, a strong decrease in the crossing and setting rates was found in the BC(1)F(1) backcross lines, with the substitution of chromosomes 2, 4, 6, 7, and 12 of the A(t)subgenome and 17, 18, 21, and 22 of the D(t)subgenome. The F(1) and BC(1)F(1) offspring from interspecific crosses differed in their transmission of univalents. Despite the regular pairing of chromosomes and the high meiotic index, interspecific aneuploid hybrids were characterized by a decrease in pollen fertility, which may indicate hidden structural variability in these genomes that did not affect meiotic division. The identification of chromosomes using chromosome-specific SSR markers in the early stages of plant development has greatly accelerated the detection of monosomic plants. The analysis of morphobiological traits revealed that monosomic F(1) hybrids were more similar to the donor line, while BC(1)F(1) hybrids were more similar to the recurrent parent but also showed previously undetected traits.