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

Abstract

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 Atsubgenome and for chromosomes 17, 21, and 22 of the Dtsubgenome using chromosome-specific SSR markers and a well-defined tester set of cotton translocation lines (USA). Compared to those in the F1 hybrids, a strong decrease in the crossing and setting rates was found in the BC1F1 backcross lines, with the substitution of chromosomes 2, 4, 6, 7, and 12 of the Atsubgenome and 17, 18, 21, and 22 of the Dtsubgenome. The F1 and BC1F1 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 F1 hybrids were more similar to the donor line, while BC1F1 hybrids were more similar to the recurrent parent but also showed previously undetected traits.