Study of the influence of introgression from chromosome 2 of the At subgenome of cotton Gossypium barbadense L. during backcrossing with the original lines of G. hirsutum L
Аннотация
The creation of chromosome substitution lines containing one pair of chromosomes from a related species is one method for introgression of alien genetic material. The frequency of substitutions in different chromosomes of the genome varies due to the selective transmission of alien chromosomes through the gametes of hybrids. The use of monosomic lines with identified univalent chromosomes and molecular genetic SSR markers at the seedling stage allowed rapid screening of the identity of the alien chromosome in backcross hybrids, significantly accelerating and facilitating the backcrossing process for the creation of new chromosome substitution cotton lines. As a result of studying the process of transmission of chromosome 2 of the At subgenome of the cotton plant G. barbadense L. during backcrossing of four original monosomic lines of G. hirsutum L. with monosomic backcross hybrids with substitution of chromosome 2 of the At subgenome, the following specific consequences of the introgression of this chromosome were revealed: decreased crossability, setting and germination of hybrid seeds; differences in the frequency and nature of transmission of chromosome 2 of the At subgenome of the cotton plant G. barbadensе; regularity of chromosome behavior in meiosis; a high meiotic index; a significant decrease in pollen fertility in backcross monosomic hybrids BC1F1; specific morphobiological characteristics of monosomic backcrossed plants, such as delayed development of vegetative and generative organs; dwarfism; reduced foliage; and poor budding and flowering during the first year of vegetation. All of these factors negatively impact the study and backcrossing of monosomic hybrids and significantly complicate and delay the creation of chromosome-substituted forms concerning chromosome 2 of the At subgenome of cotton, G. barbadense. These specific changes likely occurred as a result of hybrid genome reorganization and introgression of alien chromatin. Furthermore, the effectiveness of using molecular genetic microsatellite (SSR) markers to monitor backcrossing processes and eliminate genetic material from the Pima 3-79 donor line of G. barbadense for the selection of genotypes with alien chromosome substitutions has been demonstrated.