Genetic specifics of the breeding of cotton varieties with cleistogamous flowers
Аннотация
As a prerequisite to studying the genetics and breeding of chasmogamous and cleistogamous flowers, a preliminary experiment was performed to estimate the extent of cross-pollination in cotton varieties and hybrids. Vicinism estimates varied from 0.53 to 15.36%, i.e., the proportion of cross-pollination was relatively high, leading to a biological contamination. As a result of such contamination, genetic collection lines and varieties lose genetic homogeneity and become heterozygous and genetically heterogeneous. The genetic control of the flower type was studied in the Gossipium hirsutum L. × G. barbadense L. interspecific hybrids, and phenotypic segregation of the 3: 1 and 15: 1 types with monogenic (3: 1) and digenic (15: 1) differences of noncumulative polymerization was observed. The corresponding types of genotypic segregation were 1: 2: 1 (1Cg 1 Cg 1 cg 2 cg 2 : 2Cg 1 cg 1 cg 2 cg 2 : 1cg 1 cg 1 cg 2 cg 2 ) and 1: 2: 2: 4: 1: 2: 1: 2: 1 (1) Cg 1 Cg 1 Cg 2 Cg 2 -1; (2) Cg 1 Cg 1 cg 2 cg 2 -2; (3) Cg 1 cg 1 Cg 2 Cg 2 -2; (4) Cg 1 cg 1 Cg 2 cg 2-4; (5) Cg 1 Cg 1 cg 2 cg 2 -1; (6) Cg 1 cg 1 cg 2 cg 2 -2; (7) cg 1 cg 1 Cg 2 Cg 2-1; (8) cg 1 cg 1 Cg 2 cg 2 -2; (9) cg 1 cg 1 cg 2 cg 2 -1. Genotypes (1)–(8) had chasmogamous flowers, while double-recessive genotype (9) had cleistogamous flowers. Based on this, genotypes with individual phenotypic expression were identified in F2, and their correlation with the most important morphological, biological, and agricultural features was studied. Special attention was paid to the productivity of hybrid plants intended for use in breeding to obtain intensive varieties. The study made it possible to isolate forms, families, genetic collection lines, and varieties with isogenic or nonisogenic determination of these characters and chasmogamous and cleistogamous flowers of G. hirsutum L. and G. barbadense L. prototypes by using original methods to examine the two types of flowers; the methods do not have analogs in cotton breeding worldwide.