Analysis On The Major Gene And Multigene Mixed Inheritance And QTL Mapping For Early Maturity Traits In Upland Cotton

Earliness traits of upland cotton are quantitative traits influenced by genotype and environment. We used 2 upland cotton(zhong751213 and lumianyan28) to construct segregating populations that be used in analysiing the genetic of earliness traits in upland cotton. Using GBS constructed genetic linkage map and QTL for earliness traits. The main results were as follows: 1、 Traits related to earliness traits are very important for the upland cotton. In this paper, inheritance of 6 earliness traits was analyzed by the joint segregation analysis of a mixed genetic model of major gene plus polygene in five generations(P1, P2, F1, F2, and F2:3) derived from Zhong751213×Lumianyan28. The results showed that earliness traits were not only controlled by major gene, but also by minor effect polygene. There was one major gene at least expressing at different growth and development stages. In the upland cotton of different developmental stages, the main role of gene regulation vary. Influenced by the environment, separate groups in the same trait heritability differences. Whole growth period in the F2, F2:3 populations genetic rate are 91.275%, 90.953% respectively. The genetic stability is less affected by the environment, so the whole growth period can be chosen as an important marker for early maturity traits of cotton. 2、 Zhong751213, a short season cotton, and lumianyan28 were used to create 170 F2 and F2:3 segregating population in Anyang. With GBS, the two parents were used to screen 5747 SNP markers.2382 bin markers(3903 SNP markers) were used in linkage map construction and covered 26 chromosomes. Each chromosome contains 34-340 SNP markers and the length of chromosome range from 55.19 c M to 439.31 c M. The average minimum distance between two markers is 0.54 c M and the max is4.53 c M. The total length is about 4570.19 c M, covering 91% of the whole cotton genome. 76 QTLs were found in two segregating population. More than 15% phenotype variance was explained by 14 QTLs, two in F2 population and the others in F2:3 population. 3、 Genetic analysis and QTL mapping for earliness traits showed that not all synergistic gene from high value parent, but also from low value parent. In the breeding work, we need to make full use of the favorable genes in high value parent, also not ignoring the low value parent the test results with the practical breeding to improve earliness traits in upland cotton.