Genetic Model And QTL Analysis Of Fiber Quality Traits In Upland Cotton Of XinJiang

Based on the data of field experiment of 6 generations (P₁, P₂, F₁, F₂, B₁, B₂) from the upland cotton cross (9-1696×Zhong35) and 13 SSR makers information of 180 plants of F₂ population and 135 plants of B₁ population, the inheritance of 4 fiber quality traits were studied by the methods of generation means, major gene-polygene mixed inheritance model, and QTLs . The major results are as follows:1. By the method of generation means, the heredity of fiber quality traits were mostly additive, as well as epistasis. Through Chi-Square Test, the traits of Fiber length and Enlongation expressed additive dominant and epistatic effects, and the traits of Strength and Uniformity expressed additive and epistatic effects.2. By the method of major gene-polygene mixed inheritance model, it was showed that Strength and Enlongation adapted to two major genes plus polygene model, and the major genes express additive dominant and epistatic effects. The major-genes hereditability were 47.80% of strength, 20.07% of enlongation. Fiber length and Uniformity were controlled by both major-gene and polygene.3. Six QTLs were detected and linked to four fiber quality traits by using F₂ population and interval mapping method (at the level of LOD>2). One QTL was linked to Fiber length, with distance 1.3 cM from marker H1511 and explaining 16.8% of the phenotypic variation; Three QTLs were linked to strength, the first with distance 5.2cM from marker H111, the second with distance 2cM from marker H103, and the third with distance 1.3cM for marker H1511. The three QTLs can explain 20.8%, 11.8%, 10.3% of the phenotypic variation, respectively; One QTL was linked to uniformity, with distance 2.2cM from marker H177 and explaining 16.8% of the phenotypic variation; One QTL was linked to elongation, with distance 2cM from marker H275 and explaining 18.9% of the phenotypic variation. Two QTLs were identified based on B₁ population, and linked to fiber length and strength respectively. One was linked to Fiber length, with distance 8cM from marker H161 and explaining 31.1% of the phenotypic variation, the other was linked to Strength, with distance 7cM from marker H111 and explaining 11.1% of the phenotypic variation. The marker H111 was linked to one major QTL for Strength by using a few QTL methods and two QTL populations.4. It is showed that the three methods of generation means, major gene-polygene mixed inheritance model, and QTLs can analyses the quality traits deeper and deeper, comparing the results of genetic variation by using the three methods. Meanwhile, the result from three methods can more and more help breeding working.