Genetic Analysis For The Fiber Quality Of The Generation From Gossypium Hirsutum L.and Gossypium Barbadense L.Backcross

The cotton fiber traits which controlled by multi-gene and effected by environment, are quantity traits. The cotton fiber quality beween Gossypium hirsutum L. and Gossypium barbadense L. has marked difference. It is slowly for improving the cotton fiber by conventional breeding, and hard to meet the demand of production and market.This article is based on the179(BC4F2) backcross generation descended from Xi9upland cotton as the recurrent parent and Xinhai16sea island cotton as non-recurrent parent. At first we would optimize the system of SSR-PCR reaction. By doing many experiments, we obtained the best optimized system and procedure of SSR-PCR reaction. So we began to select the polymorphism SSR by using them to amplify between cotton parents. After that, we had accumulated many selected ploymorphism SSR primers to amplify among179cotton offspring (BC4F2). We got lots of effective marker data by doing many experiments. Connected with8fiber quality traits, we had analyzed the fiber traits of the generation with correlation analysis, principal components analysis and genetic multiformity analysis.These are the conclusions:1.8fiber quality traits of the backcross generation had been tested. By analyzed the mean, coefficient of variation, Skewness and Kurtosis, the reaults revealed these traits of the offspring appeared normal distribution, because Skewness all less than1, and the absolute value of Kurtosis except elogation others less than I. Owing to this, we deduced this generation is an ideal group for genetic mapping. By coefficient of variation analysis, we saw the value of short fiber index and microlone are the largest than the others. They revealed they are easy to be affected by different surroundings. Further study, by correlation analysis and principal components analysis, we obtained fiber length had pole marked positive correlation with SCI, marked positive correlation with STR, pole marked negative correlation with SFI.We found the value of the cumulate variance of first three principal components is81.65%, almost represented the information of the whole. Utilizing the special vector and score of first three principal components (1,2,3), the further result dismayed that the most difference between the fiber quality traits manifested the length, maturity, fiber thin and the ability of resistibility. Utilizing the value of three principle components to be clustering, we obtained three groups at the distance3.93. It is consistent with the analysis of three principle component.2. During the process of optimizing the system of SSR-PCR reaction, we selected three parameters which were the dosage of DNA, the anneal temperature of primers and consistence of Mg2+to optimize. Then we obtained the optimized system and procedure of SSR-PCR reaction. It was so important that the following work such as selecting the polymorphism SSR could not continue without it. We screened373pairs of SSR markers from total600pairs of SSR markers in parents’and obtained173pairs of SSR markers from373pairs in the offspring. According to the data we had accumulated about the polymorphism SSR, finally we made use of the system clustering to analyze the genetic effect. The result we had that at similar coefficient0.49, this generation was classified to three groups.3. After being sure the optimized system and procedure of SSR-PCR, conbining with the data of the polymorphism SSR, we acquired this method of the backcross between Gossypium hirsutum L.and Gossypium barbadense L. was one of effective methods for improving the quality of the upland cotton fiber.