Study On Heredity Of Fiber And Genetic Diversity Of The Colored Cotton

The colored cotton is a kind of cotton with the natural color in its fiber. Along with the idea of health and the environmental protection sinking deep into the hearts of people, the colored cotton development and using is a tidal current. The germplasm with poor quality traits has not played the important role in the textile production. Recently, domestic and foreign breeders lanuched the colored cotton breeding, and have got a lot of elite germplasm with stable traits, which have enlarged the genetic base on the colored cotton. Its agronomic characters have made distinct enhancement, but have not obtained the crucial breakthrough. The research of the inheritance rules of it is not thorough and consistent. And the paper of study on the colored cotton germplasm is rare. The factors restrict the development of the colored cotton. Therefore, F₂ population of different combination and 61 lines of colored cotton were collected in our reserch. The purpose of this paper was to make a thorough analysis of the inheritance rule of Brown fiber and evaluate the genetic diversity and the effect enhancement of the colored cotton lines coming from different country and different provinces and select the germplasm which have better value in application, so as to accelerrate the aplication in the colored cotton breeding. At the same time, according to the process of the flavornoids synthesis and EST (expressed sequnced tags:) or cDNA of the key anthecyanin gene, Specific marker were designed to rich existing molecular markers. The results showed as following:1) A thorough analysis of the inheritance rule of Brown cotton fiber was been made using F₂ population of different combination, and the viewpoint of the colored lint and colored fuzz of Brown cotton controlled by the two pairs major genes incomplete dominance on non-homologous chromosomes, respectively, were proposed for the first time. While white lint and fuzz were dominant to brown ones, respectively. There exists interaction between lint and fuzz coloring gene, and the genetic modle also was been established.2) Regarding brown 128 and FB20 as parents, F₂ as maping populations, we used SSR technology to tag Brown lint gene, the 1 out of 15 pairs were linked with the brown lint gene, and their distance was 18.4 cM.3) By evaluating important agronomic characters of the 61 colored cottons, 26 elite germplasm with sole elite quality traits were been obtained. We found that the linesdeveloping by the method of hybridization breeding had more enhacement than breeding by the selection. Utilization of induce mutation and the biochemistry was helpful to improvement of fiber quality and developing the new lines. The fiber quality of the colored cotton developing in recent years between Borwn cotton and Green cotton had not obviously distinctness.4) 61 the colored cotton lines, inculding 40 Brown cottons and 21 Green cottons were used to analyze genetic variation at 66 SSR loci. A total of 344 alleles were detected, in which 340 and 321 alleles occurred in 40 Brown cottons and 21 Green cottons. Respectively. The average number of allele's perlocus was 4.9 for Green cottons and 5.2 for both all the colored cotton and Brown cottons. It is suggested that the genetic diversity of Brown cotton was lower than the colored cotton, but higher than Green cotton.5) According to the process of the flavornoids synthesis and the EST (expressed sequnced tags) or cDNA of the key anthecyanin gene, 31 pairs specific marker were designed to rich existing molecular marker. The PCR results amplified by the 31 pairs specific marker showed that 27 pairs of it have amplified sequncene, and 8 pairs have ploymorphism among diferent the colored cotton lines.