Construction Of Genetic Linkage Map And QTL Mapping Of Lint Percent In Upland Cotton Intraspecific Population

As the world’s most widely cultivated fiber crop, cotton occupies an irreplaceable status in the development of national economy. The genus Gossypium comprises approximately 45 diploid and 5 tetraploid species. Cultivated species include two diploids G. herbaceum L. and G. arboreum L., and two tetraploids G. hirsutum L. and G. barbadecse L.. Of these, upland cotton(G. hirsutum L.) dominates the production of cotton fiber, and reaches up to about 95% of the world’s total production.Up to now, increasing cotton production still has been an important goal in cotton breeding because the yield per area reaches a new plateau. Great advance in molecular marker technologies make it possible for breeders to find a rapid and precise alternative approach to conventional breeding selection schemes.G. hirsutum races, also known as semi-wild cotton, have many superior characteristics, such as disease resistance, salinity, large boll, high lint percent etc. which are cultivars lacking. Gossypium races species is very close to upland cotton cultivar and the cross among them can produces genetic fertile hybrid. Therefore, G. hirsutum races provide very valuable germplasm resource for cotton breeding.The present study selected high fiber quality upland cotton cultivar Yumian 1 and G. hirsutum race latifolium accession TX43 to establish(Yumain 1×TX43) F2 population. An upland cotton intraspecific genetic map was constructed and lint percent QTL was identified. The results are as following:1. The polymorphic primers between mapping parentsIn total, 7862 SSR primer pairs were used to screen the polymorphic primers between Yumian 1and TX43, and 193 polymorphic primers were obtained. The polymorphic primers accounted for 2.5% of total primers.2. Construction of genetic mapThe 193 polymorphic primers were used to genotype(Yumian 1 × TX43) F2 population, and 197 loci were obtained. The 197 loci were employed to perform the linkage analysis, and a linkage map including 38 groups was constructed. The map spanned 1367.9c M with an average distance of 9.86 c M between two markers.3. QTL mapping of lint percentageBased on the genetic map and the phenotypic data of lint percentage in two environments(in 2014 and 2015), four QTL for lint percentage were detected. These QTL explained phenotypic variation from 13.9% to 25.3%.