QTL Analysis Of Fiber Yield And Quality Using Gossypium Hirsutum×G. Barbadense Advanced Backcross Populations

In order to introgress elite QTL alleles of G.barbadense L.for fiber yield and quality into G.hirsutum L.and enlarge the narrow genetic base of G.hirsutum and provide more new germplasm resources for the variety development,the commercial G.hirsutum variety 'Zhongmiansuo36' and G.barbadense 'Hai 1' were respectively used as recurrent and donor parent to produce backcross populations,including BC₁F₁, BC₁S₁ and BC₂F₁.QTL analysis of yield-related trait and fiber quality on three phenotypic data sets were proceeded by the Composite Interval Mapping method.A total of 3223 SSR primer pairs were used to screen polymorphism among the parents Zhongmiansuo36,Hai 1 and their F₁ progeny,which resulted in 294 polymorphic primer pairs with the special band for Hai 1,and 264 of them were used to screen the BC₁F₁ population.Linkage test indicated 217 of 277 polymorphic locus derived from 264 primer pairs could be mapped into 44 linkage groups and covered a total genetic distance of 1908.67cM,approximately 42.89%of cotton genome.The number of the markers per linkage group was 27.46,which spanned 43.38cM of the cotton genome.And the average distance of the neighboring markers were 8.80cM.9 QTLs for yield-related traits were mapped among the three generations using CIM.QTL numbers for lint percentage,boll weight and seed index were 2,5 and 2, respectively,which accounted for 6.90%～19.17%of phenotypic variance.2 QTLs for lint percentage could be detected in the three generations,which indicated that these QTLs had stable genetic effect under different genetic backgrounds and could be used for marker-assisted selection.30 QTLs for fiber quality traits were mapped among the three generations.QTL numbers for fiber length,strength,micronaire,uniformity and elongation ratio were 7, 8,3,4,8,respectively,which could explain 6.62%～15.38%of phenotypic variance. Two QTLs for fiber length could be detected in the three generations.Additionally, one for fiber length and one for fiber strength could be detected in both BC₁S₁ and BC₂F₁.