棉花分子遗传图谱构建和纤维品质性状QTL分析

Construction of Molecular Genetic Map and QTL Analysis of Fiber Quality in Cotton

以陆地棉(Gossypium hirsutum L.)中棉所8号和海岛棉(Gossypium barbadense L.)Pima90-53组配衍生的214个单株的F2群体为材料,构建了包含110个SSR标记和65个AFLP标记的遗传连锁图谱。该图谱共包括42个连锁群,连锁群长度为4.5～147.3cM,包括2～22个分子标记,标记间平均距离为11.6cM,总长为2030cM,约占棉花全基因组的40.6%。应用复合区间作图法分析该组合的F2单株和F2:3家系纤维品质性状,共得到25个纤维品质数量性状基因座(QTL),其中5个与纤维长度相关,分布在Chr.21、Chr.15、LG2和LG12上,可解释表型变异的10.2%～35.8%;4个与整齐度相关,分布在Chr.21、LG9、LG18和LG12上,可解释表型变异的12.6%～36.6%;7个与马克隆值相关,分布在Chr.9、LG1、LG9、LG20和LG12上,可解释表型变异的11.5%～26.1%;7个与断裂比强度相关,分布在Chr.21、Chr12、Chr.8、LG1、LG4和LG10上,可解释表型变异的16.5%～52.8%;2个与伸长率相关,分布在Chr.9和Chr.21上,可解释表型变异的18.1%和27.1%。LG9、LG12和Chr.21上存在QTL聚集区。

Cotton is a leading textile fiber crop in the world and a source of secondary products such as oil, live-stock feed （cot-ton seed cake） and cellulose. The improvement of cotton fiber quality is becoming extremely important with the innovation of spinning technology. A genetic map is necessary not only for the reliable detection, mapping and estimation of gene effects of important agronomic traits, but also for further research on the structure, organization, evolution and function of cotton genome. In the present study, simple sequence repeats （SSRs） and amplified fragment length polymorphism （AFLP） were used to assay an F2 population from a cross between CRI8 （Gossypium hirsutum L.） and Pima 90-53 （Gossypium barbadense L.）. Two hundred and fourteen F2 plants were used for map construction using 110 SSRs and 65 AFLPs. This map included 175 markers distributing on 42 linkage groups, covering 2 030 cM, accounting for 40.6% of the cotton genome, and with an average distance of 11.6 cM be-tween two markers. The length of linkage groups ranged from 4.5 to 147.3 cM and the markers on the groups ranged from 2 to 22. The linkage map was located on 10 chromosomes, which were Chr.4, Chr.8, Chr.9, Chr.10, Chr.12, Chr.14, Chr.15, Chr.18, Chr.21, and Chr.25. Based on composite interval mapping, five QTLs were identified for fiber length, distributing on Chr.21, Chr.15, LG2, and LG12, explaining 10.2-35.8% of the fiber length variance. Four QTLs were identified for length uniformity, distributing on Chr.21, LG9, LG18, and LG12, explaining 12.6-36.6% of the fiber length uniformity variance. Seven QTLs were identified for micronaire, distributing on Chr.9, LG1, LG9, LG20, and LG12, explaining 11.5-26.1% of the fiber micronaire variance. Seven QTLs were identified for strength, distributing on Chr.21, Chr.12, Chr.8, LG1, LG4, and LG10, explaining 16.5-52.8% of the fiber strength variance. Two QTLs were identified for fiber elongation, distributing on Chr.9 and Chr.21, explaining 18.1% and 27.1% of the fiber elongation variance. Assembled section of QTLs existed in LG9, LG12, and Chr.21. The present map and QTL analysis may provide a useful tool for breeders to transfer desirable traits from G. barbadense to the mainly cultivated species, G. hirsutum.