陆地棉遗传图谱构建与纤维品质性状QTL定位

Genetic Map Construction and QTL Mapping of Fibre Quality in Upland Contton (Gossypium hirsutum L.)

以陆地棉（Gossypium hirsutum L.）品种Bar19/1和Acala 1517-77杂交的108个F2单株为材料,应用85个标记（70个SSR标记和15个AFLP标记）构建了总长为814 cM的遗传图谱,覆盖棉花基因组的18.3%.该图谱包含25个连锁群,分别对应到17条染色体和4个未知连锁群.应用复合区间作图法分析了该组合的108个F2单株和F3家系纤维品质性状,从遗传图谱上检测到19个纤维品质数量性状基因座（QTL）,包括5个纤维长度、6个纤维比强度、4个伸长率及4个马克隆值QTL,分别解释各性状表型变异的15.11%～28.45%、8.46%～24.51%、11.08%～27.55%和9.23%～42.21%.纤维长度和伸长率的QTL以部分显性为主,少数具有超显性,比强度QTL以加性和部分显性为主,4个马克隆值QTL中有3个表现为超显性.研究结果表明,陆地棉Bar19/1和Acala1517-77间多态性位点丰富,有利于构建高密度遗传图谱,纤维品质性状的QTL分析从分子水平上揭示了纤维品质的遗传基础.

108 F2 plants in the cross of two cotton varieties,Bar19/1 and Acala 1517-77 were chosen to construct the genetic map,which had a whole length of 814 cM and covered 18.3% of the geneome of cotton, with 85 markers （70 SSR markers and 15 AFLP markers）. The map contained 25 linkage groups that separately corresponded with 17 chromosomes and 4 unkown linkage groups. The fibre characteristics of the 108 F2 plants and the F3 family lines were analysed by composite interval mapping and 19 quantitative trait loci of fibre quality were identified in the genetic map and these traits involved the QTLs of 5 fibre lengths, 6 fibre strengths,four fibre elongations and four fibre micronaires ;The QTLs sparately explained 15.11% -28.45% ,8.46%-24.51% ,11.08%-27.55% and 9.23%-42.21% of the phenotypic variations in the four traits. Of the QTLs in fibre length and elongations,a majority appeared partially dominant and a minority appeared superdominant,the QTLs in fibre strength mainly appeared additive or partially dominant and of the QTLs in the four micronaires,three appeared overdominant. The results showed that there were rich polymorphic sites between Bar19/1 and Acala 1517-77,which were favourable for the genetic map construction and the QTL analysis of the fibre traits revealed the genetic basis of fibre quality at molecular level.