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利用分子标记技术,在许多作物上已获得了高密度的分子遗传图谱,并定位了许多主要农艺性状的QTL,而在牧草上这方面的研究尚属空白。为提高育种中对牧草产量性状优良基因型选择的效率,对高丹草的单株产量及其构成因素(株高、分蘖数、叶片数)进行QTL定位,确定其在染色体的位置及其遗传效应,探讨其杂种优势产生原因。在以高粱413A和棕壳苏丹草杂交获得的248个F2:3家系构建的作图群体中,应用AFLP和RAPD两种标记技术构建了高丹草(Sorghum×Sudan grass)的遗传连锁图谱。共包含168个标记,分布于10个连锁群,图谱总长度为836 cM,标记间平均图距为4.98 cM。采用Joinmap/QTL4.0对高丹草单株产量及其三大构成因素进行QTL定位。共检测到QTLs19个,分布在8个连锁群上,其中,第1和3连锁群最多,各为4个和3个。单个QTL解释性状表型变异的5.20%～51.50%。检测到的19个QTL中,表现加性效应的有1个,占5.26%,部分显性效应的有3个,占15.79%,显性效应的有6个,占31.58%,超显性效应的有9个,占47.36%。超显性效应和显性效应在高丹草杂种优势的遗传基础中占主导地位。
Using molecular marker technology, high-density molecular genetic maps have been obtained on many crops and many QTLs for major agronomic traits have been mapped, but research on forage grass is still blank. In order to improve the efficiency of genotypic selection of forage yield traits in breeding, the QTL mapping of per plant yield and its components (plant height, tiller number and leaf number) of Sorghum sudanense was conducted to determine its position on the chromosome and its genetic Effect, to explore the causes of its heterosis. A genetic linkage map of Sorghum × Sudan grass was constructed using AFLP and RAPD markers in a mapping population of 248 F2: 3 lines obtained from cross between sorghum 413A and S. sudanense. A total of 168 markers were distributed in 10 linkage groups with a total length of 836 cM and a mean distance between markers of 4.98 cM. Joinmap / QTL4.0 was used to determine the QTL mapping of the Sorghum bicolor plants per plant and their three major components. A total of 19 QTLs were detected and distributed in 8 linkage groups, of which, the first and third linkage groups were the most, which were 4 and 3 respectively. A single QTL explained phenotypic variation of 5.20% ~ 51.50%. Among 19 detected QTLs, 1 showed additive effect, accounting for 5.26%, 3 partially dominant effect, accounting for 15.79%, dominant effect 6, accounting for 31.58%, and overdominant effect There are 9, accounting for 47.36%. The super dominant effect and dominant effect dominates in the genetic basis of Gordian germplasm heterosis.