甘蔗SSR和AFLP分子遗传连锁图谱构建

Construction of Molecular Genetic Linkage Map of Sugarcane Based on SSR and AFLP Markers

采用甘蔗商业品种Co419与野生种割手密Y75/1/2杂交,获得269个单株,组成F1群体,用F102/356与商业品种ROC25回交获得266个单株,组成BC1群体。利用筛选的多态性条带丰富的36对SSR引物和12对AFLP引物,对两个群体进行PCR扩增和分子遗传连锁分析,构建甘蔗分子遗传连锁图谱。用F1群体获得630个分离标记,经χ2检测,298个标记为单双剂量标记,占总标记数的47%;用BC1群体获得571个分离标记,有264个标记为单双剂量标记,占总标记数的46%;4个亲本获得单双剂量标记的数量依次为Co419>02/356>Y75/1/2>ROC25。在LOD≥5.0,相邻标记遗传距离≤40cM的条件下,F1群体有134个单双剂量标记被纳入55个连锁群,其中39个连锁群归属8个同源组,16个未列入,总遗传距离为1458.3cM,标记间平均图距为10.9cM;BC1群体有133个单双剂量标记被纳入47个连锁群,其中34个连锁群归属于8个同源组,13个连锁群未列入,总遗传距离为1059.6cM,标记间平均图距为8.0cM。从4个亲本单双剂量标记进入的连锁群数来看,Co419最多,归入34个连锁群,其次为Y75/1/2,归入20个连锁群,第3为02/356和ROC25,归入19个连锁群。研究结果表明,从单双剂量标记比例、形成连锁群数量、总遗传距离来看,F1群体构图质量要优于BC1群体。

To take advantage of the MAS technique and develop the molecular genetic linkage map in sugarcane breeding program in China, we constructed two molecular genetic maps by single dose markers （SDM） and double dose markers （DDM） from 36 SSR and 12 AFLP primers for two mapping populations （F1 and BC1）. F1 population was from cross combination of sugarcane commercial variety （Co419） x S. spontaneum （Y75/1/2） consisting of 269 true individuals, BC1 population from backcross combination of F1 02/356×sugarcane commercial variety （ROC25） with 266 true individuals. All plants from two populations were detected by PCR. Two molecular genetic linkage maps were established. 298 SDMs and DDMs were acquired by χ^2 test from 630 segregation markers of F1 population, about 47% of total markers; 264 SDMs and DDMs were obtained from 571 segregation markers of BC1 population which were 46% of total markers, Co419〉02/356〉Y75/1/2〉ROC25 in efficiency of getting SDMs and DDMs. Based on LOD 〉 5.0, genetic distance _〈 40 cM between markers, 134 of 298 SDMs and DDMs from F1 population formed 55 linkage groups （LGs）, among which 39 LGs were included in eight homology groups（HGs）, 16 LGs were excluded, the map length reached 1 458.3 cM with an average distance of 10.9 cM between markers; 133 of 298 SDMs and DDMs from BC1 population made up 47 LGs, among which 34 LGs were composed in eight HGs except for 13 LGs, the map covered 1 059.6 cM with an average distance of 8.0 cM. At the same time, these SDMs and DDMs from Co419 and Y75/1/2 formed 34 LGs and 20 LGs, respectively, and these SDMs from two parents only made up 1 LGs; 19 LGs were obtained from these SDMs and DDMs of 02/356, and ROC25, 9 LGS were formed by SDMs from two parents; Co419〉Y75/1/2〉02/356=ROC2 according to forming number of LGs. These results indicated that F1 mapping population was better than BC1 mapping population in quality of constructing linkage map. The maps will provide the valuable information for locating gene, further research on genetic linkage map and MAS breeding.