Specific Loci in Genome of Wheat Milestone Parent Bima 4 and Their Transmission in Derivatives

Wheat (Triticum aestivum L.) cultivar Bima 4 is one of the most important milestone parents in China. The objectives of this study were to reveal the genetic structure of Bima 4 and the transmission of its specific loci in descendents using molecular markers. A total of 1239 simple sequence repeat (SSR), expressed sequence tag derived SSR (EST-SSR), and sequence tagged site (STS) markers covering the whole genome of wheat were screened with the 4 parents of the first generation of Bima 4 progenies, i.e., Bima 4, Early Piemium, Jubileina 2, and Ckopocneka JI-1. Thirty-three markers were effective to trace the specific loci of Bima 4 in the progenies. Seventy-six derivatives of Bima 4 were genotyped using these markers. Among them, 32 markers except for Xgwm577 could amplify the specific bands of Bima 4 in the first and the second generations derived from Bima 4. Eight and ten loci showed the transmission percentage larger than 50% in the first and the second generations, respectively. In the third and the fourth generations, 29 and 20 specific markers were observed. In these markers, 8 and 4 loci had the transmission rate higher than 50%, respectively. Among the specific loci, Xgwm261, Xedm80, SWES222, and CFE223 possessed inheritable frequency higher than 50% in all of the 4 generations. Furthermore, 18 loci of Bima 4 were detected in the progenies with genetic contribution ratio higher than 25%. This indicates that some desirable traits, such as yield, grain quality, disease resistance, and adaptability might be associated with these loci or the nearby chromosome regions in Bima 4, which were intensively selected in breeding programs. The important loci detected in this study provide information for understanding the genetic basis of Bima 4 as a milestone parent in wheat breeding.

摘 要为探讨小麦骨干亲本碧蚂4号的遗传构成及其特异位点在衍生后代中的传递特点, 利用覆盖小麦全基因组的1 239个SSR、EST-SSR和STS标记对碧蚂4号子一代衍生品种(系)的4个亲本进行标记筛选, 获得33个特异标记可用于76份碧蚂4号衍生材料的分析。在子一代和子二代材料中, 除标记Xgwm577外的32个标记均能扩增出碧蚂4号特异带, 且分别有8个和10个标记位点的传递频率大于50%; 在子三代和子四代材料中能扩增出碧蚂4号特异带的标记分别有29个和20个, 传递频率大于50%的标记位点分别有8个和4个; Xgwm261、Xedm80、SWES222和CFE223在4个世代中的传递频率都保持在50%以上; 有18个标记位点对衍生品种(系)的遗传贡献率大于25%; 推测这些基因组位点及其附近的染色体区域可能是被育种家强烈选择的部分, 碧蚂4号含有一些特殊的与重要农艺性状相关的基因组位点/区段, 可能是其成为骨干亲本的遗传基础。