Identification of a QTL for Plant Height in a New Dwarf Germplasm of Maize

Ai 2003 is a dwarf inbred line of maize (Zea mays L.) developed recently. To map the dwarfing gene in this inbred line, a segregation population containing 255 F2:3 families was constructed by crossing Ai 2003 to Ji 257 with normal plant height. A genetic linkage map was obtained using 114 simple sequence repeat (SSR) markers covering the entire maize genome. The total map length was 2852.1 cM with an average distance of 27.4 cM. Three QTLs were located on chromosomes 1 and 2, and they were highly identical in both Beijing and Hainan environments. The QTL located in the region of bin 1.10–1.11 explained 50.5% and 37.5% of plant height variation in Beijing and Hainan environment, respectively. This locus was further located in the 20–30 cM interval downstream of Dwarf plant8 (D8) gene, which is a well-known maize dwarfing gene.

摘 要用新发现的玉米矮生种质资源矮2003×冀257构建的255个F2:3家系为作图群体, 利用114个覆盖玉米全基因组的SSR标记构建连锁图谱, 图谱总长度2852.1 cM, 标记间平均距离为27.42 cM。2006年在北京与海南进行随机区组试验, 鉴定了255个F2:3家系成株期株高。用复合区间作图法(composite interval mapping, CIM), 对控制玉米株高性状的遗传位点进行QTL检测。在两个不同环境下均检测到相同的控制玉米株高的QTL位点3个, 分别位于第1和第2条染色体。其中在第1染色体上的1.10∼1.11区段存在一个控制株高的主效QTL, 与Dwarf plant8(D8)位置相近, 在北京和海南环境下分别能够解释株高表型变异的50.5%和37.5%, 作用方式表现为显性效应。序列分析结果显示, 该基因/QTL位于已知的D8基因下游20∼30 cM的染色体区间, 这可能是玉米中控制株高的一个新基因。