基于染色体片段导入系发掘抗玉米丝黑穗病主效QTL

Identification of Major QTL for Head Smut Resistance Based on Donor Chromosome Segment Introgression Line and Linkage Disequilibrium Analysis in Maize

选用抗玉米丝黑穗病自交系Mo17和SH15为供体,与受体感病自交系黄早四和昌7-2构建回交群体(BC3F1\BC4F2),通过田间人工接种玉米丝黑穗病原菌鉴定抗病性表现,评价群体抗病性。研究结果显示黄早四×(黄早四×Mo17)BC4F2群体发病率明显高于BC3F1群体;两个BC4F2黄早四×(黄早四×Mo17)和昌7-2×(昌7-2×SH15)群体的发病率差异较大。采用SSR标记分析抗病株的供体染色体导入片段,发现随着回交次数的增多,导入片段数量减少,但不同回交群体中供体导入片段数目明显不同。通过连锁不平衡分析,在染色体2.09和3.04区段发掘和验证2个抗玉米丝黑穗病主效QTL,连锁标记分别为umc2077和phio53或bnlg1965。本文研究结果为抗丝黑穗病基因精细定位和分子聚合育种提供了信息和材料。

Mo17 and SH15,two head smut resistant inbred lines as donor parents were chosen to produce BC3 F1 and BC4F2 populations of Huangzao4 × （ Huangzao4 × Mo17） and Chang7-2 × （ Chang7-2 × SH15 ） with two susceptible inbred lines Huangzao4 and ChangT-2 as recurrent parents,respectively. These populations were evaluated for head smut resistance with artificial inoculation under field condition. The disease incidence for BC4F2 populations of Huangzao4 ×（ Huangzao4 × Mo17） was higher than that of BC3 Fl population. The disease incidence was found different for the BC4 F： populations of Huangzao4 × （Huangzao4 × Mo17） and Chang7-2 × （ Chang7-2 × SH15 ）. The resistant individuals were genotyped by SSR markers on maize bins 2.09 and 3.04. The number of donor introgrssion segments in BC4F2 resistant plants was becoming less than that in BC3F1, and also varied between populations. Using linkage disequilibrium analysis, two major QTL for head smut resistance were identified, which are on bin 2.09 and bin 3.04,1inked with umc2077 and phio53 ／bnlg1965 ,respectively. The results obtained pro- vided both useful genetic information and materials for QTL mapping and marker assisted selection for head smut resistance in maize.