小麦纹枯病抗性及抗性遗传的初步研究

 从一个多亲本的复式杂交后代中,选育了4个高抗纹枯病的小麦新品系,编号为MN-3、7、18和19。抗病性鉴定证明,在对照品种绵阳19病株率100%,发病等级4~5级的情况下,这4个新品系的病株率和发病等级分别在3.65%~6.98%和0~1之间。这4个品系与高感纹枯病的小麦品种绵阳19杂交,在F2代群体中植株符合抗:感=3:1的分离比率,在隐性亲本的测交后代中符合1:1的分离比率;在这4个品系之间的杂交后代群体中未观察到抗性的分离。试验结果指出,4个品系均含有同一个抗小麦纹枯病的单显性抗病基因,该基因被命名为Ses 1。本研究指出了小麦抗纹枯病育种的可能性,并为进一步研究小麦宿主和纹枯病菌原的相互关系及其遗传学提供了材料。

A PRELIMINARY STUDY ON RESISTANCE TO SHARP EYESPOT IN WHEAT ( Triticum aestivum L.)

Four wheat lines, which were named MN-3,-7,-18 and-19, and expressed high resistance to sharp eyespot, were selected from progeny of complex crosses. The rates of diseased plants and disease severity of these wheat lines ranged from 3.65% to 6.98% and from 0 to 1, respectively, whereas the control (cv. Mianyang 19) expressed 100% and 4-5, respectively. Analysis for resistance to sharp eyespot showed that the F2 populations of the crosses between these 4 lines and the susceptible cultivar (Mianyang 19) gave 3:1 ratios for resistant to susceptible plants. Segregation of resistance in populations resulted from backcrosses fit the 1:1 ratio. No segregation was found in the offsprings of crosses between these 4 lines. Results indicated that these wheat lines contained a single dominant gene for resistance to sharp eyespot. This gene was named Ses 1. The present study showed possibility to breed wheat resistant to sharp eyespot.