小麦纹枯病抗性及抗性遗传的初步研究

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

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。

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.