基于MAS的小麦抗赤霉病育种材料抗性评价

为了提高黄淮海麦区小麦育种材料的赤霉病抗性,采用分子标记辅助选择的方法,将来自望水白的4个抗赤霉病主效QTL 3B-QTL、4B-QTL、5A-QTL和6B-QTL导入不同的感病背景中,在后代BC1F3和BC1F4株系中评价它们的抗病效应和农艺性状回复情况。结果表明:(1)导入4个抗病QTL株系的平均病小穗率和病粒率分别为12.2%和6.3%,而受体亲本则分别达到59.1%和44.2%,抗病性显著提高;(2)病小穗数和病粒率与穗长及株高极显著负相关,但与可育小穗数、百粒重、旗叶长和旗叶宽等农艺性状指标没有显著相关性。因此,通过导入抗病主效QTL可以显著改善感病材料的抗性,为进一步选育高产抗病品种提供基础材料。不良农艺性状的紧密连锁阻碍着抗赤霉病主效QTL的高效利用,需要通过继续回交或与其他品种杂交来打破这种遗传连锁关系。

Comprehensive evaluation of breeding materials for resistance to wheat scab based on MAS

Based on molecular marker-assisted selection, four major QTL genes derived from Wangshuibai chromosome 3B, 6B, 4B, and 5A resistant to wheat scab were transferred into six different susceptible genetic backgrounds to improve wheat disease-tolerance in the Huang-huai-hai area, their resistance and agronomic traits were evaluated subsequently at BC1F3 and BC1F4 progeny lines. Results obtained from field trail for two consecutive years showed that the average percentage of diseased spikelet and fuasrium diseased kernel of the lines carried four QTLs was 12.2% and 6.3% while those of the susceptible recipient parents up to 59.1% and 44.2%, respectively, indicating the wheat lines performed more significantly than their recipient parents in the disease tolerance, and that the plant height and spike length showed apparently negative correlation with percentage of diseased spikelet and fuasrium diseased kernel, but there was not significant difference between lines and recipient parents in flag leaf width, fertile spikelet number, grain number and hundred grain weight. The resistance to wheat scab would be enhanced after pyramiding major QTLs in susceptible germplasm, therefore, the lines with four QTLs could be applied further in wheat breeding , but further backcrossing or cross with other varieties could be helpful in breaking the close linkage of major QTLs to the adverse agronomic traits.