小麦白粉病抗性基因的聚合及其分子标记辅助选择

Pyramiding and Marker-assisted Selection for Powdery Mildew Resistance Genes in Common Wheat

采用了在早代进行抗性鉴定、淘汰感病株、保留抗病株继续种植、较晚世代（Ｆ４代）进行抗性鉴定结合分子标记辅助选择的策略，提高了选到聚合抗性植株的效率。利用与Ｐｍ２、Ｐｍ４ａ、Ｐｍ８、Ｐｍ２１紧密连锁或共分离的ＲＦＬＰ标记和ＰＣＲ标记（ＳＣＡＲ标记），对含有这些基因的优良品系间配制的杂交组合的Ｆ４代进行了分子标记辅助育种选择，并结合抗性鉴定，筛选到 １４株 Ｐｍ４ａ ＋ Ｐｍ２１的植株， １６株 Ｐｍ２＋ Ｐｍ４ａ的植株，６株Ｐｍ８＋Ｐｍ２１的植株。应该引起注意的是，Ｐｍ２＋ Ｐｍ４ａ对混合白粉病菌的抗性达到高抗至免疫水平，而 Ｐｍ２和 Ｐｍ４ａ单独存在时则抗性较差，表明聚合抗病基因植株的抗性提高了，为培育具有持久抗性的品系或品种提供了新思路，它在实践和理论研究上都将具有重要意义。

This project used the strategy of discarding susceptible individual Plants and keeping resistance ones by resistance identification in breeding populations and Planted resistant plants next in earlier generations (F1 - F3), and performing marker-assisted selection combining resistance identification in later generation (F4 generation) for pyramiding powdery mildew resistance. F4 populations from crosses of elite parents possessing different Pm genes were screened by using molecular markers tightly linked to Pm2, Pm4a, Pm8 and Pm21 genes, respectively. Fourteen individual plants with Pm4a and Pm21 out of 40 F4 Plants were identified. Sixteen individual plants containing Pm2 and Pm4a out of 80 F4 plants and six plants possessing Pm8 + Pm21 out of 58 F2 plants were screened. Notably, the plants with Pm2 and Pm4a showed high level resistance or immunity to powdery mildew, while plants with single Pm2 or Pm4a had lower resistance. The results suggest that the strategy of pyramiding different Pm genes provide an alternative way of utilizing resistance gene resources for breeding new types of resistance lines and cultivars, which will have significance not only in breeding practice but also in theoretical research.