利用分子标记辅助选择技术改良水稻恢复系N175的稻瘟病抗性

以水稻恢复系N175为轮回亲本,与携有稻瘟病抗病基因Pi-1/Pi-9/Pi-kh的恢复系金恢1059进行杂交和3次回交,并利用SSR标记对抗病基因进行跟踪选择,最终得到了16个N175的抗病近等基因系,其遗传背景恢复比例均达96.50%以上。室内接菌和田间自然诱发鉴定表明,N175的抗病近等基因系及其与不育系龙特浦A组配的杂交种的抗性表现均为抗(R),与供体亲本金恢1059相当,而N175和杂种特优175(龙特浦A/N175)分别表现为感(S)和高感(HS)。多数近等基因系与龙特浦A配制的杂种的主要农艺性状与特优175相近,其中8个杂种单株粒重高于特优175,2个杂种比特优175增产10%以上,说明这些新育成的抗病杂种基本上保留了特优175的优良特点,个别杂种的综合性状还明显优于特优175。

Improvement of rice blast resistance of restorer line N175 by marker-assisted selection

With restorer lines Jinhui 1059 carrying rice blast resistant genes Pi-Kh , Pi-1 and Pi-9 as donor parent and N175 as re-cipient parent, a cross between the two parents was conducted, followed by three rounds of backcrossing. Marker-assisted selection was performed during the process, by which the three target resistant genes were successfully pyramided into N175, resulting in 16 near-isogenic lines ( NILs) , each with more than 96.50% similarity to N175 in genetic background. The results of blast resistance test in greenhouse and field indicated that the 16 NILs and their hybrids with male sterile line Longtepu A all exhibited a high resist-ance level equivalent to the donor parent Jinhui 1059, much higher than the recipient parent N175 and its hybrid with Longtepu A, Teyou 175, respectively. Most of the hybrids of the NILs with Longtepu A were very similar to Teyou 175 in main agronomic traits. Among the hybrids, 8 showed higher grain weight per plant than Teyou 175, and 2 showed over 10% increase in yield. The results suggest that the newly bred blast-resistant hybrids basically maintain the elite comprehensive agronomic traits of Teyou 175, with some obviously superior to Teyou 175.