Yang Dabing, Tang Jianhao, Yang Di, Chen Ying, Ali Jauhar, Mou Tongmin
National Key Laboratory of Crop Genetic Improvement and National Centre of Plant Gene Research (Wuhan), Huazhong Agricultural University, Wuhan, China.
Rice Breeding Platform, International Rice Research Institute, DAPO Box 7777, Metro Manila, Philippines.
Rice (N Y). 2019 Sep 9;12(1):70. doi: 10.1186/s12284-019-0329-3.
Rice blast caused by Magnaporthe oryzae is one of the most widespread biotic constraints that threaten rice production. Using major resistance genes for rice blast resistance improvement is considered to be an efficient and technically feasible approach to achieve optimal grain yield.
We report here the introgression of the broad-spectrum blast resistance gene Pi2 into the genetic background of an elite PTGMS line, Feng39S, for enhancing it and its derived hybrid blast resistance through marker-assisted backcrossing (MABC) coupled with genomics-based background selection. Two PTGMS lines, designated as DB16206-34 and DB16206-38, stacking homozygous Pi2 were selected, and their genetic background had recurrent parent genome recovery of 99.67% detected by the SNP array RICE6K. DB16206-34 and DB16206-38 had high resistance frequency, with an average of 94.7%, when infected with 57 blast isolates over 2 years, and the resistance frequency of their derived hybrids ranged from 68.2% to 95.5% under inoculation of 22 blast isolates. The evaluation of results under natural blast epidemic field conditions showed that the selected PTGMS lines and their derived hybrids were resistant against leaf and neck blast. The characterizations of the critical temperature point of fertility-sterility alternation of the selected PTGMS lines, yield, main agronomic traits, and rice quality of the selected PTGMS lines and their hybrids were identical to those of the recurrent parent and its hybrids. DB16206-34/9311 or DB16206-38/9311 can be used as a blast-resistant version to replace the popular hybrid Fengliangyou 4. Likewise, DB16206-34/FXH No.1 or DB16206-38/FXH No.1 can also be used as a blast-resistant version to replace another popular hybrid Fengliangyou Xiang 1.
Our evaluation is the first successful case to apply MABC with genomics-based background selection to improve the blast resistance of PTGMS lines for two-line hybrid rice breeding.
由稻瘟病菌引起的稻瘟病是威胁水稻生产的最广泛的生物限制因素之一。利用主要抗性基因提高水稻对稻瘟病的抗性被认为是实现最佳谷物产量的一种有效且技术可行的方法。
我们在此报告通过标记辅助回交（MABC）结合基于基因组学的背景选择，将广谱抗稻瘟病基因Pi2导入优良光温敏核不育系丰39S的遗传背景中，以增强其及衍生杂交种的抗稻瘟病能力。筛选出两个携带纯合Pi2的光温敏核不育系，命名为DB16206 - 34和DB16206 - 38，通过SNP芯片RICE6K检测，其遗传背景中轮回亲本基因组的恢复率达99.67% . 在两年内用57个稻瘟病菌株进行接种时，DB16206 - 34和DB16206 - 38具有较高的抗性频率，平均为94.7%，在接种22个稻瘟病菌株的情况下，其衍生杂交种的抗性频率在68.2%至95.5%之间。在自然稻瘟病流行田间条件下的结果评估表明，筛选出的光温敏核不育系及其衍生杂交种对叶瘟和穗颈瘟具有抗性。筛选出的光温敏核不育系育性 - 不育性交替临界温度点、产量、主要农艺性状以及所选光温敏核不育系及其杂交种的稻米品质特征与轮回亲本及其杂交种相同。DB16206 - 34/9311或DB16206 - 38/9311可作为抗稻瘟病品种替代 popular hybrid Fengliangyou 4。同样，DB16206 - 34/FXH No.1或DB16206 - 38/FXH No.1也可作为抗稻瘟病品种替代另一个 popular hybrid Fengliangyou Xiang 1。
我们的评估是将MABC与基于基因组学的背景选择应用于改良两系杂交水稻光温敏核不育系稻瘟病抗性的首个成功案例。
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