MAS育种改良籼稻恢复系R747及其杂交种稻瘟病抗性

Improvement of Blast Resistance of Indica Rice Restorer Line R747 and Its Hybrid by MAS Technology

为了改良籼稻恢复系R747及其杂交种的稻瘟病抗性,以携带广谱抗稻瘟病基因Pi9的籼稻品系75-1-127为供体亲本,以R747为受体及轮回亲本,利用Pi9基因内功能标记,开展分子标记辅助选择育种实践。获得了如下主要结果:室内接种试验表明,75-1-127与R747对来自国内外不同稻区的24份稻瘟菌菌株的抗菌谱差异显著,抗性频率分别为91.7%和41.7%,两亲本在田间自然病圃苗瘟抗性表现分别为高抗和高感;根据Pi9基因序列信息开发了一个共显性多态标记SPL-1,该标记在75-1-127和R747基因组中分别扩增出一条745 bp和一条850 bp的条带,标记基因型对稻瘟病抗感表型的选择效率为100%;从BC6F3株系中遴选出一个高抗苗瘟的改良恢复系R747-Pi9,并用它与不育系培矮64S、P88S和桃1A分别配制出高抗稻瘟病的杂交种;利用分布于水稻全基因组不同位点的220个SSR标记,分析了改良抗病恢复系R747-Pi9与受体亲本R747的遗传背景差异,结果表明R747-Pi9对R747的背景回复率为0.94。本研究通过分子标记辅助选择和连续回交育种,成功定向改良了恢复系R747及其杂交种的稻瘟病抗性。

To improve blast resistance of the indica rest orer line R747 and its hybrids, the indica rice line75-1-127 carrying a broad spectrum rice blast resistance gene Pi9 was used as the donor parent and R747 as the recipient and recurrent parent. Functional markers of Pi9 gene were used to carry out molecular marker-assisted selection breeding. The main results obtained were as follows: Greenhouse inoculation showed that resistance spectra to 24 tested worldwide M. oryzae isolates were obviously different between 75-1-127 and R747, with resistance frequencies of 91.7% and 41.7% respectively. Moreover, two parents showed high resistance and high susceptibility to blast in natural field nursery, respectively. Based on the sequence information of Pi9 gene, a co-dominant polymorphic marker SPL-1 was developed. A 745 bp band was amplified from 75-1-127 genome while a 850 bp band from R747, and the selection efficiency by SPL-1 genotype for blast resistance phenotype reached 100%. A seedling blast resistance improved restorer ’R747-Pi9’ was bred from the BC6 F3 strains, and hybrids developed by R747-Pi9 and three rice sterile lines Peiai64 S, P88 S and Tao1 A also showed high-level blast resistance in field nursery. Using 220 SSR markers distributed in different rice genome locations, the genetic background differences between the improved blast resistant restorer line R747-Pi9 and the recipient parent R747 were analyzed, and the results indicated that the background response rate of R747-Pi9 to R747 was 0.94. In this study, the rice blast resistance of the indica restorer R747 and its hybrids was successfully improved through molecular marker-assisted selection and continuous backcross breeding.