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Accelerated molecular breeding of a novel P/TGMS line with broad-spectrum resistance to rice blast and bacterial blight in two-line hybrid rice
- Mi, Jiaming, Yang, Dabing, Chen, Yi, Jiang, Jiefeng, Mou, Haipeng, Huang, Junbin, Ouyang, Yidan, Mou, Tongmin
- Rice 2018 v.11 no.1 pp. 11
- Oryza sativa, backcrossing, blast disease, blight, disease resistance, genes, grain yield, high-throughput nucleotide sequencing, hybrids, introgression, leaves, males, marker-assisted selection, rice, single nucleotide polymorphism, China
- BACKGROUND: Breeding two-line hybrid rice with disease resistance is an effective approach to stabilize rice yield in commercial rice production of China. RESULTS: We improved the blast and bacterial blight resistance of Guangzhan63-4S, an elite photoperiod- and thermo-sensitive male sterile (P/TGMS) line widely used in two-line hybrid rice, by introducing the R genes Pi2 and Xa7 conferring resistance to rice blast and bacterial blight, respectively. Through the backcrossing and gene pyramiding breeding coupled with molecular marker-assisted selection, a new P/TGMS line Hua1228S carrying Pi2, Xa7, and tms5 was developed. Based on 200,000 SNP markers by next-generation sequencing, Hua1228S covered 87.6% of the recurrent genome, as well as 4.5% of the donor genome from VE6219 and 7.9% from YR7029–39. When infected with seven tested Xanthomonas oryzae pv. oryzae strains, Hua1228S conferred high resistance (0 level) to six bacterial blight strains. Moreover, Hua1228S showed broad-spectrum resistance to rice blast isolates with a high resistance frequency of 90.91%. High levels of resistance to leaf blast and neck blast were observed under heavy disease pressure in natural field. Importantly, Hua1228S showed identical fertility-sterility alteration pattern to Guangzhan63-4S. Thus, two hybrid combinations Hua Liangyou 2821 and Hua Liangyou 284 derived from Hua1228S exhibited enhanced resistance and higher yield compared with the control variety Feng Liangyou 4. CONCLUSIONS: These results indicate that Hua1228S has tremendous potentiality to increase and stabilize the rice yield, through the introgression of two R genes by marker-assisted selection strategy.