Rice Blast Resistance Gene Pi1 Identified by MRG4766 Marker in 173 Yunnan Rice Landraces

Rice Blast is one of the most serious rice diseases and caused great yield losses every year in the world. It had been proved that using resistant rice varieties would be the most effective way to control this disease; therefore, mining the resistant genes might be important foundational work in the breeding program. In the present study, we identified the existence of the Pi1 gene among the tested 173 landraces collected from Yunnan Province by using the SSR marker MRG4766. The results showed that the Pi1 gene was found in 64 landraces, accounting for 36.99% in total of 173 landraces. 33 of 102 indica landraces (32.35%) and 31 of 71 japonica landraces (43.66%) both contained Pi1 gene. The landraces harboring the Pi1 gene were distributed in 29 counties of 11 prefectures in Yunnan province. The distribution frequency of Pi1 gene was higher in paddy-upland rice region in South margin of Yunnan (41.03%) than that of in single and or double indica cropping region in south of Yunnan (32.69%). The distribution frequency of Pi1 gene was 35.29% in single indica and or japonica cropping region in center of Yunnan, 35.29% in japonica cropping region in northeast of Yunnan and 33.33% in japonica cropping region in northwest highland of Yunnan.