The Genetic Mechanism Research Of Resistance To Magnaporthe Oryzae In The Super Early Rice Zhongzao 39

Rice blast is the most severe in the three major rice diseases. There is rice "cancer" said. Years of practical experience has shown that planting resistant varieties is the most cost-effective way to deal with rice blast. While, excavating and researching broad-spectrum resistance rice germplasm is the prerequisite for taking advantage of its durable resistance. Zhongzao 39, a rice breed with well resistance to rice blast was identified as the super rice by Ministry of Agriculture is widely grown in the south of Yangtze River, Jiangxi, Hunan, Hubei, Zhejiang and Anhui Province. It is a rare breeding resource resistance to rice blast breed in the early rice commercial varieties. In this study, in order to understand the resistance to rice blast in different rice regions in the north and south, 146 rice blast isolates taken from all 12 provinces were used to analysis the resistance spectrum of Zhongzao 39. Selecting the representative isolates to genetic analysis the resistance genes and QTL mapping of Zhongzao 39, and using 12 function markers of resistance genes to test Zhongzao 39 to clarify the genetic mechanism resistance to rice blast of Zhongzao 39. At the same time, find molecular markers that can be used to improve the resistance to rice blast of rice breeds that susceptible to rice blast or blast resistance degraded. The main findings are as follows:1. 146 strains taken from 12 provinces of the north and south were taken to divide physiological race. All the strains were divided into A, B, C, D, E, F, G 7 populations 40 physiological races. Group A and group C are the highest frequency of occurrence up to 23.3% and 24.0%, respectively. They are the dominant population. The total frequency Indica races appear to 59.6%, higher than the frequency of japonica races appeared 40.4%.2. 146 strains were used to resistance spectrum analysis Zhongzao 39; found that the total resistance spectrum of Zhongzao 39 is 78.8%, especially the resistance to indica races did well, reaching 82.8%. The average resistance spectrum of Zhongzao 39 in the South rice region was 83.2%. The resistance spectrum of Zhongzao 39 in Zhejiang Province, Guizhou Province, Guangxi Province is 92.9%, 93.1%, 100%, respectively, all reached 90%. Zhongzao 39 can serve as a good resistant resource to foster broad-spectrum resistant varieties in these areas.3. Selecting both representative and virulent physiological races 10-105(A49) and 12-157(B13) among 146 strains for the genetic analysis of resistance to Zhongzao 39. It was found that the resistance of Zhongzao 39 to strain 10-105(A49) was controlled by a dominant resistance gene. It was located at In Del molecular markers D622 and D638 on the chromosome 6, and the genetic distance was 2.8c M and 1.4c M. And it was co-segregated with the markers D627 and D629, tentatively named Pi-zc(t). The resistance of Zhongzao 39 to strain 12-157(B13) controlled by quantitative trait genes. Five QTLs q BR-6-1, q BR-6-2, q BR-6-3, q BR-6-4, q BR-6-5 were detected between In Del molecular markers D615 and D638 on chromosome 6.4. Using 12 functional markers that have been reported for the identification of resistance genes Piz, Piz-t, Pib, Pi9, Pid2, Pid3, Pi5, Pi36, Pi37, Pik, Pik-p, Pik-h to detect Zhongzao 39, Jiayu 66, Taizao 733, Zhongjiazao 17, and Zhongzu 1 hao. The results showed that seven resistance genes were detected in Zhongzao 39: Piz, Piz-t, Pid2, Pid3, Pi5, Pib, and Pi9. Wherein Piz, Piz-t, Pid2, Pid3, Pi9 5 resistance genes located In Del molecular markers D622 and D638 on chromosome 6. Resistance gene Pi5 was detected in Jiayu 66. Two resistance genes Pib and Pi5 were detected in Taizao 733. Pid2, Pid3, Pi5, Pib, Pi9 5 resistance genes were detected in Zhongjiazao 17. There was four resistance genes Pid2, Pid3, Pi5, Piz-t detected in Zhongzu 1 hao.5. Using Zhongzao 39 as donor parent, Jiayu 66, Taizao 733, Zhongjiazao 17, and Zhongzu 1 hao as recipient parents and recurrent parents to improve the resistance to rice blast of these 4 varieties. Taking advantage of functional makers and combining with the results of resistance identification and investigation of agronomic traits to select their backcross progeny BC1F5. We got 11 BC1F5 lines that the blast resistance and agronomic traits were all excellent: X127, X134, X83, X94, X105, X141, X143, X171, X77, X78 and X179.