Genetic Study On Blast Resistance Of Rice Series Sterile Lines

Rice blast is one of the most devastating fungal diseases in rice region of world. To breed durable and broad-spectrum blast resistance of rice series sterile lines, and to reveal the genetic mechanism of resistance, it is hybrid rice breeding for disease resistance based on the theory and practice. This dissertation expatiated on the rice blast resistance breeding, the interaction between rice variety and Magnaporthe grisea and cloning and sequencing the RGA of plant. For breeding the male sterile lines resistance to rice blast during the 22 years as an examples. The study on the spectrum of this rice variety, interaction between rice variety and Magnaporthe grisea, rice blast resistence gene and homologous resistance gene analogues and revealed an male sterile line of rice blast resistance of inheritance, in order to use and clone of rice blast resistance gene effectively. Main research results are as follows:1.The use of indoor spraying seedling identification and blast strains then re-issued identification of areas of field-induced combination of natural methods for the 10 series male sterile line of rice and 6 restorer lines. According to the design of NCII, 2 generations genetic research materials including 16 parents(P), 60 hybrid rice varieties(F1 generations). We discuss its resistance spectrum using 20 strong blast strains which come from fields that susceptible to blast strains of FuJian province and 2 datas of serious blast areas of LongYan ChaDi country of FuJian province and EnShiZhou BaiGuo Country of Hubei Province. Fuyi A was cultivated in 1998. Xiafeng A, Gufeng A and Changfeng A were cultivated in 2001. Anfeng A, Quanfeng A, Changfeng A, Lefeng A, Fufeng A were cultivated in 2004. The results showed 9 sterile lines resistaance to blast fungus and 54 hybrid varieties represented high resistance to Fujian popular blast races and blast strain in ChaDi and Enshi, and resistance frequencies were 100%, have broad resistance spectrum. These varities not only contain the main effect dominant blast resistance gene, but also have a strong dominant genetic effect of blast resistance for the hybrid rice combinations. The average of resistance frequencies of 6 sterile resistance to blast fungus and 6 hybrid varities were 100%. Among 6 restoring lines, Shuhui 527 have broad resistance spectrum with resistance frequency of 72.3%. 5 restoring lines (Minghui 77, Wan 3, Fuhui 13, Minghui 86 Fuhui 5138) and Lianfeng A range have narrow resistance spectrum with resistance frequency of 4.5% to 13.6%.According to the results of blast resistance cluster analysis, we divided the 16 parents into two types. One type is blast resistance, including nine sterile lines of resistance to blast fungus(Fuyi A, Xiafeng A, Gufeng A, Changfeng A, Quanfeng A, Changfeng A, Lefeng A, Fufeng A, respectively.) and one sterile lines of moderate resistance, Shuhui 527. However, there were significant differences in resistance between Shuhui 527 and the other 9 sterile lines, while there were no significant differences in resistance between the other 9 sterile lines. The other type is susceptible to blast resistance, including one sterile lines of susceptible to blast fungus (LianfengA), and five restoring lines (Minghui 77, Wan 3, Fuhui 13, Minghui 86 Fuhui 5138).2. The 10 series male sterile line of rice for the female parent, 6 restorer lines of rice as male parent, similarly to the above-mentioned in the anti-spectrum analysis. According to the design of NCII, 3 generations genetic research materials including 16 parents(P), 60 F1 and 60 F2 were prepared. In order to reveal genetic mechanism of rice resistance to blast, genetic effect of interaction sterile line and blast fungus were analysised according to the interaction genetic model of additive-dominance-epistatic with the environment and statistical methods by 22 rice blast strains and in blast nursery nature achievement environment. The results showed the performance of blast resistance in rice were controlled by the blast resistance gene and environment interaction of the blast. The genetic control effects were followed in turn additive effect > interaction effect of dominant×blast stains > dominant effect > interaction effect of additive×blast stains > additive×additive epistatic effect. The interaction effect of additive×additive epistatic×blast stains was not existent. Blast resistance of 9 sterile lines (Xiafeng A, Changfeng A, Anfeng A, Fuyi A, Lefeng A, Changfeng A, Quanfeng A, Fufeng A, Gufeng A, respectively.) and Shuhui 527 can stably transmitted to offsprings, and can significantly improve blast resistance of offsprings. They have the very high breeding value in the anti-blast breeding. The heritability of additive genetic probability was 2.2 times of non-additive genetic probability in the tested rice varieties to blast resistance. The blast resistance causing from additive gene can stably transmitted to offsprings. The rice anti-blast ordinary narrow heritability was 6.4 times of the narrow mutual heritability. The results indicated it is effective for rice blast selection under environmental stress condition of the different rice blast strains.3. Male sterile line of rice resistance to blast in the pedigree, the selection of anti-agricultural source Gunong 13, TianguB, FuyiB, Gufeng B, Quanfung B for the whole material, in a set of recurrent parent CO39 for the six near-isogenic lines and a susceptible control Lijiangxintuanheigu (LTH) of the genetic background, the artificial group, respectively, with the Gumong 13, Tiangu B, Fuyi B, GufengB, QuanfengB and CO39-wide near-isogenic lines and a sense of disease control, including parental (P), F1, F2 3 generation of the genetic material to blast three strains spray indoor access to the seedling stage to identify bacteria. Using classical genetic analysis method, the maintainer line(Fuyi B, Gufeng B, Quanfeng B) of sterile line, the number and genetic mechanism of resistance gene to blast in resistance parents(Gunong 13, Tiangu B), and allelic relationship between known resistance gene to blast in near-isogenic lines(NILs) of CO39 were studied. The results indicated 5 parents have dominant resistance genes to blast. Gunong13, Fuyi B, Gufeng B and Quanfeng B contain 2 pairs of dominant resistance genes to blast, existing non-allelic relationship with Pi-1,Pi-2,Pi-3,Pi-4a,Pi-4b in NILs of CO39. Tiangu B contains 3 pairs of dominant resistance genes to blast, existing non-allelic relationship with Pi-1,Pi-2,Pi-4a,Pi-4b, while 1 pairs of dominant resistance genes existing allelic relationship with Pi-3.4. Based on conserved regions of the known NBS-LRR type R genes, a pair of degenerate primers PR2 and ER4 was designed. Using PCR method, the NBS-LRR type RGAs (resistance gene analogues) were isolated from 10 sterile lines( Fuyi A, Gufeng A etc.), 11 parents (Gunong13, V41B, etc.) and susceptible control LTH. The similarity and evolution relations of cloned RGAs were analysed. The reuslts indicated total 33 NBS-LRR type RGAs were obtained (2 RGAs from Gunong 13, Fuyi A, Digu B, Changfeng A, Xiafeng A, Lianfeng A, Lefeng A, V41B, Longtepu B, Bobai B, Jin 23B, respectively; 1 RGAs from Tiangu B, Gufeng A, Anfeng A, Quanfeng A, Changfeng A, Fufeng A, LTH, R931022, Y20, Y27 and Y12, respectively.). The deduced amino acids from 33 RGAs analysis showed 33 RGAs were divided into 12 classes by Clustal W and DNAstar. Further cluster analysis indicated 33 RGAs were divided into 9 classes by DNAsis software. Homology analysis showed sequence identity among the deduced amino acid sequences identity from 33 RGAs ranged from 19.8 % to 98.8%.