Resistance To Rice Stripe Disease In Rice Cultivar

In this study,resistance to rice stripe in major japonica rice cultivar of Jiangsu Province was identified.The resistant gene was located by SSR makers.The main results were summarized as follows:1.The mechanism of resistance to RSV and vector,SBPH was studied and analyzed in four rice varieties by using seedling inoculation,non-preference test and antibiosis test.The results indicated that the mechanism of resistance to RSV and vector SBPH was different.Huaiyoujing No.1 was moderately resistant to RSV but resistant to vector SBPH.Wuyujing No.3 was susceptible to RSV and vector SBPH. Yangjingjian7 was moderately resistant to RSV and SBPH.Zhendao88 was resistant to RSV,but moderately resistant to SBPH.IR24 was moderately resistant to RSV and SBPH2.Crosses were made between Zhendao88,Huaiyoujing No.1,Yangjingjian7 which were resistant to RSV and Wuyujing No.3 which was susceptible to RSV.The resistance to rice stripe virus was identified by the method of the seedling inoculation. Genetical analysis indicated that the resistance to rice stripe virus in Zhendao88,Huaiyoujing No.1,yangjingjian7 were controlled by a major gene,but were not influenced by cytoplasm.3.Reciprocal crosses were made among the four resistance cultivar:Zhendao88,Huaiyoujing No.1,yangjingjian7 and to analyze the allele inheritance model by the method of the seedling inoculation.The results indicated that the resistant gene in three cultivar were allelic.4.In this study,a resistance cultivar Zhendao88 was crossed to a susceptible cultivar Wuyujing No.3,A F₂ segregating population composed of 200 plants was constructed from the cross between Zhendao88 and Wuyujing No.3,and each F₂ plant was selfed to obtain F_2:3 line RSV resistance was evaluated using 200 F_2:3 lines by the method of the separation and the seedling inoculation,and the genotype of each F₂ plant was inferred from the phenotype of corresponding F_2:3 line.Genetic analysis indicated that the genetic model belongs to qualitative character inheritance and the resistance to rice stripe is controlled by a major gene.SSR assay and linkage analysis were carried out to detect the resistant gene.21 SSR primers located on 11 chromosome were screened.Amplified DNA fragments were separated with 8%denaturing PAGE(polyacrylamide gelelectrophoresis) and displayed by silver staining.Four polymorphic DNA fragment were found between Zhendao88 and Wuyujing No.3.The polymorphic index is 19.0%.The microsatellite locus RM229 was found to be linked to the resistance gene.The genetic distance between RM229 and the resistant gene is 4.7cM(centMorgan).The parent was detected with Random Amplified Polymorphic DNA.Product from PCR reaction were resolved by electrophoresis in 0.8%agarose.The positive ampliation of about 2500bp fragment generated from OPO11 was observed in Zhendao88.200 F₂ population was detected with RAPD maker OPO11.The result indicated that OPO11 was complete linkage to resistant gene.It proved that the resistant gene was stvb-i.5.In this study,a resistance cultivar Ning317 was crossed to a susceptible cultivar Wuyujing No.3,A F₂ segregating population composed of 200 plants was constructed from the cross between Ning317 and Wuyujing No.3,and each F₂ plant was selfed to obtain F_2:3 line RSV resistance was evaluated using 200 F_2:3 lines by the method of the separation and the seedling inoculation and the genotype of each F₂ plant was inferred from the phenotype of corresponding F_2:3 line.Genetic analysis indicated that the genetic model belongs to qualitative character inheritance and the resistance to rice stripe is controlled by a major gene.SSR assay and linkage analysis were carried out to detect the resistant gene.21 SSR primers located on 11 chromosome were screened.Six polymorphic DNA fragment were found between Ning317 and Wuyujing No.3.The polymorphic index is 28.6%.The microsatellite locus RM287 was found to be linked to the resistance gene.The genetic distance between RM287 and the resistant gene is 21.7cM(centMorgan).