The Study Of Transferring Rice Blast And Bacterial Blight Resistant Genes To Improve Restorer Lines Of Rice By Marker-assisted Selection

Rice is the crop which has been planting in the most area in our country and playing a decisive role in the national economy. As the plantation of hybrid rice increasing, rice blast and bacterial blight grow seriously and become two of the most serious diseases harming to rice production. Practice proofs that planting resistant rice variety is the most efficient way to resistant disease and marker-assisted selection (MAS) is one of the effective ways to improve the resistance to disease of hybrid rice.Pi-1and Pi-2are good rice blast resistance genes which both exist in the genome of rice variety WR1691and Xa-23is the bacterial blight resistance gene which owns the widest resistance spectrum and the strongest resistance and it exits in rice variety CBB23and Zhongye5112genomes. In this study, MAS was applied to transfer rice blast and bacterial blight resistance genes to restorer lines:Changhui891, ChanghuiT025and Changhui121which were owned the proprietary intellectual property rights by our laboratory, the main work were described as following:1. WF1691, CBB23and Zhongye5112were put to use as gene donors and the three restorer lines mentioned above were used as gene receptors. By hybridizing, backcrossing and MAS (SSR markers RM254, AP22and RM206which links to Pi-1, Pi-2and Xa-23genes separately were used), the three genes were oriented to the receptors. By once hybridization, three times of backcrossing and detection by molecular markers generation by generation, homozygous individuals (Changhui121modified offsprings were heterozygotic) were obtained at the BC3F2generation finally. Combining with economical traits,58and12individuals who were successfully transferred Pi-1, Pi-2and Xa-23genes were selected separately.2. Modified offsprings’blast and bacterial blight resistances were detected and the results revealed that the offsprings’resistances to these two diseases were highly improved.3.426SSR markers which spread at12chromosomes of rice were used to detect polymorphisms between the donor and receptor parents.97SSR markers were found polymorphic between WF1691and Changhui891with detectable rate22.8%. The number of SSR polymorphic markers between CBB23and Changhui891, ChanghuiT025is144and126separately which made the detectable rate33.8%and29.6%apiece.4. The SSR markers detected polymorphic were used in genetic background analysis and the results indicated that the reversion rates of improved plants which were imported genes Pi-1, Pi-2were98.94%and99.29%separately and the reversion rates of plants which were transferred Xa-23gene were94.37%and98.00%separately and the substantial reversion rates were higher than those of theoretical value.5. The agronomic traits such as Seed setting rate,1000-seed weight of modified offsprings were detected and the results showed that the traits had not notably changed. 6. Using primary receptors and modified offsprings to hybridize with male sterile lines RonfengA and WufengA to get hybrids. Agronomic traits of the F1hybrids were detected and the results showed that they were almost the same between different associations.