The Improvement And Application Of Backflow Induction And MAS Technology To Resistance Of Rice Brown Leatherhead

Brown planthopper is a typical sucking mouthpart pest,used to stay in the base of rice plant,spitting phloem juice,block ingphloem transport,resulting in growth arrest of rice,increasing of empty flat rate and causing the grain filled not well.Brown planthopper is one of the most important pest of rice production in China.Presently,our country insists on the prevention and control principle of "prevention first,comprehensive prevention and control" of the brown planthopper.The research of new genes and the development of new resitant rice varieties are considered to be the most cost-effective and environmentally-friendly control measures.In the study,Anti-Bph rice line B5(harboring Bph14 and Bph15)was used as the donor parent.Nanhui688,Two-line hybrid rice restorer line,was used as recipient parent.Hybridization and continuous backcrossing of NanHui688 and B5 were given to them in the research.During the process,SSR primer RM5665 and 15-6 were used to select gene Bph14,Bph15,respectively.57 lines were selected according to the inspecting of agronomic traits and the identification of brown planthopper in the seedling stage.The main research results are as follows:1.According to the gene type and the phenotype,we obtained 57 resistant lines,Among them,7 lineswere homozygous for Bph14 gene,11 lineswere homozygous for Bph15 gene,39 lines were homozygous for Bph14 and Bph15 genes.These lines can be used as an insect-resistant alternative to Nanhui 688.2.57 lines were tested for resistance to brown planthopper at seedling stage in the year of 2017.The Bph14 single-gene lines were all MR level with a mean of 4.4 points.The single-gene resistance of Bph15 was between MR-R with a mean of 3.6 points.The resistance of Bph14,15 double lines was between R-HR,with a mean value of1.3.Therefore,it can be concluded that the resistance of rice to Bph can be significantly increased by introducing the resistance gene.Based on the above resistance data,it can be concluded that: Bph14,15 double gene resistance> Bph15 single gene resistance> Bph14single-gene resistance.3.Identification result of 92 combinations showed that the resistant restorer lines could be used for combination with better resistance to Bph.In the meantime,when both the restorer line and the CMS line were combined,Combinations will be more resistant.4.Through this experiment,we screened 8 combinations with good insectresistance,high quality and high yield,which are SE21S/17RS42,LP631S/17RS-5,SE21S/17RS-13,SE21S/17RS-2,SE21S/17RS-47,LP631S/17RS-11,LP631S/17RS-20,LP631S/17RS-56,and we can further test for the accuracy of production.expecting to breeding good comprehensive properties.