Primary Mapping Main Resistance Locus Against Brown Planthopper In GXU184 Of Common Wild Rice (Oryza Rufipogon Griff.)

Nilaparvata lugens Stal(BPH)is one of the most serious pests of Oryza sativa L,which is famine and a typical sucking pest.Adults and nymphs are densely distributed at the bottom of rice plants,sucking the juice in the phloem at the stem and leaf and consuming their nutrients,leading to loss of water and dryness of the rice plants.In addition,the brown planthopper is still spreading grassy dwarf and tooth building disease,both main diseases transmitted by insects and seriously affecting the rice yield.At present,the main method for controlling the brown planthopper is chemical control.However,the continuous use of chemical insecticides does not only kill brown planthoppers,but also kills the predators of brown planthopper,pollutes the environment,destroys the ecological balance,is high economical cost,and even leads to the new emergence of chemical-resistance brown planthopper biotype which leads to the second occurrence of brown planthopper in even harmer degree.Exploiting new resistance genes and making them fully use are the most economical way to control the BPH.Combination of conventional breeding with molecular genetics and breeding would efficiently breed new varieties with broad spectrum resistance to the insect biotypes.Therefore,the present study is to exploit new BPH resistance genes and their molecular markers,so as to provide genetical guarantee for the BPH resistance breeding.High BPH reistant source GXU184 derived from conmon wild rice,Oryza rufipogo,n Griff.,was used in this study as research material to cross with rice cultivar 93 11 to construct F2 gene-mapping population.The BPH resistance characteristics and resistance level of GXU184 were analyzed by six parameters such as insec tresistance in seedling stage,insectresistance in seedling stage,insect resistance in adult stage,host selection of the insect,survival rate measurement,growth rate determination and honey dew value.The study results showed that GXU184 had better antibiosis and phobotaxis of resistance to the Nanning field mixture biotypes of the BPH.A number of 491pairs of SSR primers covering with rice whole genome were used tk to analyze the molecular polymorphism between the parents.15 each of resistant and susceptible extremes were selected to contruct resistant and susceptance gene pools and use to analysis with polymorphic SSR markers.8 markers,RM111,RM3,RM7193,M049,M052,M057,M058 and RM528 located together in chromosome 6 were found to correlative with the resistance.These relative markers were further used to analyze the resistant and susceptible individuals of the mapping population,and results confirmed the main effect resistance locus located in the same site between M057 and RM3.Results also showed that the efficience rate of markers M057 and RM3 used to check the F2 individuals and F3 lines reached more than 90%,indicating they have important value for marker-assisted selection in the BPH resistance breeding.