Genetic Analysis Of Resistance To Brown Planthopper Of Two Rice Varieties And Fine Mapping Of Bph36(t)

Brown planthopper(Nilaparvata lugens Stal)is the most serious pest of rice.The brown planthopper can also be used as a virus vector to transmit rice leaf dwarf disease.For a long time,people mainly used chemical control to control brown planthopper,and the use of chemical pesticides and fertilizers not only consumes a lot of manpower and resources,but also pollutes the environment and increases the resistance of brown planthopper.Using host resistance is the most effective method to control brown planthopper.Therefore,it is necessary to screen the resistance sources and find new resistance genes to cultivate brown planthopper resistant rice varieties.Therefore,this study constructed genetic population with two brown planthopper resistant rice resources and susceptible rice varieties screened in the previous stage,carried out genetic analysis on the resistance of brown planthopper,and identified and located new brown planthopper resistant genes,laying a foundation for the cloning of brown planthopper resistant genes and the cultivation of brown planthopper resistant varieties.The main research results are as follows:Genetic analysis of resistance to brown planthopper of PSL2 and fine mapping of Bph36(t)1.Standard seedbox screening test was used to identify the resistance of brown planthopper PSL2 and 02428.The results showed that the resistance levels of PSL and 02428 were 1 and 9,indicating that PSL2 had high resistance to brown planthopper and 02428 had high sensitivity..PSL2 and 02428 were used to construct F2:3 population,and 112 F2:3 families of brown planthopper were identified.The resistance of 112 families of brown planthopper was continuously distributed,and the resistance of brown planthopper with phenotype PSL2 may be controlled by multiple genes.2.A preliminary mapping of brown planthopper genes was conducted on 12 individual plants with insect of resistance and insect of susceptibility,and the signs of chain were found on chromosome 6 of 25 pairs of markers with good polymorphism between parents were used to construct the sixth chromosome mapping of rice,and QTL analysis was conducted in combination with phenotypic data.QTL was detected between RM190 and PSL-7 with LOD of 7.2 and contribution rate of 25%.3.In order to complete the fine mapping of this gene,BC1F2 and BC1F3 populations with 02428 and R527 as backcross parents were constructed,markers on both sides of the preliminary mapping were used to get the recombinant individuals,and a total of 70 exchange strains were getted.By using the above recombinant individuals,the gene was finally fine mapped within a physical distance of 50 kb.There are eight ORFs predicated in this region.Sequencing revealed that only two ORFs differed in sequence.Among them,ORF1 encodes a CaLB domain containing protein;ORF2 encodes an SDR family protein.Sequencing revealed that ORF1 had single replacement and deletion between in both resistant and susceptible parent differences in the promoter region of this gene.ORF2 had three amino acid substitutions in exons and seveal single replacement in the promoter region.Fine mapping of Bph36(t)can establish the foundation of its map-base clonning as well as the utilization in molecular breeding.Genetic analysis and gene molecular mapping of BARI SUTAP against brown planthopper1.A Indian landrac BARI SUTAP with high resistance to brown planthopper was selected local cultivars coming from Southeast Asia and South Asia.In this study,the resistance of BARI SUTAP and 02428 brown planthopper were identified by standard seedbox screening test,and the resistance levels of BARI SUTAP and 02428 were 1 and 9,respectively.BARI SUTAP was highly resistant to brown planthoppers,while 02428 was highly sensitive.Furthermore,BARI SUTAP and 02428 were used to construct an F2:3 population with 400 families,and 95 F2:3 families were identified for resistance of brown planthopper.The resistance of brown planthopper in 95 families was continuously distributed,and the resistance of this species may be controlled by multiple genes.2.125 pairs of markers with good polymorphism in both parents were screened from 900 pairs of KASP markers in the whole rice genome,and the molecular map of BARI SUTAP and F2 population 02428 was constructed,and the QTL was detected by brown planthopper phenotype data of 95 families.We detected a quantitative trait loci(QTL)of BPH resistance on chromosomes 1,and LOD was detected in chromosome 1,which accounted for 15.48%of the phenotypic variance.The discovery and mapping of the new anti-brown planthopper genes establish a foundation for the cloning and functional analysis of genes and the breeding of new rice varieties with marker—assisted selection.