Agronomic Characters Evaluation And Preliminary Genetic Analysis Of 27 Resistant Rice Germplasm Resources To Rice False Smut (Ustilaginoidea Virens)

Rice false smut, caused by Ustilaginoidea virens (Cooke) Takahashi, is one of the most devastating disease of rice worldwide. Development and deployment resistant cultivars is the most practical and cost-efficient method for controlling of this disease. Study and utilization resistance of germplasm resources is the basis for resistance breeding. In this study, resistance to rice false smut and agronomic characters of the 27 rice germplasm resources were detected, and the restoring and maintaining characteristics of the 27 varieties were evaluated. The susceptible variety 08R2394 was crossed with 11 resistant resources (MR183-2,Luyou3,RP2263-2556-2,IRAT144,Shangkang7704,IRBN95-268,R6,92-548,R19,R23 and IR28153), and back-cross were made, then the degree of dominance of the resistant genes of F1 and rF1 were tested. Furthermore, the resistance of F2 population from 08R2394/MR183-2, 08R2394/IR-92-548,08R2394/CNA8502,08R2394/IR99-49,08R2394/IR13149-19-1,08R2394/IR28153 were detected respectively, then calculated the number of genes that controled the resistances.1) The result suggested that disease spike rate of 7 cultivars were 0.00,17 varieties were resistant to rice false smut in three years. So those resistant resources were invaluable for breeding, and shoud be used widely in Sichuan province.2) The 27 rice germplasm resources were clustered into 2 groups based on agronomic characters:GroupⅠwas smaller spike but tillering more; GroupⅡwas with bigger panicle but tillering less.3) Six rice germplasm resources from the 27 varieties were restoring ability to infertile line F3A; 13 germplasm resources had maintaining ability to infertile line; 7 resources had both function.4) The identification of the dominant degree of F1 population from cross 11 resistant varieties and susceptible cultivar 08R2394, indicated that only the resistance from MR183-2 followed recessive inheritance in F1 population, remaining 9 resistant resources were controled by dominant genes and Luyou-313 was unknown.5) On the bases of the secend standard of per plant resistance identification, the phenotype characters of F2 population from 08R2394/92-548 and 08R2394/IR28153 showed that the resistance from 92-548 and IR28153 were controled by one and two genes respectively.