Genetic Analysis of Rice False Smut Resistance Using Major Gene Plus Polygene Mixed Genetic Model

Abstract

Rice false smut, a fungus disease caused by Ustilaginoidea virens (Cooke) Takahashi, has become one of the most important rice diseases in China. It is of practical guiding significance to probe resistant mechanism for programming rice breeding for resistance to false smut. The present study was aimed to estimate the genetic model and genetic parameters of rice false smut resistance using the artificial inoculation technique to induce the rice false smut efficiently, and the disease rate index scored based on percentage of the infected grains. The experiment was conducted using 157 recombinant inbred lines (RILs) population of F10 derived from a cross of IR28 (indica) × Daguandao (japonica), two parents exhibited resistant and susceptible to rice false smut respectively. The results showed that the rice false smut resistance was controlled by two major genes plus polygene mixed genetic model (model E-1-3), and two major genes had equivalent additive effect of 11.41, their heritability was about 76.67%, while the heritability of polygene was about 22.86%. The resistance to rice false smut had significant major gene effect, and the results implied that not only major gene’s effect but also polygene’s effect should be considered in breeding for resistance to rice false smut.