Genetic analysis of soybean resistance to Cercospora sojina Hara

Abstract

The genotypic variability of the resistance to Cercospora sojina can be used in breeding programs todevelop soybean resistant cultivars. The characterization of progenitors and the genetic system involved allowthe breeder to select the best progenitors, breeding method and selection procedure to be used. In this study adiallel of four soybean cultivars including the parents and all possible hybrids but the reciprocals were tested.Three resistant cultivars (Cristalina, Paraná and Uberaba) and a susceptible one (Bossier) and their F1 populationswere inoculated with the monosporic isolate identified as race 4. Results demonstrate that the resistance to C.sojina is controlled by a dominant gene or a gene-block; additive genetic effect and dominance are involved; thecontribution of the environmental variation is minimum; and the interaction among the genes ranges from thepartial to the complete dominance type, depending on the characteristic used in the evaluation of the resistance.