Sources, Spectrum, Genetics, and Inheritance of Resistance Against pv. .

Common bean () is one of the most consumed agricultural products in the world. Its production is affected by common bacterial blight (CBB) caused by pv. and pv. . In this work, we investigated the spectrum, genetics, and inheritance of common bean resistance to pv. . Inoculation of nine selected cultivars with an pv. strain showed that BRS Radiante and IAPAR 16 were resistant. These two cultivars were also resistant to six pv. strains of different geographic origins, demonstrating their broad-spectrum resistances. BRS Radiante sustained smaller pv. populations than two susceptible cultivars. Stomatal densities of IAPAR 16 and BRS Radiante were significantly higher than or not different from susceptible cultivars. BRS Radiante showed the lowest general combining ability values and the combination BRS Radiante × Carioca MG the lowest specific combining ability (SCA) values, revealing the capacity of BRS Radiante to increase resistance to pv. . Positive and negative parental SCA values indicated dominant and recessive genes involved in pv. resistance. Resistance of the BRS Radiante × Carioca MG cross segregated in a 9:7 ratio in the F population, indicating that it is governed by two complementary dominant genes. Maximum likelihood analysis showed that the resistance of BRS Radiante to pv. is conferred by a gene of major effect with contribution of additional polygenes. This study contributes with important knowledge on the resistance against CBB in Brazilian common bean cultivars as well as with molecular tools for confirmation of common bean hybrids.