Phytophthora resistance behavior of soybean F1 populations with pyramided Rps genes

Abstract The objective of this work was to identify the resistance behavior of soybean (Glycine max) F1 populations with pyramided Rps genes, when subjected to inoculation with pathotypes of Phytophthora sojae. In 2020 and 2021, hybridizations were performed considering the presence of Rps genes from different loci in the parents. To characterize the F1 generation, pathotypes PS2.4, PS14.4, PS34.1, PS36.1, and CMES1608 were inoculated into the lateral branches of adult plants. The reaction to the pathotypes was evaluated in a greenhouse experiment, through the percentage of infected, dead, and healthy lateral branches. The study allowed identifying the virulent reaction of parents and their inoculated progenies. Progenies from virulent combinations of the same pathotype did not present new resistances. Resistance is increased by the complementarity of different Rps genes from the genotypes used to obtain the F1 progenies. Soybean F1 populations with pyramided Rps genes are an efficient genetic tool to help control Phytophthora sojae.