Gene pyramiding combinations confer resistance of Asian soybean rust

Abstract

Abstract Pyramiding Rpp genes is a promising strategy to achieve a more durable resistance against Asian soybean rust (ASR). The objective of this study was to develop Rpp ‐pyramided populations and evaluate their resistance and yield in field conditions. Fifteen pyramided populations carrying different combinations of Rpp genes were developed, and the F 3 lines were evaluated to phenotypic resistance and yield performance. Our results suggest that the Rpp1‐b of different resistant sources (PI 587880A, PI 594723, PI 4538A) have higher resistance and yield performance compared with other Rpp genes. Rpp ‐pyramided populations carrying two and three genes showed an increase in resistance compared with populations carrying a single Rpp gene. The best gene combinations were Rpp1‐b + Rpp5 , showing neither uredinia formation nor sporulation (immunity + RB1 phenotype reaction) in more than 70% of the F 3 population. Rpp ‐pyramided lines developed in this study have the potential to be used in backcross programs for improving ASR resistance.