The lima bean breeding decreases the ability of segregating generations to nodulate with indigenous rhizobia

Abstract

It is well-known that plant breeding aims to develop new plant varieties with desirable traits. However, this process promotes the loss of certain genetic traits, such as nodulation by indigenous rhizobia in soils. Therefore, this study aimed to assess the potential effect of lima bean breeding on root nodulation by indigenous rhizobia. Five genotypes were utilized in this experiment, following the steps of lima bean breeding, including two parent plants (P1 and P2) and three segregating generations (F2, F7, and F8). The plant growth and nodulation traits were evaluated during the flowering period, which varied depending on each genotype. The results of the multivariate analysis clearly separated the parent plants from the segregating generations based on nodulation traits. Nodulation by indigenous rhizobia varied across the evaluated genotypes and generally decreased as the generations advanced. The highest nodulation traits were found in P1 and P2, while they decreased in F2 and were undetectable in F7 and F8, indicating a loss of ability to nodulate in this region with the advancement of generations. This study demonstrated that lima bean breeding has a negative impact on the ability of indigenous rhizobia to nodulate lima bean genotypes during the advance generations.