Andean common bean bulk breeding lines selected on multiple continents exhibit broad genetic diversity and stress adaptation

Abstract

AbstractThe low genetic diversity in Andean common bean (Phaseolus vulgaris) presents opportunities to improve stress tolerance and increase productivity. Thus, this study aimed to develop Andean bean breeding populations and evaluate them in suboptimal environments. Phaseolus Improvement Cooperative (PIC) populations were developed by crossing 53 Andean and five Middle American bean parents using bulk breeding. Selection and evaluation in Puerto Rico, South Africa, Tanzania, and Washington State resulted in 384 superior PIC lines used in subsequent studies. The PIC lines and the parents were genotyped using the common bean 12K single nucleotide polymorphism (SNP) chip, which yielded an initial set of 10,457 polymorphic SNPs. Population structure analyses using 2334 high‐quality SNPs indicated the strongest separation between heat tolerant landrace Indeterminate Jamacia Red (ADP‐0683)‐derived PIC lines and a group of lines derived from North American parents. The PIC lines and parents were grown under water stress in Puerto Rico in 2019 (n = 288) and 2020 (n = 176) to assess agronomic traits including seed yield. The best linear unbiased predictions for seed yield ranged from 31 to 388 kg ha−1 in 2019 and from 169 to 1762 kg ha−1 in 2020. Almost all the PIC lines matched or outperformed the parents in 2019, showing the utility of crossing lines from various origins. Genome‐wide association analysis identified SNPs associated with yield under drought stress at 44.2 Mb on Pv10, which could inform genetic studies for yield and drought tolerance. Overall, the PIC populations were useful for improving the genetic diversity and agronomic performance of Andean beans in suboptimal environments.