AUTHOR=Cruz Sergio , Lobatón Juan , Urban Milan O. , Ariza-Suarez Daniel , Raatz Bodo , Aparicio Johan , Mosquera Gloria , Beebe Stephen 

TITLE=Interspecific common bean population derived from Phaseolus acutifolius using a bridging genotype demonstrate useful adaptation to heat tolerance

JOURNAL=Frontiers in Plant Science

VOLUME=14

YEAR=2023

URL=https://www.frontiersin.org/journals/plant-science/articles/10.3389/fpls.2023.1145858

DOI=10.3389/fpls.2023.1145858

ISSN=1664-462X

ABSTRACT=<p>Common bean (<italic>Phaseolus vulgaris</italic> L.) is an important legume crop worldwide and is a major nutrient source in the tropics. Common bean reproductive development is strongly affected by heat stress, particularly overnight temperatures above 20°C. The desert Tepary bean (<italic>Phaseolus acutifolius</italic> A. Gray) offers a promising source of adaptative genes due to its natural acclimation to arid conditions. Hybridization between both species is challenging, requiring <italic>in vitro</italic> embryo rescue and multiple backcrossing cycles to restore fertility. This labor-intensive process constrains developing mapping populations necessary for studying heat tolerance. Here we show the development of an interspecific mapping population using a novel technique based on a bridging genotype derived from <italic>P. vulgaris</italic>, <italic>P. Acutifolius</italic> and <italic>P. parvifolius</italic> named VAP1 and is compatible with both common and tepary bean. The population was based on two wild <italic>P. acutifolius</italic> accessions, repeatedly crossed with Mesoamerican elite common bush bean breeding lines. The population was genotyped through genotyping-by-sequencing and evaluated for heat tolerance by genome-wide association studies. We found that the population harbored 59.8% introgressions from wild tepary, but also genetic regions from <italic>Phaseolus parvifolius</italic>, a relative represented in some early bridging crosses. We found 27 significative quantitative trait loci, nine located inside tepary introgressed segments exhibiting allelic effects that reduced seed weight, and increased the number of empty pods, seeds per pod, stem production and yield under high temperature conditions. Our results demonstrate that the bridging genotype VAP1 can intercross common bean with tepary bean and positively influence the physiology of derived interspecific lines, which displayed useful variance for heat tolerance.</p>