Interspecific common bean population derived from

Area of Science:

• Plant genetics
• Crop science
• Agriculture

Background:

• Common bean (Phaseolus vulgaris L.) is a vital global legume crop, but its reproductive development is sensitive to heat stress, especially elevated nighttime temperatures.
• Desert Tepary bean (Phaseolus acutifolius A. Gray) possesses valuable genes for heat and drought adaptation due to its natural acclimation to arid environments.
• Conventional hybridization between common bean and tepary bean is difficult, requiring complex techniques like in vitro embryo rescue and extensive backcrossing, hindering the development of essential mapping populations for heat tolerance research.

Purpose of the Study:

• To develop a novel interspecific mapping population for studying heat tolerance in common beans.
• To overcome the challenges associated with hybridizing common bean and tepary bean species.
• To identify genetic regions conferring heat tolerance by utilizing a unique bridging genotype.

Main Methods:

• Development of a bridging genotype (VAP1) from Phaseolus vulgaris, P. acutifolius, and P. parvifolius, compatible with both common and tepary beans.
• Creation of an interspecific mapping population through repeated crosses between wild P. acutifolius accessions and Mesoamerican elite common bush bean lines.
• Genotyping-by-sequencing (GBS) for population genotyping and genome-wide association studies (GWAS) for heat tolerance evaluation.

Main Results:

• The developed mapping population contained significant introgressions (59.8%) from wild tepary bean and genetic regions from P. parvifolius.
• Twenty-seven significant quantitative trait loci (QTLs) were identified, with nine located within tepary introgressed segments.
• These introgressed segments influenced traits such as seed weight, pod set, seed number, stem production, and yield under high-temperature conditions.

Conclusions:

• The bridging genotype VAP1 effectively facilitates interspecific crosses between common bean and tepary bean.
• The derived interspecific lines exhibit beneficial physiological variations for heat tolerance.
• This novel mapping population provides a valuable resource for dissecting the genetic basis of heat tolerance in common beans and for breeding climate-resilient varieties.