Report on Phaseolus exploration in New Mexico, USA

Heat and drought are increasingly reducing bean production in most key areas worldwide. There is thus a justified need to increase variability in genebank collections for two species, P. acutifolius and P. filiformis, well known for tolerance to these stressors. The genebanks of USDA and CIAT currently hold less than five unique accessions of these two species from New Mexico, a state for which there are records since 1851. The compilation of these records in 100 Herbaria indicate 189 populations for six Phaseolus species. An 8-days exploration in four counties (Doña Ana, Grant, Hidalgo and Luna) of SW New Mexico yielded 14 populations, namely nine of P. acutifolius and one of P. filiformis. Nine populations of two species, P. acutifolius and P. grayanus, might be new additions to the flora of that state. Due to late and scarce rains (registered in late August-September 2023, instead of July-August in a regular year), most plants were found in seedling or early flowering-pod filling state which limited our ability to collect mature seed. We obtained soil microbe samples and herbarium specimens were made. Soil samples will be analyzed for all sites where herbarium specimens were obtained. The aberrant climate of the past summer shows the challenge these wild populations face towards drought and early frost patterns, and the capacity of potential survivors to such harsh conditions, which in turn are traits of high interest in bean breeding programs. Follow- up collections have resulted in the procurement of mature P. acutifolius seed from several sites.