Crop wild relatives of legumes: evolutionary resources for climate-responsive pre-breeding

Abstract

Legume crops are increasingly exposed to a combination of abiotic stresses - including drought, heat, salinity and flooding - alongside mounting biotic pressures from pathogens and insect pests. Historical domestication and modern breeding practices have substantially narrowed the genetic base of cultivated legumes, constraining their adaptive potential and limiting yield stability under fluctuating and extreme environments. Crop wild relatives (CWRs) represent a vital reservoir of genetic variation, providing alleles that enhance physiological resilience, reproductive stability, stress-responsive signaling and symbiotic nitrogen fixation. Across major and minor legumes such as chickpea, lentil, lupin, pea, soybean, cowpea and common bean, their CWRs harbor both single-trait and multifaceted adaptive mechanisms, including robust root systems, efficient water and nutrient use, early phenology and resistance to emerging pests and diseases. These wild gene pools maintain functional diversity lost during domestication and constitute essential evolutionary resources for sustaining legume productivity while buffering cropping systems against climate variability. Landraces complement CWRs by offering pre-adapted, locally optimized phenotypes, providing alleles suited to specific agro-ecological niches. The integration of CWRs and landraces into breeding pipelines allows the capture of both cryptic and novel alleles governing complex polygenic traits. Modern breeding innovations - including high-throughput phenotyping, multi-omics platforms, genomic selection and genome editing - have tremendously enhanced the ability to exploit this diversity systematically. By minimizing linkage drag and overcoming reproductive constraints, these technologies accelerate the development of climate-resilient cultivars. Harnessing the combined evolutionary potential of CWRs and landraces with contemporary breeding approaches enables legumes to achieve greater productivity, yield stability and nutritional quality under dynamic environmental conditions, thereby reinforcing their role in sustainable agriculture and global food security.