Polyploidy and Mutagenic Germplasm Innovation in Minor Legumes: Paradigm Shift and Challenges from Model Crops to...

Minor legume crops, including mung bean (Vigna radiata), cowpea, and adzuki bean, are crucial for global food security and sustainable agriculture, yet their genetic improvement has been hindered by narrow germplasm resources and lagging breeding technologies. This article systematically reviews the strategy of integrating polyploid breeding with mutagenic breeding as an innovative pathway to overcome the genetic bottlenecks of minor legumes. It focuses on insights gained from model plants and major legume crops like soybean and alfalfa regarding polyploid advantages and efficient mutagenesis techniques. Furthermore, it provides an in-depth analysis of the unique challenges and adaptation barriers encountered when transferring these paradigms to minor crops. Using mung bean as a representative case study, this review highlights specific challenges, including the creation of stable polyploid germplasm, the elucidation of complex regulatory mechanisms in polyploid genomes, and the technical bottlenecks in gene mapping and functional validation. The review also outlines future directions involving the integration of cutting-edge technologies-such as multi-omics, high-throughput phenomics, and gene editing-to establish a holistic research framework of "germplasm innovation-gene mapping-designer breeding". This integrated approach aims to advance the breeding practices of minor legumes into a new era of precision design.