Advances and Challenges in Haploid Induction for Warm-Season Legumes

Haploid induction via doubled haploid (DH) technology is pivotal for achieving true homozygosity in plant breeding; however, Fabaceae species lag in establishing effective haploidization methods. This review explores recent advances in DH techniques for warm-season legumes, including soybean, cowpea, pigeon pea, common bean, peanut, mung bean, and winged bean, highlighting key challenges and perspectives. While anther culture, cold pretreatment, and MS-based medium with growth regulators demonstrate potential, fully reproducible protocols remain elusive. Advances in microspore-derived embryogenesis have improved regeneration consistency in soybeans, cowpeas, and peanuts. Key areas for improving DH technology include optimizing regeneration conditions, such as shortening the callus phase and accelerating embryo and shoot development. Recent advancements in CRISPR/Cas9-mediated genome modifications, targeting genes like CENH3, MTL, and DMP, offer promising strategies to enhance efficiency and overcome resistance to conventional methods. Integrating molecular tools with haploid induction and conventional breeding techniques can significantly improve legume breeding and productivity.