Advances in basic biology of alfalfa (Medicago sativa L.): a comprehensive overview

Abstract

Alfalfa (Medicago sativa L.), a perennial legume forage, has been broadly cultivated owing to a variety of favorable characteristics, including comprehensive ecological adaptability, superior nutritive value and palatability, and nitrogen fixation capacity. The productivity traits of alfalfa, specifically its biomass yield and forage quality, are significantly influenced by a series of determinants, including internal developmental factors and external environmental cues. However, the regulatory mechanisms underlying the fundamental biological problems of alfalfa remain elusive. Here, we conducted a comprehensive review focusing on the genomics of alfalfa, advancements in gene-editing technologies, and the identification of genes that control pivotal agronomic characteristics, including biomass formation, nutritional quality, flowering time, and resistance to various stresses. Moreover, a molecular design roadmap for the 'ideal alfalfa' has been proposed and the potential of pangenomes, self-incompatibility mechanisms, de novo domestication, and intelligent breeding strategies to enhance alfalfa's yield, quality, and resilience were further discussed. This review will provide comprehensive information on the basic biology of alfalfa and offer new insights for the cultivation of ideal alfalfa.

Figure 1

Alfalfa development stages. The growth and development stages of alfalfa include: seed germination, sprouting, seedling (or resprouting) stage, branching stage, budding stage, mowing, and postmowing regrowth stage.

Figure 2

Agronomic traits and distinctive characteristics affecting the yield and quality of alfalfa.

Figure 3

The gene regulatory network for critical agronomic traits in alfalfa.

Figure 4

Molecular design roadmap for ‘ideal alfalfa’.