Genetic Diversity Structure in Cultivated Alfalfa and Its Implications for Identifying Genes Linked to Agronomic Traits

Alfalfa, an allogamous autotetraploid forage legume, has seen renewed interest for sustainable agriculture. This research characterized genetic diversity in ten European varieties by measuring flowering date, plant habit, stem elongation rate, and maximum stem length over four years and by genotyping with eight SSR markers. High within‐variety diversity (expected heterozygosity of 0.75 for phenotypic traits and 0.80 for molecular markers) and clear phenotypic differentiation among varieties were observed. Sampling 40 genotypes per variety proved reliable for diversity analyses. Candidate‐gene association identified the Constans-like gene as a contributor to stem length differences, a key component of forage yield.