Genome-wide genotyping data renew knowledge on genetic diversity of a worldwide alfalfa collection and give insights on genetic control of phenology traits

The dataset is composed with 400 cultivated accessions (378 cultivars and 22 landraces) whose fall (autumn) dormancy was mainly between 3 and 7 on a 1-11 scale. Their origin, based on the place they have been collected (landraces) or initially selected and registered (cultivars) was Europe (318 accessions), North America (45 accessions), South America (16 accessions), China (17 accessions), Middle East (3 accessions) and Japan (1 accession). In addition, 617 accessions representing advanced breeding material obtained by five European breeders were included. All the 1017 accessions were genotyped and used for genetic structure study while only the 400 ‘cultivated accessions’ were phenotyped for phenology and used for GWAS and GS studies. All accessions have been coded by a unique identifier (EUCLEG_ID) with the format: EUC_MS_xxxx, EUC referring to the EU project EUCLEG (H2020, N°737212, 2017-2021), MS to Medicago sativa, and xxx a number from 001 to 1017.