A candidate gene-marker approach to improve coldhardiness in alfalfa ( Medicago sativa )

摘要

In winter hardy alfalfa cultivars, cold acclimation occurs prior to the onset of freezing temperatures, and normally is accompanied with a series of genetic, metabolic and morphological adjustments. We investigated the association between three alleles derived from cold-regulated genes ( Msaic&V25 ) and the metabolic and morphological winter hardiness traits, in an F1 segregating population between the cross of M. sativa ssp. sativa (ABI408) and falcata (Wisfal-6). Transgressive segregation was observed in all traits. Broad sense heritability ranged from low for stem weight to high for shoot mass. The presence of allele a1 of Msaic B , a cold-regulated gene (COR), was positively associated with plant autumn height but negatively associated with root mass in the Wisfal-6 parent and not association to taproot metabolites content; it explained up to 11.4% of the winter hardiness variation in the segregating population. V25b1 , a COR gene, was associated to winter injury, explaining 7.8% of the phenotypic variation. Both RFLP probes can be used as markers for cold hardiness breeding scheme. Our results also suggest that winter injury and autumn biomass are controlled by different loci in this population.