| Annual medics have potential as a short-season annual crop to supply forage when traditional supplies are inadequate and as a model crop for studying the genetics of legumes. Assessing growth variation among M. truncatula under autumn conditions is an important first step for improving M. truncatula yield and identifying potential as a winter annual forage. Our objective was to identify the variation in dry matter accumulation in roots and shoots of M. truncatula accessions under simulated autumn (SAC) and constant growth conditions (CGC). Thirty-five M. truncatula accessions chosen for high biomass and winter vigor from various areas of collection/origin, and five fall dormancy checks of alfalfa were used for this study. Seeds were planted in the greenhouse and four weeks later seedlings were transferred to growth chambers under SAC and CGC growth conditions. Root dry weight and shoot dry weight were recorded after the treatment period. The time to first flower of the genotypes was also recorded. Genotypes differed for dry weights and first flowering. Root and shoot dry weights of the accessions were higher under modulated autumn conditions than under constant growth temperature. Accessions grown at constant temperature (25°C) flowered earlier compared to simulated fall conditions. The geographic origin of the accessions used in this study did not appear to indicate growth traits but to time first flower, in some instances. The results revealed the presence of exploitable yield variation among M. truncatula accessions. M. truncatula has potential as annual forage for harvest in fall. The differential growth performances observed in some of the accessions may also provide interesting materials for future genetic studies. |
