Lucerne Dry Matter Accumulation Rate in Yield Differences

Lucerne (Medicago sativa L.) improvement historically has been directed at pest resistance, adaptation to climatic conditions and yield. Successful methods of detecting and increasing natural resistance to a range of insect and disease pests have been developed. Knowledge of what plant factors can be successfully manipulated to increase yield per se is less advanced. This research compared several lucernes differing in type and in date of release to determine if different rates of closed-canopy, forage dry matter accumulation have been a factor in yield increases, particularly between older and more recent material. Ten entries ranging in release date from 1857 to the present (one unreleased) and in dormancy class from 1 to 5 were seeded in 2 trials and sampled the first production year for forage accumulation. Three entries • Ladak (LOK), Maverick (MAV) and Vernal (VL) - showed a slightly higher rate of dry matter accumulation in the third growth of the season for both seedings, but there was no evidence that accumulation rate was associated with high or low final yield, that it had been increased in recent versus early releases, or that it related strictly to dormancy class. There was also no connection between release date and leaf proportion by weight or leaf area per unit forage weight.