Influence of seed quality on field establishment and forage yield of white clover (Trifolium repens L)

Two seed lots of white clover (Trifolium repens L.) cultivar 'Makibashiro' classified as high and poor quality seed lots, based on the speed of germination (T50), were used to examine the influence of seed quality on field establishment and forage yield. Field emergence rate was estimated approximately three weeks after sowing and found that plots sown with high quality seeds (Lot 1) had 452 seedlings m(-2) compared with 392 seedlings in the plots sown with low quality seed lot (Lot 2), but the difference was not significant. However, plant density in autumn (November, 1993), 3 months after sowing, was significantly (P < 0.05) higher in the plots of the Lot 1 plots was 55% compared with 39% from the Lot 2 plots, but the difference was not significant. Total forage yield in Lot 1 plots harvested in July and monthly intervals to October, was significantly increased by 44% (P < 0.05) over that of Lot 2 plots, but this greater forage yield in high seed quality seed lot plots was produced early in the season. The results strongly imply that the primary advantage to be gained from high quality seed is an improved field establishment, which led to increased yield of clover. In lot 1 plots, the percentage of weed dry matter in all the four harvests remained below 1% of the seasonal dry matter production, whereas in Lot 2 plots the percentage of weed dry matter ranged from 3.3-16.9%.