'Endura' caucasian clover: progress towards commercial seed production

A series of seed production trials was established at Kimihia Research Centre, Lincoln, Canterbury to investigate row spacing sowing date and sowing rate requirements for Endura, the hexaploid cultivar of caucasian clover. In 1991 a trial with 30 cm or 45 cm row spacings with a sowing rate of 8 kg/ha coated inoculated seed was used. Although there were no significant differences in the first year (101 kg/ha cf. 111 kg/ha), the 45 cm row spacing yielded significantly higher than the 30 cm row spacing, in the second year (709 kg/ha cf. 371 kg/ha). Wider rows produced more flowers per unit area - 448 m-2 for 45 cm compared with 288 for 30 cm. In 1992 a sowing rate trial was established using 2 kg or 6 kg/ha of coated and inoculated seed in 45 cm row spacings. The lower sowing rate treatment of 2 kg/ha produced a significantly higher seed yield, of 208 kg/ha. The effect of sowing date (December, January, February) on seed yields was investigated. All sowing date treatments were sown at 6 kg/ha in 45 cm rows. The highest seed yield of 126 kg/ha was from January sowing. Weed seed content in the field-dressed samples harvested was associated with sowing date and decreased with each progressive sowing. The results indicate a strong negative correlation between plant density and seed yield. With early sowing, weed control is vitally important for successful seed production. Keywords: row spacing, seed yield, sowing date, sowing rate, Trifolium ambiguum