Sugar-beet seed advancement to increase establishment and decrease bolting

Abstract

SummaryExperiments with seed advancement and devernalization identified treatments which both increased rate of emergence and establishment and decreased bolting. Treatment temperature and duration were more critical for devernalization than for improving establishment. Exposing seeds to 15 °C for 6 days (at restricted moisture availability to prevent premature germination) sometimes promoted slight devernalization but sometimes enhanced bolting; 20 °C for 3 days had little effect whereas 20 °C for 6 days was moderately effective. The best treatment for both improving establishment and decreasing bolting was to steep the seed in water for 3 h at 25 °C, dry it to between 115 and 120% of its original air-dry weight, store it for 4 days at 25 °C and then air dry.Results in 1985 showed that the improvements are insufficient to allow sowing as early as 1 March. Following sowing on 17 March 1986, seed advancement increased establishment for two bulks of seed from 54 to 76% and from 63 to 77% respectively while bolting was decreased from 9·1 to 1·2% and from 5·9 to 0·7%. This suggests that in future it may be possible to recommend that sowing starts about a week earlier than at present.The results also suggested that only a previous vernalizing experience could be reversed. There was no indication that a devernalizing stimulus could be stored by seeds and used to offset the effects of cold after sowing. However, the best treatment in 1985 would have reversed a much more severe vernalizing stimulus than that likely to be encountered by the seeds while on their mother plant.