Comparisons of the effects of harvesting sugar-beet seed by the traditional method of tripodding with barn drying, swathing followed by threshing with a pick-up combine or desiccation with diquat followed by direct combine harvesting showed that there were no consistent or large effects on seed yield, germination, monogermity or size distribution. Thus the best method will be the one which is easiest and/or cheapest, which at present is swathing followed by pick-up combine threshing.

Sprays of NAA or 2,4,5-T at 10 or 100 mg a.i./l water before or after flowering had no effect on seed yield or germination and efforts to restrict the loss by shedding of large viable seed failed. Neither chemical decreased germination percentage by setting parthenocarpic seed. Attempts were made to dwarf the 2 m high seed crop to make it suitable for direct combine harvesting. Daminozide sprayed at 1000, 5000 or 10000 mg a.i./l water before or after the winter did not affect plant height, seed yield, germination, monogermity or size distribution. Chlormequat chloride applied similarly dwarfed plants by up to 18% but this was not enough to give a crop less than 1 m high suitable for direct combine harvesting. It did not affect seed yield, germination, monogermity or size distribution. Ethephon sprayed at 10, 100 or 1000 mg a.i./l water when plants were bolting had no detected effects. Chlorflurecolmethyl was sprayed at 10 or 100 before bolting or 1, 10 or 100 mg a.i./l water afterwards. Plants sprayed with the 100 mg/1 solution were dwarfed to less than 1 m high but the treatment was unsuccessful because it greatly reduced seed yield and germination; monogermity was not affected but a much greater proportion of seed fell into the small size grades.