Plant Populations and Row Widths for Diploid Sugar-beet Varieties.

Abstract

The aim of this work was to see whether the introduction of diploid varieties, with their more erect leaf growth, would require any adjustment of the traditional plant spacing and row width recommendations for sugar beet. Five trials were carried out in 1996-98 in which the diploid variety Celt was sown at three row widths: 51, 56 and 61 cm. At each row width, seed spacings were adjusted to give four plant densities between 30,000 and 89,000 plants/ha. In four of the trials, field establishment was between 75 and 90%. In these trials, there was a slight increase in sugar yield with population up to 75,000 plants/ha, and little or no change above this level. There was a slight increase in extractability at higher populations, but not sufficient to have a significant effect on extractable sugar yield. In one trial where plant establishment was reduced by very cold weather, yield and sugar content continued to increase up to the highest plant count of 65,000 plants/ha. Over the five trials, there were no yield or quality differences between 51- and 56-cm rows. There was a reduction of 3.5% in extractable sugar yield in 61-cm rows, though this reached statistical significance in only one trial. Taking into account the high emergence that is normally achieved with diploid varieties, these results suggest that no change should be made to the seed spacings currently recommended for triploid varieties. For those using 61-cm rows, a small yield increase could probably be achieved by reducing row width.