The effect of plant density, date of apical bud removal and leaf removal on the growth and yield of single-harvest Brussels sprouts (Brassica oleraceavar.gemmiferaD.C.): II. Variation in bud size

Abstract

SummaryA method is suggested for estimating the mean bud size and standard deviation of a sample of sprout buds, separated into size grades by the use of riddles. From the standard deviation a potential size fraction is estimated, being the fraction of the buds occurring in a size grade of 10 mm width if the mean bud size were located at the mid-point of the grade. This estimate of bud size uniformity was independent of date of sampling for a period of at least 4 weeks.The potential size fraction was increased by stopping (apical bud removal) and in some cultivars an optimum stopping date was indicated. Increased plant density also increased the potential size fraction, particularly in unstopped crops. Between-plant variation in bud size was significantly greater for the hybrid Thor than the outpollinating Seven Bills but within-plant variation was the more important component of overall bud size variation and was greatly reduced by stopping and by increased plant density in unstopped crops. Mean bud size at any harvest date was increased by early stopping and lower plant density.It is concluded that the date of stopping should be chosen to minimize bud size variation and the plant density varied to spread maturity.