Effects of Plant Density on the Maturity and Once-Over Harvest Yields of Broccoli

Abstract

SummaryA field study was conducted with two cultivars during 1976 and one during 1979. Plant densities from 2.1 to 98.0 plants m−2 were used and sequential harvesting during the maturity period was undertaken in 1979. Spear yield and maturity status changed continuously during the harvesting period depending on the relative proportion of spears becoming marketable and over-mature. For cv Futura sown in mid-January, harvesting for all densities can be confined to a three-day period from Day 87 to Day 90. A similar harvesting period would most likely be suitable for cv Gem. The marketable yield at this stage is about 10% less than the maximum marketable yield. For efficient processing in the factory, this reduction in yield is more than compensated for by minimizing the quantity of waste material harvested from over-mature plants. The form of the yield-density relationship indicates that spear yield approaches the asymptote at a relatively low plant density in all three cultivars (20 plants m−2). Consequently the most suitable plant density to be used could be determined by the size attributes required by the processing companies.