Greenhouse tomato limited cluster production systems: Crop management practices affect yield

Limited-cluster production systems may be a useful strategy to increase cro p production and profitability for the greenhouse tomato (Lycopersicon escu lentum Mill). In this study, using an ebb-and-flood hydroponics system, we modified plant architecture and spacing and determined the effects on fruit yield and harvest index at two light levels. Single-cluster plants pruned to allow two leaves above the cluster had 25% higher fruit yields than did plants pruned directly above the cluster; this was due to an increase in fr uit weight, not fruit number. Both fruit yield and harvest index were great er for all single-cluster plants at the higher light level because of incre ases in both fruit weight and fruit number. Fruit yield for two-cluster pla nts was 30% to 40% higher than for single-cluster plants, and there was lit tle difference in the dates or length of the harvest period. Fruit yield fo r three-cluster plants was not significantly different from that of two-clu ster plants; moreover, the harvest period was delayed by 5 days. Plant dens ity (5.5, 7.4, 9.2 plants/m(2)) affected fruit yield/plant, but not fruit y ield/unit area. Given the higher costs for materials and labor associated w ith higher plant densities, a two-cluster crop at 5.5 plants/m(2) with two leaves above the cluster was the best of the production system strategies t ested.