Plant Population and Spacing Effects on Processing Tomato Growth and Yield

Abstract

Processing tomato (Lycopersicon esculentum Mill.) producers in the Great Lakes region have expressed interest in cutting crop establishment costs and improving profitability by reducing plant populations. This study compared plant development, fruit set, fruit size and yields using a range of single and twin-row plant populations (14,800 to 44,500 plants/ha) and four commercially important processing tomato cultivars (`OH8245', `H9036', `PS696', and `H7135') with differing vine types and maturities. The 3-year study was conducted at Fremont, Ohio, on a Colwood fine sandy loam, using raised beds and other standard cultural practices. Six- to seven-week-old transplants (288 cell size) were mechanically planted in middle to late May. Once-over harvest was timed to achieve 80%–90% red fruit, using a Johnson tomato harvester. Plant population had a significant effect on 1995 fruit yields for all cultivars tested. Optimum red fruit yields were observed at 37,100 plants/ha in twin-rows for `OH8245', which was similar to 1994 results. Optimum fruit yields for `PS696' were obtained at twin-row populations of 29,600-44,500 plants/ha in 1995. Three year results for `OH8245' (medium-sized vine) indicate no significant differences due to plant population or arrangement. Mean red fruit yields varied considerably by year in this field research (62.7, 95.2, and 44.8 MT/ha in 1993, 1994, 1995 respectively), but twin-row spacing of `OH8245' provided significant yield gains in 2 of 3 years for populations of 29,600 plants/ha or greater.