SPACING, ROOT CELL-VOLUME, AND AGE AFFECT PRODUCTION AND ECONOMICS OFCOMPACT-GROWTH-HABIT TOMATOES

Compact-growth-habit (CGH) tomatoes (Lycopersicon esculentum Mill.) do not require the pruning, staking, and tying required for many fresh-m arket tomato cultivars. In 1990, 5-week-old transplants of the CGH tom ato breeding line NC 13G-1 were grown in single rows with in-row spaci ngs of 31, 46, 61, and 76 cm and in double rows with in-row spacings o f 31 and 46 cm. NC 13G-1 produced high early and total season marketab le yields when grown in either double-row treatment compared to any si ngle-row treatment. In 1991 and 1992, 4- and 5-week-old NC 13G-1 trans plants were produced in five root cell volumes (8.6, 13.6, 27.0, 37.1, and 80.0 cm3), transplanted into double rows with an in-row spacing o f 46 cm, and evaluated for yield. Five-week-old transplants produced i n 37.1- and 80-cm3 cells flowered sooner after transplanting and produ ced higher early season yields than 4-week-old transplants produced in the three smaller cells. Midseason yields increased quadratically and late-season yields decreased quadratically as root cell volume increa sed. Total season marketable yields did not differ among treatments. I n 1991, production costs were influenced by root cell volume, but not in 1992. In 1992, net returns for the four smallest cell volumes were similar, and lower than for transplants grown in the largest cell volu me. In both years, highest net returns were achieved with transplants produced in 37.1-cm3 cells. Considering the estimated 1992 net returns of $17,000/ha, production of CGH tomatoes may provide an alternative for staked-tomato growers concerned with labor availability and produc tion costs, even though marketable yield from NC 13G-1 was lower than with a conventional cultivar under the standard system.