BRUSHING INFLUENCES TRANSPLANT GROWTH AND SUBSEQUENT YIELD OF 4 CULTIVARS OF TOMATO AND THEIR HYBRID LINES

Pot-grown seedlings of seven lines ['Red Cherry' (RC), 'Moneymaker' (MM), 'Dantobi-yohzu' (DY), 'Furikoma' (FK), RC x FK, MM x DY, and MM x FK] of tomato (Lycopersicon esculentum Mill.) were brushed with a suspended steel bar for 1.5 minutes twice daily for 18 days (short-term treatment) before being transplanted to beds in a plastic greenhouse. Brushing was continued on a selected group of plants for an additional 10 days (long-term treatment). Short-term brushing slightly reduced the number of leaves, but markedly reduced leaf size and stem elongation of all lines. Dry weights of lamina, petioles, and stems of brushed plants of each cultivar except FK were less than those of the respective controls. However, the ratios of root : shoot dry weight of brushed plants were unchanged or higher than those of the respective controls. Short-term brushing did not increase the total number or weight of tomato fruits harvested over 1 month and did not improve fruit quality, size, or color. Long-term brushing reduced the total yield (number and weight) of fruits of RC and total fruit weight of DY. With respect to sensitivity to mechanical stress, cultivars with taller growth habits were more responsive to brushing than were those with shorter growth habits. These characteristic responses to mechanical stress also were exhibited by the hybrid lines.