ROLE OF EXCESS WATER IN TOMATO FRUIT CRACKING

Excess irrigation water was provided to spring crops of bag-grown greenhouse tomatoes (Lycopersicon esculentum Mill.) to test the effect on radial fruit cracking. Varied numbers of emitters were placed in bags filled with soilless medium to provide different amounts of irrigation water, In 1990, all emitters provided water containing nutrient solution, but in 1992, the extra water added in one treatment did not contain nutrient solution, In both years, the percentage of cracked fruit was 20 percentage points higher in the treatments receiving more waiter, The increase in cracking was similar whether or not nutrient solution was added to the extra water, There also were some effects of the extra water on yield, Fruit count per plant was slightly higher (9.5%) when extra water was provided without nutrient solution, but was the same when nutrient solution was added to the extra water, Fruit weights per plant were 18.6 % higher in 1990 when watering was increased, In 1992, fruit weights were similar, except for the treatment where the extra water provided did not contain nutrient solution, Fruit weight in this treatment was 19.7 % higher than in the other treatments. In both crops, the percentage of cracking increased as linear and quadratic functions of cluster positions, i,e., there was more cracking in the upper clusters, In greenhouse situations, growers should consider water reduction when experiencing high levels of fruit cracking and as a precautionary measure when harvesting from the upper clusters, Providing excess water to greenhouse-grown tomatoes may be a viable technique for screening cultivars or for conducting research on practices to reduce cracking,