Environmental and physiological effects on cuticle cracking in tomato

Tomato (Lycopersicon esculentum Mill.) cultivars and breeding lines were evaluated in the field for incidence and severity of cuticle cracking (CC) over four spring seasons at Bradenton, Fla. Resistant and susceptible genotypes were identified and easily distinguished by incidence of CC. When studied over 2 years, the amount of rain during the entire 14 days before harvest was more highly correlated with CC incidence than the amount of rain during the entire growing season or during 1 to 7 or 8 to 14 days before harvest. Attempts to induce CC by pruning leaves or fruit from plants were not successful. The incidence of CC was significantly higher for fruit from unstaked plants (39%) compared to fruit on staked plants (10%). Fruit exposed to direct sunlight, from plants that were staked and not pruned, had significantly greater incidence of CC (49 %) than fruit protected by leaf cover (20 %). Of 218 fruit monitored for affect of developmental stage on occurrence of CC, 62 developed CC. Of these 2%, 61%, 27%, and 10% first exhibited CC at immature-green, mature-green, breaker, and red stages, respectively. For 58% of fruit with CC, no increase in CC severity was observed as the fruit ripened. Increases in CC severity were observed more often between mature-green and breaker than between breaker and table-ripe stages of ripening.