Occurrence of blossom‐end rot in tomato as a function of calcium dose in the nutrient solution and air relative humidity

Abstract

The effects of different calcium (Ca) concentrations in the nutrient solution and of air relative humidity (RH) on the Ca levels and on the incidence of blossom‐end rot in tomato fruit cv. Jumbo were studied. The experiment was conducted in a greenhouse under hydroponic conditions using a modified Hoagland solution containing different Ca concentrations (0.2, 2.5, 5.0, 10.0, 15.0, and 20.0 mm L^‐1) which represented the different treatments. The trial was conducted in a fully randomized design with three replications, with Ca doses representing the plots and environments with high and low RH the subplots. The fruits of the second and third clusters were used, with two fruits per cluster, one maintained at high (90±5%) and the other at low (40±5%) RH. The fruits were picked after full ripening. A greater Ca accumulation was observed in fruits submitted to low RH with this accumulation occurring at all Ca levels in the solution. In the treatment with 100 mg Ca L^‐1, the plants died and did not reach fructification. The fruits of plants treated with 100 mg Ca L^‐1 and submitted to low RH had blossom‐end rot although their Ca levels were higher than those detected in the fruits of this treatment submitted to high RH. At this Ca dose, the seeds were small, malformed, and black. Our results show that fruit kept at low RH had higher Ca accumulation although the excessive water loss from tissues may lead to blossom‐end rot when low Ca doses are supplied to the plants.