Interaction effect of irrigation, calcium and nitrogen on tomato blossom end rot disorder

Tomato (Lycopersicon esculentum Mill.) is the second most important vegetable in the world. Blossom end rot as a physiological disease is one of the major limitation in tomato production. Therefore, this study was carried out to evaluate the effect of irrigation regimes, calcium chloride and urea on control of blossom end rot under field condition. A factorial experiment was conducted based on completely randomized design with 18 treatments and 4 replications at the Agricultural Research Station of Bushehr province, Iran in 2014. Studied factors were irrigation rate (daily, every two and three days), calcium chloride application (0, 5 and 10 ppm as foliar application) and urea fertilizer (control and 3 grams per pot). The results showed that the interaction of three studied factors on the blossom end rot was not significant. However, the interaction of irrigation × calcium chloride as well as the main factors was significant on the control of blossom end rot. So that, the highest level of blossom end rot was observed in the control (no calcium) and irrigation for each two days. While, the highest control of the disease were treated with daily irrigation regime with the use of calcium chloride (especially at a concentration of 10 ppm). The disease index decreased from 4.5 (in control treatment) to 0.5 in the daily irrigation regime when calcium chloride was used. Also, the results showed that the application of the appropriate level of urea fertilizer can significantly reduce this physiological disorder.