Tomato Fruit Development under Summer-to-autumn Temperature Conditions with Different Planting Seasons and in Each Fruit Truss

Abstract

Effects of temperature conditions on fruit development were examined in tomato (Solanum lycopersicum L.) with different planting seasons and in each fruit truss. Nine cultivars were planted in July and September in 2014 and 2015. The period during anthesis and fruit set (fruit-set stage) was longer, and the period during fruit set and break (fruit-development stage) was significantly shorter with July planting than September planting for all cultivars at both years tested. The fruit weight, diameter, and number of seeds were reduced significantly in most cultivars with July planting compared with September planting. Additionally, with July planting in both years, more than half of the cultivars showed a significant increase in the production ratio of small fruit (less than 50 g). The cultivars showing a markedly decreased fruit weight with July planting also showed a markedly reduced number of seeds, and the number of days in the fruit-set stage was much higher and that in the fruit-development stage was much lower. In the cultivars, the fruit weight was markedly reduced in the first truss with July planting in both years tested, and the temperature of the fruit-set stage was higher in the first truss. The fluctuations in the fruit weight and seed number of each fruit truss were correlated with the temperatures of the fruit-set stage of each fruit truss with July planting. In this experiment, it was considered that the decrease in fruit development with July planting was correlated with the seed number and days of the fruit-development stage, and strongly affected by the temperature of the fruit-set stage.