Effect of day and night temperature on pollen characteristics, fruit quality and storability of tomato.

Tomatoes (Lycopersicon esculentum) were grown to extremely high day and low night temperatures (day/night temperatures of 27/14˚C and 30/11˚C) with constant average temperature. This was done by keeping greenhouse closed during daytime to utilize heating from solar radiation to prevent the negative effect of low night temperature. Tomato plants of cultivars Capricia, Mecano and Cederico were grown under low night temperature and high day temperature and flowers were analyzed one and four day after flower opening. This showed positive effect on pollen production and pollen germination percentage when compared with normal growing day/night temperature conditions (24/17˚C). Varieties show similar effect on pollen production and viability. High day temperatures treatment prevents the effect of lower night temperature in pollen quality and viability which also showed higher performance than the normal growing temperature conditions. At harvest, increase in temperature difference from 24/17˚C to 24/17˚C had positive effect on fruit firmness and decrement on further increase in temperature difference. Furthermore, dry matter content, soluble solids and titrable acidity is found to be decreased with increase in temperature range. pH content was higher in tomatoes grown in higher temperature regimes. Significant difference in firmness, dry matter content, soluble solids, titrable acidity and pH could be seen in different varieties and Capricia had shown better quality characteristics followed by Mecano and Cederico respectively. Storing tomatoes at 13˚C could not show predominant effect on dry matter, soluble solids, titrable acidity and pH but firmness shows negative effect during storage with increase in preharvest day and night temperature difference treatments. The results presented could support the development of novel procedure for producing greenhouse tomatoes with minimum energy consumption for heating during winter nights.