Effect of high temperature on quality of processing-tomatoes of various genotypes ripened on the vine

High-temperature effects on tomato fruits of various genotypes ripened on the vine in the greenhouse were studied. A significant reduction in fruit quality was found in fruits ripened in a greenhouse where the temperature was greater than 30°C for an average of 9 h/day. The parameters studied included colour, total soluble solid content and acidity. There was no significant change in the major carotenoid pigments concentrations in these fruits compared with fruits ripened at optimal temperatures. This finding was not in agreement with that obtained in an earlier study using detached fruits ripened in incubators. Diurnal temperature fluctuation and translocation processes in the plant are suggested as the major factors accounting for these differences. “White tissue”, a colour disorder, was a major factor affecting fruit quality at high temperature. Fruits of a breeding line UCX100 15-2-2 had the highest quality, did not develop colour disorders and were relatively insensitive to high-temperature effects.