Tomato fruits ripened 95, 65, 46 and 42 d after flower opening when plants were grown under controlled environmental conditions at 14, 18, 22 and 26 °C, respectively. A similar response to temperature was observed when the temperature of individual trusses was modified while the plants were grown at 20 °C. These data were used to develop a thermal time model for fruit maturation. However, when buds/fruits were heated at different stages in their development, the thermal time model proved to be a poor predictor of the time of ripening. Fruits were more sensitive to elevated temperature in their later stages of maturation. Temperature also affected the rates of fruit growth in volume; these could be adequately described using a Gompertz function. Low temperatures reduced absolute volume growth rates and delayed the time at which the absolute growth rate became maximal. However, the response of fruit growth to temperature differed when only the temperature of the fruits was modified. There was a tendency towards small parthenocarpic fruits at both high (26 °C) and low (14 °C) temperature regimes which, combined with low flower numbers and poor fruit set at 26 °C, resulted in low fruit yields. Temperature also affected the shoot dry matter content and partitioning. Copyright 2001 Annals of Botany Company

Received: 6 April 2001 ; Returned for revision: 1 June 2001 . Accepted: 13 July 2001


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