Early- and mid-season temperature effects on the growth and composition of satsuma mandarins

SummaryThe growth and composition of satsuma mandarin fruit from trees which had been covered by a tunnel house during either stage one (the first ten weeks after anthesis), stage two (10±20 weeks after anthesis) or throughout fruit growth, were compared with those grown under ambient conditions. During each stage temperature was identified as the key factor influencing fruit development and changes to fruit were generally maintained when trees were returned to ambient conditions. Raising maximum air temperatures in the canopy of trees by 2.4.K during stage one increased both fruit growth rates and accumulation of sugars throughout their development. Titratable acidity levels were also increased and quinate levels decreased when trees were warmed during stage one, but these differences did not persist until harvest. Fruit grown under elevated temperatures during stage one had larger pedicels and dorsal vascular bundles, which suggests that temperatures during early fruit development determine the fruits' ...