Altered flower retention and developmental patterns in nine tomato cultivars under elevated temperature

Moderately elevated temperature effects on flower development were examined in nine tomato cultivars (Lycopersicon esculentum Mill.). Plants were grown under high (HT, 32/28 degreesC day/night temperatures) and control (CT, 26/22 degreesQ temperature conditions. Fate of flowers developed was categorized as seeded fruit, parthenocarpic fruit, undeveloped flowers, or aborted flowers. Although HT decreased seeded fruit set in all nine cultivars, the degree of sensitivity and the pattern of reaction to the elevated temperature differed among cultivars. FLA7156 was the most tolerant cultivar, although under HT seeded fruit set was less than half that at CT (22.5% compared to 46.8%). The remaining cultivars had very few or no seeded fruit set at all at HT. The percentage of parthenocarpic fruit increased at HT compared to CT in all cultivars. Aborted flowers also increased in FLA7156, NC8288, NCHS I and NC46E, but did not change in 'Piedmont', NC279HS, and NC403HS, or decreased in 'Fresh Market 9' and TH318. Reduction of flower abortion and increase of parthenocarpic fruit set can be advantageous traits for breeding of high temperature tolerant tomato cultivars. (C) 2004 Elsevier B.V. All rights reserved.