Formation of parthenocarpic fruit, undeveloped flowers and aborted flowersin tomato under moderately elevated temperatures

Incidence of parthenocarpic fruits undeveloped flowers and flower abortion in tomato plants (Lycopersicon esculentum Mill.) were compared under optima l temperature (OT, 28/22 degreesC day/night) and chronic, mild high tempera ture conditions (HT, 32/26 degreesC). Seeded fruits were found only under O T conditions, where 37 +/-9% of all flowers developed into seeded fruit. Ho wever, flower aborted was also higher under OT, with an additional 24 +/-7% of flowers aborted under optimal temperature conditions, compared to only 4 +/-1% of flowers aborted under HF conditions. Under HT most flowers (53 /-8%) developed into parthenocarpic fruits and the remainder (43 +/-7%) sta yed on the plant as undeveloped flowers. A slow transition of undeveloped f lowers to parthenocarpic fruit was also observed under HT. Factors determin ing whether flowers abort, develop parthenocarpically, remain on the plant without developing further, or develop into seeded fruit were discussed in relation to carbohydrate availability and the presence of seeded fruit on t he vine. (C) 2001 Elsevier Science B.V. All rights reserved.