Comparative Floral Fertility in Heat Tolerant and Heat Sensitive Tomatoes1

Abstract

Abstract The heat tolerant tomatoes (Lycopersicon esculentum Mill.) breeding line AU 165 and ‘Nagcarlang’ were compared with the heat sensitive ‘Floradel’ in fruit set, pollen abortion, and embryo sac abortion. The 2 heat tolerant cultivars had a significantly higher percentage fruit set under both moderate and high temperature in spring and summer than did ‘Floradel’, but fruit set of all 3 cultivars was significantly lower at high temperature. The fruit set of all 3 cultivars was markedly improved by hand pollination, indicating that insufficient pollination probably was a major cause of heat sterility at high temperature. Both pollen and embryo sac abortion were minor factors in the reduced fruit set observed. Heat tolerance in the cross AU 165 × ‘Floradel’ appeared to be partially dominant.