HIGH TEMPERATURE DAMAGE ENCOUNTERED BY TOMATO FRUITS AND THEIR SEEDS WHEN THE FRUITS ARE EXPOSED DIRECTLY TO THE SUN AND NOT COVERED BY PLANT FOLIAGE
Tomato (Lycopersicon lycopersicum Karsten) fruits from mother plants grown under partially-shaded conditions had a greater percentage of seeds with high germination capability than seeds from fruits that were exposed to the sun. Typical temperatures in exposed tomato fruit in the field on a sunny day were about 40°C whereas the temperature in shaded fruit was usually 10 degrees lower. The adverse effect on seed vigour of the high temperatures in the fruit in the field could be overcome by a healthy foliage cover, or artificially, by partially shading the tomato plants with the quickly growing vegetation of scarlet runner bean (Phaseolus coccineus) seeded on both sides of the row of tomato plants 3 weeks after tomato transplant setting in field. Under controlled laboratory conditions, seeds from tomato plants grown at 36°C day temperature had lower seed vigour than those grown at a 24° temperature. Vigour of seeds from tomato fruits that matured at temperatures of 35°C and higher decreased as the temperature increased.
Liptay, A. and Moore, L.A. (1989). HIGH TEMPERATURE DAMAGE ENCOUNTERED BY TOMATO FRUITS AND THEIR SEEDS WHEN THE FRUITS ARE EXPOSED DIRECTLY TO THE SUN AND NOT COVERED BY PLANT FOLIAGE. Acta Hortic. 253, 225-232