Study on Thermotherapy Treatment Effects on Seed Germination and Vigor of Tomato Cultivars

Hot water treatment presents great potential on the alternative control of seed pathogens. This research aimed to study the relation of hot water treatment to germination and vigor of tomato seeds of 3 varieties, to identify maximum combinations of temperature and exposure time of seeds with no detrimental effect on germination and vigor. The experiment was conducted as factorial based on complete randomized design in 3 replications. The treatments were cultivar at 3 levels (Super Star, Super Urbana and Queen), temperature in 5 levels (48, 52, 56, 60°C and control) and time of treatment in 4 levels (10, 20, 30 and 40 minutes). The measured traits were germination percent, germination rate, and some seed vigor aspects including seedling radicle length and shoot length and seedling dry weight. The analysis of variance showed seeds treatment in temperatures of 56°C and 60°C for 30 and 40 min had detrimental effect on germination and vigor. There was a significant difference among cultivars in germination percent and germination rate, especially at higher temperatures. Queen cultivar showed better germination ability and Super Star was the most sensitive to high temperatures (56 and 60°C) and had the lowest germination ability and vigor.