INDEXES OF TOLERANCE OF TOMATO (Lycopersicon esculentum Mill.) SEEDS FOR GERMINATION AT LOW TEMPERATURES

Sixteen tomato (Lycopersicon esculentum Mill.) cultivars from Poland and China were tested on their seed tolerance to germinate at low temperatures: 15ºC and 10ºC. Their responses were evaluated based on 4 characters: germination energy, germination capacity, maximum germination and fresh weight of 100 normal seedlings, calculated then into 6 different indexes. All of proposed indexes include the optimal temperature of germination (20ºC). There is a possibility to use the suggested indexes to evaluate seed tolerance of various tomato cultivars to germinate at low temperatures. The tested low temperatures decreased the germination energy of the seeds of the tested tomato cultivars. Three cultivars were found with a satisfactory germination at 15ºC, but at 10ºC the germination of all tested cultivars was poor. The biggest tolerances of seeds to germinate at 15ºC was found for the cultivars: 'Kibic', 'Maliniak' and 'Etna F₁', the smallest – for the cultivars: 'Bai Guo Qiang Feng' and 'Sheng Li 919'. The biggest tolerances of seeds to germinate at 10ºC was found for the cultivars: 'Batory F₁' and 'Korsarz', whereas the smallest – for the cultivars: 'Etna F₁', 'Poranek', 'Maliniak', 'Kora', 'Bursztyn', 'Sheng Li 919', 'Ju Huang 83-3' and 'Bai Guo Qiang Feng'.