Some effects of cool temperatures on flower production, pollen production and pollen germination in certain lines of the tomato (Lycopersicon esculentum, Mill.)

Most commercial tomato varieties require relatively high temperatures for fruit set and development, and this requirement limits tomato production in Canada. There are, however, certain newer varieties which are reported to set fruit at cool temperatures (below 55° F.). One such variety, Puck, a non-commercial type, was contrasted with the commercial varieties, Bonny Best and 498. Replicated field and greenhouse experiments were conducted to ascertain the fruit setting character of Puck, and cyto-logical and histological studies were done on some aspects of this character. The results are as follows. Puck flowered earlier and produced more blossoms than the commercial varieties and thus had a greater opportunity for fruit set at cool, temperatures. Individual Puck blossoms produced more pollen at cool temperatures than did the individual blossoms of the commercial varieties. The study on pollen formation in the different lines grown at the cool temperatures showed meiosis to be relatively normal in the pollen mother cells, and that pollen degenerated prior to anthesis. A much higher per cent of Puck pollen than Bonny Best pollen was able to germinate at cool temperatures, and fruit set at these temperatures was largely parthenocarpic. These results show that Puck has useful characteristics which contribute to fruit set at cool temperatures and which can be used in a plant breeding programme.Land and Food Systems, Faculty ofGraduat