Hornby, C. A. and H. A. Daubeny.
In the winters of 1953-54 and 1954-55 tomato plants of the varieties Puck and Bonny Best were grown in greenhouses at the University of B. C. to study effects of temperature on pollen production and fruit set. Replicated experiments were carried out in (a) a cool house where temperature was maintained at or close to 50 deg. F and did not rise above 55 deg. F, and (b) a warm house held at 65-70 deg. F.
Puck flowered earlier and produced more blossoms per cluster than did Bonny Best. At the warm temperatures all flowers were normal and produced abundant pollen. At the cool temperatures, all Bonny Best flowers were fasciated, but only 5 out of 107 Puck flowers were slightly affected. About 25% of the Barny Best flowers had a small amount of pollen, and the remainder had none; whereas nearly 80% of Puck flowers had abundant pollen and the remainder had none. In flowers producing little or no pollen, meiosis was relatively normal in the pollen mother cells, and the degeneration of pollen usually occurred prior to anthesis. Two samples of pollen produced at the cool temperature averaged 24.9% viability for Puck and only 2.5% for Bonny Best. Germination of this pollen was difficult to ascertain, but when pollen of a given variety grown in the warm house was transferred to stigmas of the same variety grown in the cool house, an average of 87.5% of Puck and 33.0% of Bonny Best pollen germinated.
At the warm temperature, fruit set was heavy for both varieties. In the cool house, twelve plants of each variety which were tapped to assist pollination, set 313 Puck and 167 Bonny Best; &U of the Bonny Best and about 70% of Puck fruits were parthenocarpic. A similar group of plants, which had been treated with pollen grown in the warm house, set 553 Puck and 196 Bonny Best fruits; once more all Bonny Best fruits were parthenocarpic, and most of the Puck contained well developed seed. The seedless Puck fruits were the very small ones which were last to set on the clusters.
The data suggested genetic differences between Puck and Bonny Best in production of viable pollen, germination of pollen and fertilization at relatively cool temperatures.