THE EFFECT OF AUXIN, GIBBERELLIN AND VIBRATOR ON GREENHOUSE TOMATOES FRUIT-SETTING AND YIELD IN MILD WINTER CLIMATIC CONDITIONS

During winter in Portugal tomatoes are mainly cultivated in green-houses with no heating, therefore plants are subjected to moderate cool temperatures during part of their cropping cycle.
An experiment was conducted under these conditions, in order to improve fruit-setting.
In 1980/81 and 1981/82 4 treatments (auxin, gibberellin, auxin + gibberellin and vibrator) were applied to flowers of 2 tomato cultivars in 2 plastic greenhouses, from November to June, one with 12°C minimum air temperature and the other with no heating.

Yields of non heated plants were bigger, as they bear higher numbers of flowers and fruits, but the harvest was rather delayed in the cool greenhouse.
Auxin and vibrator increased fruit size and yield, but decreased the amount of fruit.
Gibberellin induced the highest fruit – setting but with very small fruits.
With low temperature but enough light, the percentage of parthenocarpic fruits was fairly high.
But it decreased with higher temperature and etiolated plants, as sometimes happens in the heated greenhouse.

International Symposium on Protected Cultivations in the Mediterranean Regions

A.A. Monteiro

https://doi.org/10.17660/ActaHortic.1986.176.18