Effect of Different Amounts of Winter Chilling on Fruitfulness of Several Olive Varieties

Abstract

1. Inflorescence and subsequent fruit production in eight varieties of olives was, in general, directly proportional to the amount of winter chilling received. Trees of each variety maintained in a warm greenhouse throughout the winter failed to produce a single inflorescence. 2. The number of flowers per inflorescence or the percentage of perfect flowers produced was not affected by the amount of winter chilling 3. The varieties Ascolano and Sevillano required the maximum amount of winter chilling encountered at Davis, California, during each of two winters before appreciable amounts of inflorescences were produced 4. The varieties Mission, Criolla, Barouni, and Manzanillo produced some inflorescences with intermediate amounts of chilling, although considerably more developed with the full amount of chilling 5. In the 1956-57 tests the Rubra and Azapa varieties were able to produce substantial numbers of inflorescences under the minimum amount of chilling given, indicating that they might be adaptable to...