ISHS Acta Horticulturae 565: VI International Symposium on Temperate Fruit Growing in the Tropics and Subtropics
BREEDING APPLES FOR WARM CLIMATES IN NORTHEASTERN MEXICO |
| Authors: | F.A.I. Rumayor, C.A. Martinez, R.J.A. Vazquez |
| Keywords: | low chilling requirement, subtropical climates, seed germination |
| DOI: | 10.17660/ActaHortic.2001.565.9 |
| Abstract:
The chilling requirement (CR) for most apple cultivars from temperate regions, is above 700 hours at 3-8°C. It is one of the factors limiting adaptation to areas with subtropical warm climates in Mexico. A breeding program was started in 1988 in Northeastern Mexico to develop apple genotypes with low chilling requirement, disease and pest resistance, and high quality fruit for the fresh market. The chilling requirement for germination of seeds from low and high chilling genotypes, crosses among them and F1 selections, was studied as a tool to estimate chilling requirement of the progeny. Speed of germination of seeds differed among hybrid families, ranging from 44 to 200 days. Pollen source affected seed chilling requirement during stratification. The germination period of seeds from the cross “Anna” x “Gala” had the widest range in chilling requirement. The seedlings derived from such crosses represent a good source for future selection in the subtropics, and some selections with chilling hours between 150 and 300 hours are described. | |
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