ISHS Acta Horticulturae 232: International Workshop on Apple Culture in the Tropics and Subtropics
LOW CHILLING AND DISEASE RESISTANCE AS MAIN OBJECTIVES OF APPLE BREEDING IN SANTA CATARINA, BRAZIL |
| Authors: | F. Denardi, L.F. Hough, J.I.d. Bonetti |
| Abstract:
In the unique climate of the highlands of Santa Catarina none of the commercial apple cultivars introduced from North Hemisphere is wholly satisfactory. There is an important commercial production in Santa Catarina at elevations between 800 and 1 000 m. In this area there is a considerable fluctuation of the temperature during each winter, and also from winter to winter. However, the average winter chilling is about 550 hours ≤ 7,2°C. The average annual rainfall is 1 600 mm. Promising parents have been identified which segregate for local adaptation and for desirable fruit. Disease control is the most costly factor in apple production. Sources of high resistance to the most important diseases, especially the Vf gene for scab, and the Pl1 and Pl2 for powdery mildew, have been introduced and used in breeding. Effective screening procedures for eliminating susceptible seedlings at an early stage are being used. Preselection techniques for the elimination of seedlings with undesirable vegetative characters are being used in the nursery during the first two growing seasons. Approximately 15% of superior individuals from the original seedling population are carried forward for fruiting. Grafting these superior seedlings on established M-9 rootstocks greatly accelerates first fruiting. Two new apple cultivars were released from this apple breeding project. 'Princesa', a very low chilling cultivar, has red-striped fruits with sweet-subacid flavor. The fruits ripen a month before Gala and the trees are very productive. 'Primicia', a Vf scab resistant cultivar, has also red-striped fruit. It is a low chilling, highly productive cultivar. The fruits ripen before Gala. | |
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