Breeding Rubus for Warm Climates1

Abstract

Abstract Temperate climate blackberries and raspberries exhibit weak growth and sparse fruiting in Florida (6, 8) because insufficient chilling in winter is obtained for normal termination of rest. Florida's native blackberries have been harvested since pioneer days for jams, pies, and fresh use, but this industry has remained very small. Rubus breeding was initiated at the University of Florida in 1953 to produce better bramble cultivars adapted for growing in warmer climates. Few introduced species and cultivars have an inherent low chilling requirement with sufficient winter cold hardiness to survive in Florida. Native types produce small berries with fruit quality below commercial acceptability. Moreover, lack of flavor is recognized as a limiting factor in most of the low chilling germplasm, especially in the trailing blackberries and ‘Mysore’ raspberry. Two reviewers of the Rubus project, G. M. Darrow, 1957, and I. C. Haut, 1958, suggested that major efforts should be made to combine features of high fruit quality from the non-adapted temperate zone varieties with climatically adapted local types.