Next steps in breeding for yield in raspberries

Research and breeding for yield components has indicated that cultivars could have the potential to produce 66 t ha-1. This is realized when fruit size, number of fruits per lateral, number of laterals per cane and number of canes m-2 are combined. Raspberries consistently produce many more fruit bud initials than ever produce fruit. These initials act as photosynthetic sinks, so the issue for the future is to produce and move the carbohydrates to those initials. When the yields of raspberries and blackberries are compared blackberries consistently yield more than raspberries. A comparison of the two species indicated that blackberries produce fewer vegetative canes, retain their leaves longer, and have a better photosynthetic profile than raspberries. The potential to improve these traits in raspberries is discussed.