Intractable traits in Eastern U.S. blackberries

Abstract

Eastern U.S. blackberries are heterogeneous tetraploids. Some traits have been quite difficult to improve, and the example of erect-caned, thornless cultivar development is a good example. Thornlessness was associated with semi-erect canes, poor seed germination, and other undesirable traits, thus extending the amount of time to achieve an erect-caned, thornless cultivar. The first release of this type was 'Navaho' in 1989. Primocane fruiting is a trait that would not likely be considered intractable, but did not gain substantial attention until the late 1980s. Subsequent work in primocane fruiting has shown substantial progress in a relatively short time of breeding emphasis for this trait. Fruit size gains have been substantial, and even though this trait might be considered intractable, progress has been significant in the last 40 years. Excellent postharvest handling and flavor are additional traits which one might consider intractable. Substantial progress has been made in improving fruit quality for shipping, providing for an expansion in fruit shipped to distant markets. These and other improvements are expanding opportunities for blackberry growers worldwide.