Improved drought tolerance and root development as components of a scheme to breed blueberries for mineral soil adaptability

Blueberry breeding in North America started at the beginning of the 20th century and present cultivars are adapted to irrigated, high organic, acidic, sandy soils. However, sites meeting these requirements are limited, which has forced breeders to develop germplasm that is adapted to unamended mineral soils. Wild Vaccinium species can be found growing on a number of different soil types under a variety of climatic conditions, which indicates that genetic variability for mineral soil adaptability is present in Vaccinium germplasm. However, for a number of reasons progress in the development of mineral soil-adapted blueberry cultivars has been slow. In this paper a breeding scheme is presented that would allow the user to more efficiently access the variability that exists for mineral soil adaptability. The scheme is composed of two different seedling screening techniques (drought and seedling rooting screen) that are designed to eliminate the less vigorous individuals in a population before field testing. The field environment would be used primarily to evaluate individuals for fruit quality and yield characteristics. In blueberries, both general and specific combining ability can be fully exploited because they are vegetatively propagated which immediately fixes any unique combination of genes.