Blueberry Hybrids with Complex Genetic Backgrounds Evaluated on Mineral Soils: Stature, Growth Rate, Yield Potential and Adaptability to Mineral Soil Conditions as Influenced by Parental Species

Abstract

A population of 54 blueberry ( Vacciniumsubsection Cyanococcus) cultivars or interspecific hybrid selections derived from combinations of nine Vacciniumspecies were evaluated in replicated trial for their mineral soil adaptation response. Individuals within the population varied significantly for the following objectively-measured traits: plant form (height and volume), growth pattern and rate (canopy volume increase over time) and fruit yield/volume. Subjective evaluations also uncovered a high level of variability among genotypes for vegetative vigor (the ability to produce new shoots in proportion to existing plant mass), fruit/foliage ratio (the ability to balance fruit production and vegetative/floral growth/induction) and freedom from foliar nutrient deficiency symptoms. Indices based on subjective evaluations and compared to objective measurements indicated the following genotypes to exhibit a moderate degree of mineral soil adaptation: Jersey, Sunrise, US 612, 645, 665, 673, 676, 693, 702, 714, 723, 730, 845 and 848. When genotypes were grouped according to their genetic constitutions, significant heritage effects were found for plant height, fruit yield/volume, 1995 and 1996 vegetative vigor scores and 1995 fruit/foliage ratios. However substantial within group variability for all traits was evident, suggesting that mineral soil adaptation can be derived from a number of species combinations. Although some deleterious patterns in growth and yield potential can be anticipated when interspecific hybridization is used within a blueberry breeding program, unique individuals do appear which have captured beneficial traits (such as mineral soil adaptation) from feral species.