Data from a four-parent diallel, involving one highbush (Vaccinium corymbosum L.) clone and three interspecific hybrids grown on mineral soil unamended with organic matter, were analyzed to determine combining ability effects for six traits: plant size, berry size, the number of days between flowering and fruiting (# DBF&F), the ratio of total fruit weight to canopy volume (TFW: CYV), days to fruit ripe, and yield. General combining ability effects were significant for all characters tested, except yield and berry size in 1984. Specific combining ability effects were significant for plant size in 1983, #DBF&F in 1984, TFW: CYV in 1984, and berry size in 1985. Vigorous and productive highbush cultivars can be developed for mineral soils by using the interspecific clones from this study and their selected recombinant to combine the genes for plant vigor with the high-quality fruit traits of highbush cultivars.
W.A. Erb, A.D. Draper, G.J. Galletta, and H.J. Swartz
James N. Moore
The blueberry cultivar situation in North America is undergoing rapid change. Attempts to grow blueberries in non-traditional areas, and increased biotic and abiotic challenges in traditional production areas, are fueling the search for superior, adapted cultivars. This survey of all blueberry-producing states/provinces in the United States and Canada provides the current status and projected trends in blueberry cultivar use in North America. Most (86%) of current hectarage is comprised of 25 northern highbush, 10 rabbiteye, and two southern highbush cultivars. `Bluecrop' is the dominant northern highbush cultivar, with 35% of the highbush area, while `Tifblue' occupies 40% of the rabbiteye area. Some historically important cultivars, such as `Jersey', `Weymouth', and `Woodard' are in decline. New cultivars of all blueberry types are beginning to have a positive impact on the blueberry industry.
Lisa J. Rowland, Elizabeth L. Ogden, Mark K. Ehlenfeldt, and Rajeev Arora
‘Northsky’, which is three-fourths V . corymbosum and one-fourth V. angustifolium , were the most cold hardy with BCH levels less than −28 °C, the lowest temperature that our glycol freezing bath would reach. V. corymbosum and V. angustifolium are
Gad G. Yousef, Mary A. Lila, Ivette Guzman, James R. Ballington, and Allan F. Brown
, V. angustifolium, and V. virgatum ) and (increasingly) to transfer unique genes or chromosomal segments (introgressions) from the secondary gene pool (non-cultivated Cyanococcus species) ( Ballington, 2009 ; Brevis et al., 2008 ). However
Patricio A. Brevis, Nahla V. Bassil, James R. Ballington, and James F. Hancock
[ Vaccinium corymbosum (2n = 4x = 48)], lowbush blueberry [ V. angustifolium (2n = 4x = 48)], and rabbiteye blueberry [ V. virgatum (2n = 6x = 72)], whereas the remaining noncultivated Cyanococcus species constitute the secondary gene pool ( Lyrene and
J. J. Luby, D. K. Wildung, C. Stushnoff, S. T. Munson, P. E. Read, and E. E. Hoover
A blueberry (Vaccinium spp.) breeding program was initiated at the Univ. of Minnesota in 1967 using V. corymbosum L. and V. angustifolium Ait. and hybrids between the species. The objective was to develop low-saturated, high-quality, cold-hardy cultivars for commercial as well as home garden use (3). ‘Northblue’, ‘Northsky’, and ‘Northcountry’ are the first cultivars introduced from this program.
James N. Moore
Expansion of blueberry culture in North America has occurred during the past decade and is projected to continue into the next century. Thirty-six U.S. states and six Canadian provinces report some blueberry production. The area planted to blueberries has inreased by 19% in 10 years, with the largest increase (47%) in cultivated types and only 11% in wild blueberries. It is projected that the total area will increase by an additional 14% by the year 2000. New cultivars are proving of value and are affecting the composition of plantings. Greater interest is being given to mechanical harvesting, and new cultural and pest control innovations are being employed to enhance the economics of production. The expansion of blueberry production is being undergirded by expanded programs in problem-solving research.
M.K. Ehlenfeldt, A.W. Stretch, and V. Brewster
The resistance of 48 highbush blueberry cultivars and selections to the blight phase of mummy berry disease, incited by the fungus Monilinia vaccinii-corymbosi (Reade) Honey, was examined in relation to percent Vaccinium angustifolium Ait. ancestry, season of fruit maturity, and shoot growth during the primary infection phase. Correlations of percent blighting with percent V. angustifolium ancestry were significant across 3 years, but correlations with fruit maturity were significant in only 2 of 3 years. Correlations of percent blighting with early shoot growth were significant in both years measured, with r values of 0.54 in 1994, 0.83 in 1995, and 0.83 across years. A multiple regression found only shoot growth highly significant for susceptibility and rendered V. angustifolium ancestry and season of fruit maturity nonsignificant. Resistant cultivars exhibiting early shoot elongation suggest that resistance can be either biochemically or escape based.
H. A. Quamme, C. Stushnoff, and C. J. Weiser
The highbush blueberry cultivars, ߢRancocasߣ and ߢEarliblueߣ, failed to acclimate in time to avoid low temp injury to stems exposed above the snow level during the 1st year seasonal change in hardiness was studied. In the 2nd year, however, they hardened to temp as low as -40°C and survived the winter. Acclimation occurred earlier in a native selection of Vaccinium angustifolium Aiton and in ߢRancocasߣ. Selections of V. angustifolium and natural hybrids of V. angustifolium and V. cormybosum L. were found to be hardier than any of the highbush cultivars. A selection of V. constablaei Gray and V. membranaceum Douglas, respectively, were also hardier than the highbush types. A low temp exotherm was found to be present in blueberry stems, but it was associated only with xylem injury which was not as critical for survival as the bark tissues. The bark was injured at temp higher than the xylem and was not associated with any exotherm.
J.J. Luby and C.E. Finn
The intervals, in days, between 10%, 50%, and 90% ripened fruit, as well as crop load, were estimated over 2 years in progenies from a partial diallel cross among 17 blueberry (Vaccinium corymbosum L., V. angustifolium Ait., and V. corymbosum × V. angustifolium hybrids) parents. General combining ability (GCA) mean squares were highly significant for all ripening intervals and for crop load, while specific combining ability mean squares were nonsignificant, indicating a large proportion of additive genetic variance. Narrow-sense heritability estimates were about 0.50 for the three ripening intervals (10–50%, 50–90%, and 10–90%). Several parents had large positive GCA effects, indicating their contribution to a long ripening interval. Most progenies with large crop loads required >15 days between 10% and 90% ripened fruit. Despite the consistently positive relationship between ripening interval length and crop load, variation among families and the potential for within-family segregation suggest the possibility of obtaining genotypes with high yield potential and improved uniform ripening.