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Abstract
‘Georgiagem’, a new low-chilling cultivar. is the first highbush blueberry (Vacciniwn corymbosum L.) cultivar developed from the cooperative blueberry breeding program of the Georgia Agricultural Experiment Station and the USDA. Although ‘Georgiagem’ originated mostly from tetraploid highbush blueberry parentage, it obtained adaptation to the southern U.S. environment from the diploid species, V. darrowi, selected from the wild in Florida (2). ‘Georgiagem’ is early ripening, moderately productive, and has fruit of medium size with good color, small stem scar, firmness, and pleasant flavor.
Abstract
‘Patriot’ a new hardy blueberry, Vaccinium corymbosum L., originated in the cooperative blueberry breeding program of the Maine Life Sciences and Agriculture Experiment Station and the U.S. Department of Agriculture. It has performed well at Jonesboro, Maine, Maryland, North Carolina, and Oregon. The name ‘Patriot’ was assigned in recognition of the U.S. Bicentennial.
Abstract
The cover is a color photograph of a painting of a ‘Tristar’ strawberry plant by Lynda Chandler at the end of the Beltsville 1980 fall harvest season. ‘Tristar’ and its sister cultivar, ‘Tribute’, are new strawberry introductions from the U. S. Department of Agriculture — University of Maryland breeding program (see also p. 792–795 for more details). These cultivars are the first to combine red stele and verticillium resistance from octoploid cultivated strawberry cultivars with a strong, cyclic expression of the everbearing character from a wild selection of octoploid Rocky Mountain strawberry. ‘Tribute’ and ‘Tristar’ are related through a common grandparent to the ‘Brighton’, ‘Hecker’, and ‘Aptos’ day-neutral cultivars recently introduced in California by Bringhurst and Voth.
Abstract
‘Brightwell’ rabbiteye blueberry (Vaccinium ashei Reade) is a new cultivar originating from the cooperative blueberry breeding program of the Georgia Agricultural Experiment Stations and the U.S. Department of Agriculture. It is productive, early ripening, and has medium-size fruit with excellent color, stem scar, firmness, and pleasant flavor. ‘Brightwell’ is intended for those areas of the southern United States where rabbiteye blueberries are successfully grown. This cultivar is named in honor of W.T. Brightwell who bred rabbiteye blueberries for over 30 years at the Coastal Plain Experiment Station, Tifton, Ga. He is known for the many excellent cultivars that he and his cooperators originated.
Abstract
‘Spartan’ highbush blueberry (Vaccinium corybosum L.) is a new cultivar resulting from the cooperative efforts of Michigan grower Arthur Elliott, the Michigan Blueberry Grower’s Association, and the Science and Education Administration, of USDA.
Abstract
Chromosome pairing in a derived decaploid, 2n=10×=120, (from a colchicine-treated, sterile pentaploid hybrid of Vaccinium ashei Reade × V. corymbosum L.) was chiefly bivalent. Multivalent associations were present in 5 of 16 cells scored at metaphase I, but only 23 chromosomes of the 1,920 observed were involved in multiple pairing. Most of the cells at anaphase I (33 of 35 observed) contained lagging chromosomes which appeared to be non-disjoined bivalents rather than univalents. The decaploid was selfed and crossed with hexaploid, tetraploid, and diploid species. The mean number of seedlings produced per flower pollinated for each ploidy level was low, ranging from 0.04 to 0.09. The mean seedling number produced per self-pollinated flower was considerably higher, 0.92. The percent of pollen which stained in propionocarmine was 8% for the pentaploid parent, 62% for the derived decaploid and 99% for plants of V. ashei and V. corymbosum used as standards for comparison.
Abstract
A clone of the diploid blueberry species Vaccinium atrococcum Heller, was previously found to be highly resistant to the fungus tetraploid highbusy blueberry. The tetraploid V. atrococcum was highly root-rot resistant in a greenhouse study. It was crossed with ‘Earliblue’ and 85 seedlings were obtained. In general, the seedlings were fertile, had small, dark fruit with mild flavor, good scars and quite soft flesh consistency.
Blueberry selections Me-US 32 and Michigan Lowbush 1, and cultivars ‘Berkeley’, ‘Bluecrop’, ‘Earliblue’, and ‘Dixi’ were screened in the greenhouse for resistance to P. cinnamomi. Michigan Lowbush 1 was highly resistant to the root-rot fungus. Me-US 32 was resistant, but all the cultivars were susceptible. Michigan Lowbush 1 is a grandparent and probably the source of resistance of Me-US 32.
Abstract
The U.S. Department of Agriculture strawberry breeding program has introduced 61 cultivars from 6 breeding locations in its 61-year history. Fifteen to 20 of these cultivars have been widely grown, and 5 of the recent releases show exceptional promise. From its inception, the program has been aimed at producing high-quality, multipurpose cultivars with disease resistance and broad regional adaptation. Because of disease pressures, genetic resistance has been emphasized, especially for red stele root rot. The USDA has become the principal source of red stele-resistant germplasm for breeding pruposes, and has constantly refined and improved its disease-screening techniques. Red stele and Verticillium resistance have now been incorporated into everbearing strawberries adapted to the eastern United States. Investigations concerning virus detection and eradication and the propagation of virus-free stocks have led to state virus-free plant certification programs, which assure the public of production of the cleanest possible strawberry nursery stocks. The work of the USDA and cooperating state stations has played a significant role in the improvement of strawberry cultivars and the development of modern strawberry production in the United States.