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- Author or Editor: P.M. Lyrene x
- Journal of the American Society for Horticultural Science x
Diploid plants in Vaccinium section Cyanococcus, including plants of V. darrowi Camp, V. atrococcum. Heller (diploid V. corymbosum L.), a V. atrococcum × V. darrowi F1 hybrid, and a V. atrococcum × V. elliottii Chapmn. F1 hybrid, were hand pollinated in a greenhouse with pollen from diploid V. arboreum Marsh. (Section Batodendron). The resulting seeds were germinated and the seedlings were transplanted to a high-density field nursery. Forty of these F1 intersectional hybrids were selected after 2 1/2 years and transplanted to a 1.5 × 4-m spacing. Most of these plants were vigorous and flowered heavily in subsequent years, but only a small percentage of the flowers produced fruit. In 1990, however, >4000 berries were harvested from the 35 surviving plants. Open-pollinated seed from a much smaller number of berries was planted in Dec. 1987; these seeds produced ≈200 seedlings, some of which had moderate to high fruit set in a field nursery in 1989. Six of these seedlings, which were selected for high vigor, high fruit set, and characteristics intermediate between section Cyanococcus and section Batodendron, had fruit set ranging from 19.4% to 92.7% when pollinated with pollen from tetraploid V. corymbosum cultivars. One of the six seedlings was highly self-fruitful, and some intercrosses among the six seedlings produced much viable seed. Large-scale introgression of V. arboreum genes into tetraploid highbush cultivars likely will be possible by the methods used in this study.
Abstract
Shoots from tissue culture of 2 rabbiteye blueberry (V. ashei Reade) cultivars had smaller leaves, thinner stems, shorter internodes, and rooted faster than shoots from field-grown plants of the same cultivars. Rooting of cuttings taken directly from tissue culture or from 3-month-old tissue culture-derived plants averaged 95% for ‘Beckyblue’ and 96% for ‘Bluebelle’ after 19 days compared to 7% for ‘Beckyblue’ and 0% for ‘Bluebelle’ for softwood cuttings from field-grown plants. At 41 days, 100% of the cuttings taken from tissue culture or from tissue culture-derived plants had roots as compared to 54% for cuttings from field-grown plants.
Abstract
The effects of cross-pollination, self-pollination, and mixed (self plus cross) pollination of ‘Sharpblue’ blueberry (primarily V. corymbosum) were studied. The pollen for cross-pollination came from V. corymbosum clones ‘O’Neal’ and ‘FL 2-1’. Self-pollination resulted in 37% fruit set, compared to 74% to 91% set for the other pollination treatments. The number of well-developed seeds per matured berry averaged 3.5 for self-pollination, 13.0 for mixed pollination, and 24.4 for cross-pollination. The number of days from pollination to ripe fruit was highly and negatively correlated with berry seed number, regardless of the pollen source. Mixed pollinations delayed ripening an average of 7 days compared to cross-pollination, and self-pollination delayed ripening by an additional 13 days over mixed pollination.
Abstract
The purpose of this study was to compare the relative fecundity of tetraploid × hexaploid and hexaploid × tetraploid crosses in blueberry. Four types of crosses were made using cultivars and advanced breeding lines consisting largely of V. ashei Reade (6×) and V. corymbosum L. (4×). Fruit set, number of developed seeds per ripe berry, and number of seedlings per pollinated flower were determined. Tetraploid × hexaploid crosses averaged as high in percent fruit set as tetraploid × tetraploid crosses, but seed number per ripe fruit was only 29% as high and seedling number per pollinated flower only 35% as high. Hexaploid × tetraploid crosses, by contrast, set only 48% as much fruit as hexaploid × hexaploid crosses. Despite reduced fruit set, hexaploid × tetraploid crosses averaged almost as high in number of seedlings produced per pollinated flower as the reciprocal cross. In both types of cross, the success rate strongly depended on the particular genotypes used in crossing. The overall success rate from crosses between tetraploid and hexaploid clones was 2.32 seedlings per pollinated flower, which is high enough to allow production of large pentaploid populations for use in breeding.
A synthetic autotetraploid derived by colchicine treatment of a Vaccinium elliottii Chapm. plant (2n = 2x = 24) was used to study the effect of chromosome doubling on the ability of this noncultivated species to cross with the cultivated tetraploid highbush blueberry (V. corymbosum L.). Mean pollen germination was 28%1 for the autotetraploid plant, compared to 53% for the diploid V. elliottii plant. However, the number of seedlings obtained per flower pollinated on the tetraploid highbush cultivar O'Neal rose from 0.01 when diploid V. elliottii was the pollen source to 3.86 when pollen from the autotetraploid V. elliottii plant was used. Reciprocal crosses between diploid V. elliottii and its autotetraploid and selfs of the autotetraploid produced no seedlings. Meiotic irregularities, such as multivalent during metaphase, laggards, and unequal chromosome disjunction, were observed in the autotetraploid, but most chromosomes were associated as bivalents.
Abstract
Pollination of about 7000 flowers of tetraploid highbush blueberry clones with pollen from a wild diploid species, V. elliottii (Chapm.) Small, gave 25 phenotypically obvious hybrids. Examination of 18 of these hybrids showed that they included triploids, tetraploids, pentaploids, and aneuploids. Some hybrids appeared to be mosaics, as evidenced by chromosome-number variability in premeiotic flower buds. Most hybrids were highly vigorous. The triploids were completely female sterile and the pentaploids ranged from partially to completely female sterile when open-pollinated. Three of the tetraploids examined were highly fertile and extremely vigorous. The occurrence of 3x-4x mosaicism suggests that the 3x hybrids may have arisen from chromosome loss in 4x plants rather than from 3x zygotes. Morphological similarities between certain of the 5x hybrids and the west Florida race of the native allohexaploid species V. ashei Reade suggest V. corymbosum L.–V. elliottii allohexaploidy as one possible mode of origin for V. ashei.
Abstract
Date of 50% anthesis, date of 50% fruit ripening, length of fruit development period, fruit size, flavor, scar and color were determined for random samples of V. darrowi Camp, V. elliottii (Chapm.) Small, V. fuscatum Ait., and V. myrsinites Lam. growing in their native habitats in Alachua County, Florida. Mean berry weight ranged from 25.1 eg for V. fuscatum to 17.8 eg for V. myrsinites. V. elliottii flowered and ripened early, with only 60 days from flowering to ripening for 5 plants. V. myrsinites and V. darrowi flowered late, about 1 to 2 weeks after commercial V. ashei Reade, but ripened with V. ashei. Fruit ranged from shiny black to moderately glaucous for V. elliottii and V. darrowi but was black for V. fuscatum and V. myrsinites. Variance analysis suggested that selecting the best clone within a species is almost as important as selecting the best species in breeding most traits.
Abstract
Nineteen native blueberry (Vaccinium ashei Reade) clones selected from several areas in northern Florida and southeastern Georgia were self- and cross-pollinated in a greenhouse. Fruit set for the 19 clones averaged 15% after self-pollination and 58% after cross-pollination. Viable seeds per berry averaged four for self-pollination and 11 for cross-pollination. Average berry weight was 0.7 g for self-pollination and 1.1 g for cross-pollination, and average interval from flowering to ripening was 106 days for selfing and 92 days for crossing. Following self-pollination, pollen germinated and pollen tubes grew down the style as rapidly as after cross-pollination.
Abstract
A vigorous, compact wild rabbiteye blueberry (Vaccinium ashei Reade) plant (FL78-66) found in northeast Florida had short internodes, small leaves, and low apical dominance. S1 plants after one growing season average 31 cm tall compared to 62 cm for S1 plants from the V. ashei cultivar ‘Premier’. FL78-66 was highly fertile when crossed as male or female with V. ashei cultivars. Most F1 plants were full-statured, but some resembled FL78-66. F2 plants obtained by intercrossing short-statured F1 plants ranged from full statured to much more compact than FL78-66.
Abstract
Three diploid taxons (Vaccinium darrowi Camp, V. elliottii Chapm., and interspecific V. darrowi x V. elliottii) were treated with various colchicine concentrations and treatment durations to determine the best method for inducing autopolyploidy in in vitro blueberry cultures. Shoot-tip cuttings were the best in vitro planting material for induction of shoots with increased diameter, an indicator of polyploidy. Tetraploids were produced at colchicine concentrations from 0% to 0.20%. The best treatment combinations were genotype-dependent.