Search Results

You are looking at 1 - 10 of 43 items for

  • Author or Editor: P.M. Lyrene x
  • Refine by Access: All x
Clear All Modify Search
Free access

P.M. Lyrene

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.

Open access

P. M. Lyrene

Abstract

Seventeen rabbiteye blueberry clones observed for 4 years at Gainesville, Fla., showed much year-to-year and clone-to-clone variation in flowering and ripening dates. If, however, year effects were removed by expressing flowering and ripening dates as deviations from year means, the sequence in which the 17 clones flowered and ripened was highly repeatable, with little clone × year interaction.

Open access

P. M. Lyrene

Abstract

Ten colonies of Vaccinium darrowi Camp were sampled at each of 9 sites in the Florida panhandle and 6 sites in and around the Ocala National Forest in the central Florida peninsula. The colonies averaged 53 cm tall in the panhandle, with leaves 9.8 mm long and 4.1 mm wide. By contrast, colonies in the peninsula averaged 136 cm tall—well outside the range described for the species—with leaves 12.7 mm long and 5.7 mm wide. The species was diploid and entirely evergreen in both regions. In the central Florida peninsula, natural hybrids between V. darrowi and a 3-m tall, deciduous, diploid race of highbush blueberry (V. corymbosum L.) are common where streams and lakes border the dry scrub habitat of V. darrowi. The robust form of V. darrowi in the Florida peninsula may have evolved from the petite form in the panhandle as a result of introgression from the highbush coupled with selection for characteristics that enhance survival on the deep, xeric sands of the peninsula. V. darrowi from the central peninsula has characteristics that make it valuable in breeding blueberry cultivars.

Open access

P.M. Lyrene

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.

Open access

P.M. Lyrene

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.

Open access

P. M. Lyrene

Abstract

Removing the terminal 10 cm from shoots of rabbiteye blueberry (Vaccinium ashei Reade) plants on 27 Oct. induced flower buds below the cut, even though no new vegetative growth occurred. The average number of new flower buds formed per twig ranged from 1.3 for ‘Delite’ to 6.1 for ‘Climax’ with an average of 3.0 for the clones tested. Unpruned twigs of the same clones averaged only 0.5 new flower buds on comparable twig sections. Tying unpruned twigs to a horizontal position during the period of flower bud formation had no effect on number or location of flower buds on the twigs.

Open access

P. M. Lyrene

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.

Open access

P. M. Lyrene

Abstract

Fifty-four seedlings of Vactinium ashei Reade, selected for large fruit and high fruit quality from 3000 seedlings of 8 crosses, were scored for dates of 50% anthesis and 50% fruit-ripening in 1981 and 1982. The earliest-ripening selection was 7 days earlier than the earliest cultivar in 1981 and 15 days earlier in 1982. Repeatability (seedling correlation between years, r = .84) was high for ripening date but somewhat lower for flowering date (r = .61) and flowering-to-ripening interval (r = .62). Most of the variation in ripening dates and in the flowering-to-ripening interval was genetic, but variation in flowering dates was due more to year effects than to genetic effects.

Open access

P. M. Lyrene

Abstract

Eighteen cultivars of the Chinese jujube (Zizyphus jujuba Mill.) grown in Florida comprised 2 flowering types based on the time of day when the flowers open. Flowers on 10 cultivars open each day between 0700 and 1000 hr and on the other 8 between 1400 and 1700 hr. Despite ample opportunity for cross-pollination and intense activity by pollinating insects, some cultivars set little or no fruit. Cultivars that fruit heavily and reliably are parthenocarpic. Supplemental light in the fall prolongs flowering and fruiting and could substantially increase yields.

Open access

P. M. Lyrene

Abstract

Multiple shoot formation from shoot tips taken from juvenile rabbiteye blueberry (Vaccinium ashei Reade) seedlings was induced on Knops medium with agar, casein hydrolysate, and N6-(∆2-isopenteny1)-adenine (2iP) at 15 mg/liter. These shoots could be easily subcultured and rooted readily when cut off and inserted into a peat-perlite mixture under mist in the greenhouse. Nonjuvenile shoot tips from rabbiteye cultivars were difficult to establish in cultures. Successful establishment of some clones occurred by formation of fine, filamentous shoots which were as amenable to subculture as juvenile shoots. A 50-fold multiplication rate every 4 months was obtained with some clones.