Search Results

You are looking at 1 - 10 of 36 items for

  • Author or Editor: Paul Lyrene x
  • All content x
Clear All Modify Search
Free access

Paul Lyrene

Diploid blueberry (Vaccinium section Cyanococcus) was pollinated in a greenhouse in 1981 with pollen from sparkleberry (V. arboreum, Section Batodendron). Cyanococcus parents included V. darrowi, diploid V. corymbosum, and various intra-sectional diploid hybrids. Forty one vigorous seedlings showing characteristics of both sections were selected from a field nursery when 2 ½ years old. Some of these plants flowered heavily in subsequent years, and several were more than 3 m tall by 1990. Although the F1 hybrids had very low fertility, some open-pollinated progeny were obtained. Some of these were vigorous, fruitful when open-pollinated in the field, and intermediate between V. arboreum and Cyanococcus in many features. Six of the best progeny from open-pollination of the F1's were used in greenhouse crosses. Some branches were self-pollinated and some were pollinated with pollen from tetraploid V. corymbosum -based cultivars. Two of the 3 selfed plants had a high percent fruit set (277 fruit from 441 flowers). Four of the six plants pollinated with pollen from tetraploid V. corymbosum cultivars had high percent fruit set (452 fruit from 793 flowers). Flowers of the open-pollinated progeny of the F1 hybrids were much larger than those of the F1 `s. This, along with the fruitfulness after 4× pollination, suggests that at least some of the open-pollinated progeny are tetraploid. These hybrids give hope that sparkleberry genes can be used to improve highbush cultivars.

Free access

Paul Lyrene

Free access

Paul Lyrene

The best time to harvest fresh blueberries in Florida is 1 April to 15 May. Weather during this period is normally favorable for harvest: low rainfall, low humidity, warm, sunny days, and cool nights, and supplies of fresh blueberries from other producing areas are low. To ripen high-quality blueberries in April, the plants must flower in February and must have a full canopy of leaves to support the developing crop in March and April. Observations of thousands of blueberry seedlings and selections over the past 25 years in Florida have indicated that blooming and leafing time are affected by the chilling requirement and heat requirement of the variety and also by environmental factors. Factors that increase plant vigor (high soil fertility, ample moisture, and young plants) cause the plants to flower earlier in the spring. Flower buds that do not open by 15 Mar. in north Florida frequently abort. The timing and extent of this physiological bud abortion varies with cultivar. Some southern highbush cultivars leaf before they flower. Others flower before they leaf. The ideal blueberry variety for north Florida would have a very low chill requirement, a high heat requirement to prevent January flowering, and a short flowering-to-ripening interval.

Free access

Description of Cultivars: Science or Advertising

A Reply to Werner J. Lipton's Essay in the April 1988 ASHS Newsletter

Paul Lyrene

Free access

Paul Lyrene

Cultivated blueberries (Vaccinium section Cyanococcus species, including lowbush, highbush, and rabbiteye) normally produce flower buds at the end of the growing season; these remain dormant during the winter and give rise to flowers the following spring. However, rabbiteye and low-chill highbush cultivars that are maintained in a state of vigorous growth throughout the winter in an unheated greenhouse in Gainesville in north Florida flower and produce fruit continuously on new growth throughout December, January, and February. The regimen of cool (but not freezing) nights and short, warm days permits the plants to continue growth throughout the winter and results in rapid conversion of newly-formed axillary buds into flower buds. These do not become dormant, but sprout to produce flowers and fruit almost as quickly as they are formed. Extending the photoperiod or raising night temperatures inhibits primocane flowering by allowing the axillary buds to remain vegetative. Primocane flowering, which occurs naturally in highbush blueberry production fields south of lat. 28°N in Florida and at lat. 30°S in eastern Australia, can contribute to an extended harvest season (4 to 8 months per year) from a single cultivar.

Free access

Paul M. Lyrene

‘Emerald’ is a low-chill tetraploid southern highbush blueberry hybrid that is well adapted to northeast and central Florida and to other areas receiving similar winter chilling (100 to 400 h below 7 °C). Emerald produces a vigorous bush with stout, semierect canes. It has medium to good survival in the field in north Florida. In northeast Florida, ‘Emerald’ flowers from mid-January to mid-February and ripens from mid-April to mid-May. ‘Emerald’ is capable of producing high yields of berries that are large, firm, and medium-dark in color with a small, dry picking scar and good flavor.

Full access

Paul M. Lyrene

Nine F1 hybrids produced by crossing seven tetraploid highbush blueberry cultivars with three tetraploid Vaccinium stamineum genotypes were backcrossed to an array of highbush blueberry cultivars to produce 2500 Backcross1 (BC1) seedlings. Thirty of the most vigorous BC1 plants were intercrossed in a greenhouse. Fertility of the BC1 plants was studied by examining their pollen at 250× and by determining the number of well-developed seeds per pollinated flower after the crosses. Percent well-formed microspores averaged 62.7% for BC1 plants compared with 30.9% for their F1 hybrid parents. Fruit set percentage was high from the BC1 intercrosses, with an average of 9.29 plump seeds per pollinated flower. The 2500 BC1 seedlings in the field were highly variable in vigor, but fewer than 10% were as vigorous as the median vigor of highbush × highbush seedlings. BC1 plants in the field averaged ≈1 month later ripening than highbush × highbush seedlings and berries averaged slightly smaller. Berry clusters were very loose compared with those of highbush. Berry flavor was highly variable from plant to plant, but the berries averaged less sweet and lower in acid than highbush berries. New flavor components not found in highbush seedlings were found in only a few BC1 seedlings. Fresh berries from BC1 plants made bright red juice when crushed in water, whereas berries from most highbush cultivars produced brown to yellow juice/water mixes. Although berry quality in the BC1 population averaged lower than in highbush seedlings, some plants had berry quality as high as typical cultivars. Because V. stamineum is highly drought-tolerant, cultivars bred using V. stamineum introgression could have improved upland adaptation.

Free access

Paul M. Lyrene

Several hundred hybrid seedlings were produced by pollinating flowers of tetraploid highbush blueberry cultivars with pollen from 13 plants of Vaccinium stamineum that were selected as tetraploids following colchicine treatment. The hybrids were intermediate between the parents in many characteristics. They were less vigorous than the parents, but 46 plants flowered when 1.3 years old from seed. The F1 hybrids produced pollen abundantly, but only 30% of the microspores appeared potentially viable when viewed at 250X. F1 flowers that were pollinated with pollen from either parent taxon or with pollen from a different F1 hybrid produced thousands of well-developed seeds. The F1 hybrids were less successful when used as male parents in backcrosses to highbush, but 4790 well-developed seeds were obtained by pollinating 3250 highbush flowers. Flowers on F1 plants had long peduncles and pedicels, giving an open raceme. The flowers were open in the bud and had anther awns, two characteristics from V. stamineum. Berries on the F1 plants had black skins, and the ripe berries of 11 F1 plants had red to purple pulp like their V. stamineum parent. Berries on the hybrids were juicy. They had little or no bitterness typical of V. stamineum, and most had a pleasing balance of sugar and acid.

Free access

Paul M. Lyrene

Breeding to adapt temperate-zone fruit to subtropical production areas has been a formidable objective because so many different characteristics have to be changed, most of which are controlled by many genes. Recurrent selection is the only breeding method that can accomplish the required wholesale reorganization of the physiology of the plant. The principles of recurrent selection, developed and tested using short-generation organisms like fruit flies, rats, and maize, have been applied to the development of low-chill highbush blueberry (V. corymbosum L.) and peach [Prunus persica (L.) Batsch.] cultivars for northern and central Florida. These principles include using many parents per generation of crosses, minimizing the time between cycles of selection, and selecting simultaneously for all heritable traits that are important in the final product, with traits of highest economic importance and highest heritability being given the highest weight in selecting parents. Many characteristics changed during the breeding of low-latitude peach and highbush blueberry cultivars, including chill requirement, photoperiod response, resistance to various disease and insect pests, fruit chemistry, and growth patterns during a long growing season.