`African Beauty', a new ornamental camphor basil cultivar, was developed through three cycles of selfing and selection from USDA accession PI 500942, originally collected in Zambia, Africa. `African Beauty' was field-evaluated and compared with PI 500942 (the original population), PI 500954 (another accession from Zambia), a camphor cultivar from Companion Plants, and three other related lines in 1997 and 1998. Most commercial camphor basils are tall (50 to 60 cm), late-flowering, and unattractive. Our goal was to develop a new cultivar that had a short stature (≈40 cm), an early flowering, and an attractive appearance. The outcome was `African Beauty', which has the following characteristics: plant height: 30 to 35 cm, plant spread: 50 to 55 cm, leaf length: 6.3 to 6.7 cm, days to flower: 76 days, inflorescence length: 25 cm, essential oil yield: 3 mL/100 g dw. The essential oil of `African Beauty' is also highly aromatic, with 72% camphor, 12% camphene, and 9% limonene. The plant is a fast-growing, semicompact aromatic plant that produces small leaves and large quantities of long and slender inflorescences that, when fully developed, curve at the tip like the tail of a cat. Blooming usually lasts from 20 to 25 days, when the plant looks most beautiful. `African Beauty' is an attractive ornamental that would be excellent as a garden border plant, or as an indoor potted plant.
Mario R. Morales and James E. Simon
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.
Christopher Gunter, David Francis, and Alba Clivati McIntyre
Yellow shoulder disorder (YSD) is a physiological disorder of processing tomato that affects both the appearance and nutritional quality of the fruit. This disorder reduces the suitability of fruit intended for the whole-peeled and diced product markets. The YSD involves an interaction between plant genotype and the environment. A number of soil factors have been related to the incidence of YSD, including organic matter, phosphorous, K/Mg ratios, and soil K. Varieties of tomatoes differ in their susceptibility to color disorders, thus variety selection offers growers one strategy to manage this color disorder. The use of supplemental K application at a time when plants are blooming and actively growing offers a second strategy for management of YSD. To this end, a field study was conducted at the Southwest Purdue Agricultural Program in southwestern Indiana to study the effects of different sources of K on the color and quality of tomato fruit. Potassium chloride, potassium nitrate, and potassium sulfate were applied at first flowering in a solid, broadcast application. Appropriate controls were used to balance the nutrients supplied in addition to K. Supplemental K, regardless of source, improved fruit hue, though the trend was not always statistically significant between treatments. Variety specific effects were observed. This is a complex disorder and its management will entail minimizing risk of incidence through careful selection of variety and field location.
David A. Bender, Roland E. Roberts, and Frank J. Dainello
Watermelon is grown under a range of moisture regimes from rainfed to heavily irrigated, but water requirement patterns are not well documented. Drip irrigation and plastic mulch provide the opportunity to control water applications to optimize yield and quality. Water applied through subsurface drip irrigation was measured in two watermelon trials in 1998 (25 seeded and 20 seedless cultivars) and 1999 (26 seeded and 14 seedless cultivars) at Lubbock, Texas. Melons were transplanted in plastic-covered raised beds 13.6 m long spaced 2 m apart. Irrigation was applied when morning soil moisture tension measured by tensiometers exceeded 20 kPa. Watermelon yields ranged from 50 to 100 t·ha-1 with excellent quality. Weekly water use averaged 14 mm during the first 3 weeks of establishment then increased to 28 mm during the next 3 weeks as plants were running and blooming. During the 5-week fruit-enlargement period, water uptake averaged 57 mm, then decreased as full fruit size was attained. Similar uptake patterns in both years suggest that meaningful crop coefficients for scheduling watermelon irrigation could be based on phenological growth stages.
Jianying Peng and Peter Hirst
Buds were sampled from nonflowering spurs on 1-year-old wood of 10 apple cultivars during the 2004 growing season and dissected to determine floral commitment and morphogenesis. Dissected buds were classified into five stages based on floral bud morphogenesis. The 10 cultivars differed in their patterns of floral commitment and morphogenesis. At the end of the growing season, the proportion of floral buds was 30% to 100% depending on cultivar. The probability of observing doming, indicating floral commitment, was from 5% to 50% depending on cultivar, with `NJ90' (50%), `Zestar' (30%), and `CQR10T17' (30%) rated among the highest. The lowest probability (5%) was with `Ambrosia', `Pinova', and `Silken'. The time of a peak of floral commitment was earliest in `Delblush' and `CQR10T17' and latest in `Sundance'™ and `Pinova'. Most cultivars exhibited a single peak of floral commitment, except for `Pink Lady' in which two peaks were present. The duration of the process of flower initiation was from 20 to 43 days depending on cultivar. The timing of floral commitment and morphogenesis was not related either to blooming date, or to fruit harvest time of the cultivar.
Gary J. Keever and J. Raymond Kessler Jr.
In previous studies, night-interrupted lighting (NIL) promoted earlier flowering of summer-blooming herbaceous perennials grown under outdoor nursery conditions in the southeastern U.S. However, NIL promoted excessive plant height, thus reducing product quality. Our objective was to control plant height of Coreopsis grandiflora `Early Sunrise' (ES) and Rudbeckia fulgida `Goldsturm' (RG) grown under NIL with plant growth retardants (PGR) without offsetting earlier flowering promoted by NIL. Treatments under NIL were three rates of daminozide, daminozide plus chloromequat, flurprimidol, uniconazole, and NIL and natural controls. Plant height was reduced 3% to 38% in ES and 8% to 31% in RG and time to visible bud was unchanged by all PGR treatments compared to the NIL control. Time to visible bud was unchanged in RG by all PGR treatments and flurprimidol in ES, but the remaining PGR treatments increased time to visible bud compared to the NIL control in ES. Only ES plants treated with daminozide and daminozide plus chloromequat at the two highest rates and all rates of uniconazole were similar in height to the natural control. RG plant heights with the two highest rates of flurprimidol and uniconazole and the highest rate of daminozide plus chloromequat were less than the natural control; heights of plants in the remaining PGR treatments were similar to the natural control. Quality rating was unchanged in RG but was increased in ES by all PGR treatments compared to the NIL control.
Ioannis C. Porlingis and Demetrios G. Voyiatzis
Anthesis of an important staminate pistachio (Pistacia vera L.) cultivar (B) in Greece was delayed by foliar paclobutrazol (PBZ) sprays applied in June or July the previous season. A September spray was ineffective. The amount of delay depended on dose (50 to 1000 mg PBZ/liter applied to incipient runoff). Using the same total amount of chemical, one spray was as effective as two sprays 1 month apart. There were no effects on inflorescence fresh weight, pollen production, and pollen germination. Stem elongation was inhibited strongly, but the number of nodes and flower buds per shoot was reduced only slightly. In Expt. 2, two other staminate cultivars (A and C) responded similarly to cultivar B. Treatment effects appeared only during the treatment year, whereas a soil drench was effective for 2 years. PBZ may be able to synchronize the blooming of staminate and distillate pistachio cultivars and result in good fruit set without artificial pollination. Chemical name used: B[(4-chlorophenyl)methyl] -α-(1,1 dimethylethyl)-l H -1,2,4-triazole-l-ethanol (paclobutrazol).
James R. Ballington and Susan D. Rooks
Three rabbiteye blueberry selections, NC 1550, NC 1877, and NC 2305, will be released by the North Carolina Agricultural Research Service in Spring 1997. All three selections are self-fruitful, with fruit as large or larger than Tifblue, with good picking scars, aromatic flavor, and resistance to fruit cracking. NC 1877 is early-blooming and ripens a few days later than Premier, with similar color, firmness, and quality. Plants of NC 1877 are semi-upright and of only moderate vigor. Both NC 1877 and NC 1550 are resistant to the sharpnosed leafhopper which transmits blueberry stunt. NC 1550 blooms with or slightly later than Tifblue and is outstanding for consistent productivity, particularly on spring frost—prone sites. It ripens in early midseason to midseason, usually a few days ahead of Tifblue. Stemming was a problem in one year on overcropped plants. NC 1550 and NC 2305 have average to above color, and fruit firmness equal to Tifblue. NC 2305 blooms and ripens with Tifblue in most years. Fruit quality is at least equal to Premier and it fruits primarily on the tips of the branches. The names of these selections are Ira' (NC 1550), 'Montgomery' (NC 1877), and 'Yadkin' (NC 2305).
Arlen D. Draper
The USDA blueberry breeding program was initiated in 1910 by Dr. F.V. Coville and has been continuous since that time. Plant breeders Drs. G.M. Darrow, D.H. Scott, J.N. Moore, and A.D. Draper have worked with SAES and private growers to develop the majority of cultivars presently grown for commercial production. In the South, major cooperators with the USDA include SAES in Arkansas, North Carolina, Georgia, and Texas. Recently the USDA Station at Poplarville MS, has been instrumental in blueberry cultivar development for the South. Rabbiteye blueberry cultivars make up the majority of blueberry acreage grown in the region. A new type of blueberry, the southern highbush (SHB), has been developed by interspecific hybridization with various Vaccinium species. Late-blooming SHB cultivars have been developed that offer better protection from spring frosts and ripen earlier than the earliest rabbiteye blueberry. Genes required to meet future needs reside within native Vaccinium species. Progress has been made in plant adaptation, disease resistance, fruit quality, and season of ripening. There remains a need for greater plant vigor, insect resistance, and consistent production.
The variability of species under local ecosystems, particularly in response to temperatures during endodormancy, permits adaptation of temperate fruit trees to subtropical climates. Information about the behavior of endodormant fruit trees and seeds is based on a narrow genetic base from higher latitudes. This work was conducted to generate information about responses of endodormant seeds from several subtropical peach (Prunus persica L.) genotypes, as a basis for breeding and selection in these regions. Samples of peach seeds were collected from genotypes originating at a range of altitudes in tropical-subtropical regions to evaluate their responses to different temperatures and lengths of stratification periods. When seeds were stratified at 7 °C, some genotypes with very low-chilling requirement registered a high percent germination in <40 days, and all accessions studied reached 95% germination before day 80. When seeds were stratified at warmer temperatures (10 and 14 °C), germination started earlier and was high at 10 °C for most accessions. Although seeds of some late-blooming accessions germinated earlier at 10 or 14 °C than at 7 °C, percent germination was lower and time-response curves were flatter. This contrasts with previous reports on genotypes with high-chilling requirement, where no germination was registered at 14 °C. These observations provide a background for screening seedlings for adaptation to local conditions, and suggest that endodormancy models should be based on information generated from local genotypes when applied in subtropical regions.