During the past 10 years, the Florida strawberry growers, through the Florida Strawberry Growers Association, have made a serious commitment to fund university research on strawberries. They have purchased equipment and donated monies for facilities at Dover. They have also helped support a new faculty position in breeding and genetics. During this same period, the University of Florida has made an equally strong commitment to support strawberry research and extension. These commitments are beginning to pay significant dividends for industry and the University. Cultural and pest management information has been generated that is saving the industy money, and the breeding program is developing new cultivars that will keep the industry competitive in the marketplace. The University has benefitted through the acquisition of new facilities, equipment, and faculty and graduate student support.
Craig K. Chandler, T. E. Crocker, and E. E. Albregts
Joseph H. Connell and Richard L. Snyder
Almond (Prunus dulcis Mill.) cultivars vary in tolerance to cold with flowers at pink bud more tolerant than at full bloom or than small nuts. Branch samples 60 cm long with 30-100 blossoms or nuts were cut, sprayed with water, and artifically frozen. Subsamples were removed after exposure to 4 to 6 successively lower temperatures for 30 minutes. After 48 hours of ambient temperatures, flowers or small nuts were sectioned and examined for visual evidence of injury. Of the early cultivars, `Peerless', is most sensitive at full bloom and `Sonora' is most hardy. `Sonora' is especially hardy at pink bud. `NePlus Ultra' is intermediate. Of the mid-blooming cultivars, `Carmel' is most sensitive to cold while `Nonpareil' is most tolerant. `Price' is intermediate. The late blooming cultivar, 'Mission' is most sensitive while 'Padre' and 'Butte' appear similar. This study compared several popular new cultivars to older industry standards.
Djamila Rekika, Shahrokh Khanizadeh, Martine Deschênes, Audrey Levasseur, Marie Thérèse Charles, Rong Tsao, and Raymond Yang
Eighteen strawberry genotypes were evaluated for their phenolic content and antioxidant capacity using several methods. High antioxidant capacity was found for `Harmonie', `Saint-Jean d'Orléans', and `Saint-Laurent d'Orléans', which were reported to have better shelf life than `Kent'. `Harmonie', `Saint-Jean d'Orléans', `Orléans', and some advanced selections had higher hydroxycinnamic acids, benzoic acids, and flavonols than `Kent'. The significant variation in antioxidant capacity and total phenolic compounds clearly shows the potential value of certain new cultivars and advanced lines as parents in a breeding program. The future plan is to examine individual antioxidant and their role in disease resistance and extension of shelf life and to use selected genotypes as parents to developed new lines.
Shahrokh Khanizadeh, Yvon Groleau, Audrey Levasseur, Odile Carisse, Djamila Rekika, Jennifer DeEll, Jean-Pierre Privé, Inteaz Alli, and Henk Kemp
`SuperMac' (Malus ×domestica Borkh) is being released as a replacement for `Spartan', which is presently being grown in Eastern Canada for its excellent shelf life. However, it is susceptibility to scab [Venturia inaequalis (Cke) Wint.], the most common apple disease. This new cultivar produces larger fruit than `Spartan' and is resistant to apple scab. It is very attractive (Fig. 1), has a pleasant taste and an excellent shelf life, and keeps very well and longer compared with the `Spartan'. `SuperMac' is a `McIntosh'-type apple. The tree is hardy to –30 °C, and the fruit and leaves are resistant to the common races of apple scab resulting from the presence of the V f gene derived from Malus floribunda 821.
Antonia Y. Tetteh, Todd C. Wehner, and Angela R. Davis
Information on the mode of inheritance of powdery mildew resistance in watermelon is important for designing a breeding strategy for the development of new cultivars. Resistance in the watermelon accession PI 270545 was investigated by generation means analysis by crossing it with susceptible PI 267677. The analyses showed involvement of two genes, a recessive resistance gene, pmr-1, and a dominant gene for moderate resistance, Pmr-2. Resistance to powdery mildew in the leaf had a large dominance effect and a heritability of 71%. The additive-dominance model was inadequate in explaining variation in leaf resistance as revealed by the joint scaling test. However, nonallelic interactions could not be detected by the nonweighted six-parameter scaling test. For stem resistance, the additive-dominance model was adequate, and inheritance was controlled mainly by additive effects. A high narrow-sense heritability of 79% suggested that selection for stem resistance in early generations would be effective.
Stanley J. Kays, Jason Hatch, and Dong Sik Yang
Selection emphasis on cyme size and flower color of Heliotropium arborescens L. has led to cultivars with diminished floral fragrance. As a preliminary inquiry into the fragrance chemistry of the species, we identified 41 volatile compounds emanating from the flowers of 'Marine' via isolation (Tenax trapping) and gas chromatography–mass spectrometry. The majority of the volatile compounds emanating from the flowers were terpenes (camphene, p-cymene, δ-3-carene, α-humulene, δ-1-limonene, linalool, (E)-β-ocimene, α-pinene, and β-thujone), benzenoids of which benzaldehyde was the most abundant, aldehydes (decanal, heptanal, nonanal and octanal), and hydrocarbons (decane, heneicosane, heptadecane, hexadecane, nonadecane, nonane, octadecane, tetradecane, tridecane and undecane) along with a cross-section of other compounds. Subsequent identification and quantification of critical ordorants will facilitate selecting new cultivars with quantitative and qualitative improvements in fragrance.
Jianhua Li, Michael S. Dosmann, Peter Del Tredici, and Susyn Andrews
Sequences of the internal transcribed spacers (ITS) of nuclear ribosomal DNA were used to examine genetic divergence of the two species of katsura [Cercidiphyllum japonicum Sieb. & Zucc. and Cercidiphyllum magnificum (Nakai) Nakai] and four clones of weeping katsura (`Amazing Grace', `Tidal Wave', `Pendulum', and `Morioka Weeping'), and to characterize the affinity of these weeping katsura to both species. Our results indicate that C. japonicum and C. magnificum are genetically distinct, supporting the recognition of them as separate species. Based on our DNA sequence data and morphological evidence, all weeping selections are phylogenetically derived from C. japonicum, not C. magnificum; nor are they of a hybrid origin between C. japonicum and C. magnificum. We propose the new cultivar-group Cercidiphyllum japonicum Weeping Group to include all katsura clones of weeping or pendulous habit, and recognize the cultivar epithet `Morioka Weeping' and its application to the excurrent and upright clone obtained from Japan and distributed in North America by the Arnold Arboretum.
John R. Clark, James N. Moore, and Penelope Perkins-Veazie
`White Rock' and `White County' fresh market peaches (Prunus persica (L.) Batsch) were released in 2004 by the University of Arkansas Agricultural Experiment Station. These cultivars join `White River' as recent products of the peach breeding program which is based at the University of Arkansas Fruit Substation, Clarksville. Both cultivars are sub- or low-acid types and have white flesh. `White Rock' ripens at on average 25 June, and is very firm at maturity. Average fruit weight was 142 g with 12% soluble solids and light white peach flavor. `White County' ripens on average 14 July. It is large fruited with average weight of 258 g and maintains firmness until full maturity. The fruits are freestone with an excellent white peach flavor. Both cultivars show good bacterial spot resistance although occasional lesions are seen on leaves. These new cultivars offer additional white peach cultivar choices for the mid-South and other areas of similar climate.
Duane W. Greene and Wesley R. Autio
There is a general increase in interest in planting new apple cultivars. The loss of daminozide has provided an additional stimulus for growers in New England to find an alternative to McIntosh. Promising new apple cultivars have been identified from around the world and from breeding programs in Arkansas, British Columbia, New York, New Jersey and the PRI Program. Trees were propagated and planted in a cultivar evaluation block at the University of Massachusetts Horticultural Research Center. In 1992 we evaluated over 80 new cultivars. Fruit assessment consisted of laboratory analysis and visual and sensory evaluation. All cultivar were given an overall rating, and several were identified as being worthy of further evaluation. These apple cultivars include: Arlet, BC 9P 14-32, BC 8M 15-10, BC 17-30, Ginger Gold, Honeycrisp, Kinsei, NJ 55, NY 75414-1, and Sansa.
R.L. Fery and P.D. Dukes
The USDA has released a new cream-type southernpea [Vigna unguiculata (L.) Walp.] cultivar that is well adapted for productionthroughout the southern United States. The new cultivar, named `Tender Cream', is the product of a backcross breeding procedure to transfer the dominant Rk gene for root-knot nematode resistance from `Floricream' into `Carolina Cream'. `Tender Cream' is resistant to cowpea curculio, root-knot nematodes, southern bean mosaic virus, cercospora leaf spot, southern blight, rust, and powdery mildew. `Tender Cream' outyielded the cream control in the 1992, 1993, and 1994 Regional Southernpea Cooperative Trials by 5.4%, 11.0%, and 18.8%, respectively. It outyielded its root-knot-nematode-susceptible `Carolina Cream' isoline by 22.3% in a replicated 1994 test conducted in a field infested with a natural population of the southern root-knot nematode. Canned samples of fresh `Tender Cream' peas scored well during 3 years of testing at the Univ. of Arkansas.