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.
Stanley J. Kays, Jason Hatch, and Dong Sik Yang
F. Kappel, P. Toivonen, D.-L. McKenzie, and S. Stan
Several sweet cherry (Prunus avium L.) cultivars were stored in air or modified-atmosphere packages (MAP) at 1 °C for 2 or 4 weeks, respectively. The new cultivars included `Santina', `Sumpaca Celeste', `Sumnue Cristalina', `Sumste Samba', `Sandra Rose', `Sumleta Sonata', and `Skeena', and the standards were `Lapins', `Sweetheart', and `Bing'. Fruit were rated for defects (stem browning, stem shrivel and fruit surface pitting), and fruit quality at harvest and after storage. Weight loss during storage was influenced by year, storage treatment, and cultivar. Stem shrivel, stem browning, and fruit surface pitting varied among cultivars and years. Generally, fruit stored in MAP had higher fruit firmness than at harvest or when stored in air. The respiration rate of fruit was lower in later than in earlier maturing cultivars, but respiration rate at harvest was not related to any of the quality measurements taken after storage.
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.
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.
Creighton L. Gupton and Barbara J. Smith
Eight cultivars, including five recent releases, five selections from the Florida AES, and 16 selections from the Georgia AES were planted in the muscadine germplasm working collection at McNeil, Miss., in 1992. All cultivars and one replication of the selections were evaluated in 1997. None of the new cultivars yielded as much as `Fry', the standard fresh fruit cultivar. The percent dry picking scar of `Dixie' and `Fry' was low. `Tara', `Polyanna', and `Fry' produced the largest berries. Percent soluble solids was lowest in `Fry', `Nesbitt', and `Alachua' but highest in `Dixie' berries. `Fry', `Alachua', and `Polyanna' had the lowest and the other cultivars did not differ in number of seed per berry. One selection, 33-1-4, appeared to have the qualities of a potential cultivar. Incidence and severity of berry rots were generally low.
Richard L. Fery
The USDA has released a new, pinkeye-type southernpea cultivar that is homozygous for the gc gene conditioning the green cotyledon trait. The new cultivar, `Charleston Greenpack', can be harvested at the near-dry stage of pod maturity without loss of the pea's fresh green color. `Charleston Greenpack' originated as a bulk of an F8 [`Kiawah' × (`Kiawah' × `Bettergreen')] population grown in 1994. Except for the green seed color, a tendency for a slightly greener foliage, and a slightly smaller pea size, the phenotype of `Charleston Greenpack' is quite similar to those of `Coronet' and `Pinkeye Purple Hull-BVR'. The results of replicated field tests indicate that `Charleston Greenpack' yields are comparable to those of `Coronet' and `Pinkeye Purple Hull-BVR'. Results of raw product evaluations conducted at a commercial freezing facility indicate that `Charleston Greenpack' produces an excellent processed product. `Charleston Greenpack' has excellent field resistance to blackeye cowpea mosaic virus, the major pathogen of southernpea in the United States.
James N. Moore
Blackberries have long been a popular fruit in the southern U.S., and they are widely grown there, with excellent potential for expanded production. Raspberries are also well-liked, but not widely grown, due to lack of adapted cultivars. Great progress has been made, particularly in the past four decades, in improving blackberry cultivars for the South, but little effort has been given to raspberry improvement. Germplasm exists within Rubus to provide great advances in conventional cultivar improvement in both subgenera and for creating new types of fruits through interspecific hybridization. Germplasm and breeding strategies will be discussed that would result in new cultivars to serve as the foundation on which to build much expanded blackberry and raspberry industries in the southern United States.
Kimberly J Walters, George L. Hosfield, and James D. Kelly
Ninety-eight percent of the navy beans (Phaseolus vulgaris) grown in the US are processed. Thus, new cultivars considered for release must meet industry standards. Canning quality behaves as a classical QTL which precludes its selection and evaluation in early generations. Such delays add a measure of inefficiency to a breeding program. Indirect selection for canning quality using molecular markers could increase efficiency. RAPD markers are more useful than RFLP's, in Phaseolus, due to a simpler protocol and a higher level of polymorphism within genetically related cultivars. Three populations of RIL's, derived from crosses between cultivars with standard and sub-standard canning quality, were screened to identify markers associated with canning quality. Material for evaluation was grown at two locations, in three replications and processed, in the Food Science Processing Lab, following industry standards. Quality traits measured were: processed texture, color and appearance. Associations of putative markers with canning quality were identified using ANOVA and Mapmaker programs
Craig K. Chandler, T. E. Crocker, and E. E. Albregts
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.
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.