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  • Journal of the American Society for Horticultural Science x
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Abstract

The spatial distribution of nematodes in the soil of nine California vineyards was surveyed in summer and winter months. Soil samples were taken in the vine row and between rows at 15 cm depth intervals. There were no measurable seasonal changes in nematode distribution. Variation in the distribution of genera amongst vineyards was related to soil physical conditions and vineyard cultural practices. In general, highest concentrations of Meloidogyne spp. and Xiphinema spp. were in the upper 60 cm of soil in the vine row, whereas Tylenchulus semipenetrans was more deeply and uniformly distributed throughout the root zone.

Open Access

Abstract

A survey for dead spur was made by rating 8600 ‘Delicious’ apple trees (Malus domestica Borkh.) on seedling rootstock in 3 of the 4 major apple-growing areas of Washington. Only ‘Earlistripe Delicious’ was found to be appreciably affected, and no difference in incidence of dead spur was observed among the areas.‘Oregon Spur Delicious’ and ‘Earlistripe Delicious’ were rated on 5 rootstocks and no rootstock effect was detected. Dead spur symptoms on trees of other strains or cultivars and on pollenizer limbs grafted into ‘Earlistripe Delicious’ affected by dead spur suggest the disorder is transmissible. In addition, an association was noticed between cultivars with long leggy-type growth and the occurrence of dead spur.

Open Access
Authors: and

Field surveys were conducted on cultivated strawberries (Fragaria ×ananassa Duch.) to determine the time of flower initiation and its relation to maximum and minimum temperatures and daylength. Stereomicroscopy and scanning electron microscopy (SEM) were compared. Flower initiation in `Torrey' strawberry was more dependent on minimum temperature than on daylength or maximum temperature. Flower initiation in the day-neutral `Aptos' occurred regardless of daylength or temperature during sampling. For the study of flower initiation and inflorescence development, SEM gave more detail than stereomicroscopy.

Free access

Retail florists' performance ratings of services provided by wholesale growers, wholesale florists, and grower-shippers/brokers were factor-analyzed to yield a hierarchical classification of customer service in floral distribution. Nine customer service factors were identified and three major independent classes of customer service were defined, including 1) physical distribution, 2) marketing, and 3) product quality services. Florists rated the performance of suppliers' physical distribution services higher than marketing and product quality services. Florists' perception of physical distribution and product quality services did not vary across type of supplier, but for marketing services, florists rated wholesale growers higher in performance than wholesale florists. The hierarchical classification of customer service and service performance profiles provide the floral industry with relevant market information for the successful development and effective implementation of customer service programs.

Free access

For the past century, daylily (Hemerocallis) hybridization focused almost exclusively on enhancing the diversity of flower forms, colors, and color patterns. This focus on the visual characteristics of daylilies resulted in the development of thousands of hybrids that come in a fantastic array of colors and color patterns. However, these modern daylilies exhibit little to none of the floral fragrance possessed by some of the daylily progenitor species. Because little work has been done on daylily floral volatiles, the objective of this research was to evaluate the floral volatile profiles of a variety of daylily species and hybrids and assess the state of fragrance among modern hybrids. Using a field collection system and gas chromatography–mass spectrometry (GS-MS), this study evaluated the fragrance profiles of 147 daylily genotypes. Eighteen volatile organic compounds, primarily terpenoids, were identified and their variations among the genotypes were investigated. Results suggest that fragrance could be a trait pursued in a breeding program to enhance the sensory phenotypes of new daylily cultivars.

Open Access

Abstract

Pollen stainability, frequency of unreduced pollen grains, and pollen diameter were examined in 13 species and 4 interspecific hybrids of Vaccinium comprising 3 ploidy levels. Pollen in the tetraploid species was potentially more fertile (as judged by stainability) than in the diploid species. Pollen stainability in the hexaploids was not different from the diploids or tetraploids. Four pollen viability classes (good, fair, poor, and very poor) were established among species. Practically all of the species studied produced unreduced pollen grains. Mean pollen diameter was 11% larger in the tetraploids than in the diploids and 11% larger in the hexaploids than in the tetraploids. The normal pollen diameter ranges for the 3 ploidy levels of Vaccinium were calculated and presented as a possible taxonomic tool.

Genetic, rather than seasonal or environmental differences, appeared to account for the major portion of the interclonal and interspecific variation observed in pollen stainability and in the frequency of unreduced pollen grains.

Frequent irregularities observed were empty pollen grains and granular, unstained pollen, which were assumed to represent early postmeiotic abortions. Meiosis was studied in a representative species of each ploidy level. Pairing and segregation were essentially normal, but a few multivalents or pseudo-multivalents (bivalents secondarily associated) were observed in the hexaploid species.

Open Access

We are grateful to C. Hubbuch for systematic guidance in defining the list of species for this survey and to P. Andersen, B. Dehgan, and T. Walters for evaluation and suggestions for improving the manuscript. The cost of publishing this paper was

Free access

Genetically characterized isozyme loci are useful for taxonomic studies. In an initial study a few Ananas genotypes were used to determine which enzyme systems would give well-resolved banding patterns on starch gels. The enzyme-staining systems that resulted in well-resolved banding patterns were used to survey more Ananas genotypes to identify and characterize isozyme polymorphism. Genetic studies were performed using seedling populations to determine the basis of variability observed among genotypes. Two peroxidase loci and three phosphoglucomutase loci were identified and characterized. Information from these studies, was used to formulate a system by which species and plant introductions could be identified and distinguished.

Free access

Eighteen isozyme systems were surveyed in the peach [Prunus persica (L.) Batsch.] plant introduction collection. Seven systems were polymorphic. Three previously unreported isocitrate dehydrogenase (IDH; EC 1.1.1.41), three malate dehydrogenase (MDH; EC 1.1.1.37) and two shikimate dehydrogenase (SDH; EC 1.1.1.25) banding patterns were detected in the clones. Isocitrate dehydrogenase was dimeric in structure, with two alleles present at a single locus. Malate dehydrogenase was dimeric in structure, with three alleles present at the fast locus, while a second locus was monomorphic. Shikimate dehydrogenase was monomeric, with one allele present in most clones, while PI 113452, PI 113650, and PI 117679 were heterozygous for a slow SDH allele. Electrophoretic evidence suggests PI 113452, PI 113650, and PI 117679 are peach × almond (P. dulcis Webb) hybrids, since they were heterozygous for alleles previously reported only in almond.

Free access

Nineteen polymorphic and eleven monomorphic isozyme loci were identified in thirteen enzyme systems in a survey of four-hundred melon (Cucumis melo L.) accessions. Segregation of allozymes in F2 and backcross (BC) families for isozyme loci agreed with the expected 1:2:1 and 1:1 segregation ratios (P <0.01). Eleven isozyme loci were linked and were integrated to form a map containing two linkage groups spanning 98 cM with a mean linkage distance of ≈9 cM. Linkage groups (A and B) contain the following loci in the order: A Fdp-2, Pgd, Pgm, Mpi-1, Idh, and Ac, and B Pep-gl, Mdh-2, Mdh-4, Mdh-5, Mdh-6. The remaining eight loci (Acp-1, Acp-4, Ak-4, Fdp-1, Gpi, Mpi-2, Pep-la, and Pep-pap) segregated independently. The isozyme map constructed in this study provides genomic information for future linkage studies with economically important traits and concensus map construction through map merging.

Free access