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Abstract
Treatments of 0, 2% and 4% Folicote in water were applied to runoff at 0, 7 and 16 days after bloom (DAB) on ‘Norgold Russet’ potatoes (Solanum tuberosum L.) grown in the greenhouse. Folicote is a wax emulsion antitranspirant (AT) containing 60% solids. Treatments at 0, 7 and 16 DAB with 2% AT reduced water uptake by >20% for 4, 8, and 14 days respectively, following application. AT treatment at 4% reduced water uptake >40% for 10-14 days. There was no significant reduction of tuber yield even at the higher concentration.
Abstract
Pre-germinated onion (Allium cepa L. cv. New Mexico White Grano) seeds, sown in Olton sandy loam soils at 1.7–7.3°C began to emerge after 7 days compared with 30 days for dry non-germinated seeds. Plant stands were established with pre-germinated seeds 12 days earlier than with non-germinated dry seeded onions. The earlier emergence and more rapid growth achieved by pre-germinated seedlings resulted in 10 to 12 days earlier maturity and a 37.5% increase in bulb diameter at harvest. Increased bulb diameter placed 58% of the yield in the 5.1–7.7 cm (2-3 inch) diameter grade compared to 29% for checks and yield of marketable onions was significantly improved.
Abstract
The economic feasibility of using hexazinone for weed control in lowbush blueberries (Vaccinium angustifolium Ait.) was determined by using the partial budgeting technique. Four rates of hexazinone were evaluated to determine the effect on net income in a blueberry enterprise. Response function analysis also was utilized to ascertain the hexazinone level that would maximize blueberry yield and profitability. Partial budget analysis indicated that hexazinone use at 1.1, 2.2, and 4.5 kg/ha was expected to increase net income, indicating its use was economically feasible. Hexazinone use at 9 kg/ha was judged to be economically infeasible, since it decreased net income. Response function analysis revealed that 2.3 kg/ha of hexazinone maximized profits. Chemical names used: 3-cyclohexyl-6-(dimethylamino)-1-methyl-1,3,5-tria-zine-2,4(1H,3H)-dione (hexazione).
Flowering (Cornus florida L.) and kousa (C. kousa Hance) dogwoods are ornamental trees valued for their four-season appeal, but also for their importance to retail and wholesale nurseries. The popularity of kousa dogwood has increased in recent years as a result of its resistance to dogwood anthracnose and powdery mildew as compared with flowering dogwood, which is typically susceptible to those diseases. This range of resistance allows the development of intra- and interspecific cultivars with multiple disease resistance or a combination of disease resistance and specific ornamental traits. Breeding requires controlled crosses that are usually done manually, which is a labor-intensive process. Cornus florida and C. kousa have generally been found to be self-incompatible allowing for the breeding process to be made more efficient by not having to emasculate flowers. We have capitalized on the natural ability of honeybees and the self-incompatible nature of dogwood to perform self- and crosspollinations of flowering and kousa dogwood. Self-pollinations were conducted in 2006 and 2007 with C. florida ‘Appalachian Spring’ and ‘Cherokee Brave’ and with C. kousa ‘Blue Shadow’ and Galilean®. The flowering dogwood self-pollinations resulted in no seed production, whereas the kousa dogwood self-pollinations resulted in low seed production, indicating self-incompatibility. Intra- and interspecific crosses of flowering and kousa dogwood cultivars and breeding lines were conducted in 2006 to 2008. Honeybees were effective in facilitating seed production for all intraspecific crosses conducted. Seedling phenotypes of putative intra- and interspecific hybrids are similar and practically indistinguishable, so dogwood-specific simple sequence repeats were used to verify a sample of the putative hybrids. The results demonstrated that honeybees were effective in performing controlled pollinations and that honeybee-mediated pollinations provide an alternative to time-consuming hand pollinations for flowering and kousa dogwood.
Cross-species transferability of simple sequence repeats (SSRs) is common and allows SSRs isolated from one species to be applied to closely related species, increasing the use of previously isolated SSRs. The genus Cornus consists of 58 species that are ecologically and economically important. SSRs have previously been isolated from C. florida and C. kousa. In this study, 36 SSRs were tested on taxa from 18 Cornus species and hybrids for cross-species transferability and genetic diversity was calculated for each locus using polymorphism information content (PIC). Cross-species transferability of SSR loci was higher in more closely related species and PIC values were high. Evidence was found for conserved primer sites as determined by the amplification of SSR loci in the taxa examined. Polymerase chain reaction products were cloned and sequenced for three SSR loci (CF48, CF59, and CF124) and all individuals sequenced contained the appropriate repeat. Phylogenetic relationships of 14 Cornus species were inferred using nucleotide sequences of SSR locus CF48. The most parsimonious tree resulting from this analysis was in concordance with phylogenies based on matK and internal transcribed spacer sequences. The SSR loci tested in this study will be useful in future breeding, population, and genetic studies within Cornus.
Flowering dogwood (Cornus florida) and kousa dogwood (C. kousa) are popular ornamental species commonly used in the horticultural industry. Both trees are valued for their beautiful floral display and four-season appeal. Species-specific simple sequence repeat (SSR) loci were used to genotype and assess genetic diversity of 24 flowering dogwood cultivars and breeding lines and 22 kousa dogwood cultivars. Genetic diversity was determined by allele sharing distances and principal coordinate analysis and was high in both species. Molecular identification keys were developed for cultivars and breeding lines of each species using a few polymorphic SSRs loci (four in C. florida and five in C. kousa). Most (18 of 24) of the flowering dogwood and all (22 of 22) kousa dogwood accessions could be distinguished from each other using these SSRs; those that could not were resolved using DNA amplification fingerprinting. The reliability of both keys was assessed using five anonymous cultivars for each dogwood species, which were correctly identified using the molecular keys. The genetic information presented here will be useful for identification and verification of cultivars for nurseries and as molecular markers for breeders and researchers.