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- Author or Editor: Craig K. Chandler x
The objective of this study was to compare plant health and growth in Florida fruiting fields of `Sweet Charlie' plants from 10 different plant sources. Bare-root plants from Ontario, Nova Scotia, Massachusetts, Oregon, North Carolina, Alabama, and Florida and plug plants from North Carolina and Florida were compared in a RCBD of four replicates. Plants were rated for vigor, production, diseases, and pests throughout the 1995-96 season. Crown size of transplants ranged from 7 to 12 mm. Plants from northern sources exhibited angular leaf spot (Xanthomonas fragariae) and gnomonia (Gnomonia spp.) while southern-raised plants were infected with phomopsis (Phomopsis obscurans) and anthracnose (Colletoctrichum spp.). Initial ratings confirm the potential for aphids and two-spotted spider mites (Tetranychus urticae) to be introduced on transplants. Plants from northern origins flowered 10-14 days earlier than plants produced in southern regions. Total season marketable fruit production was not statistically different among the eight bare-root treatments. Monthly fruit production was significantly different among treatments for all months except February. Performance of plug plants compared to bare-root plants of the same geographic origin were inconsistent. Initial crown size, average berry size, and cull fruit production were significantly different among the plant sources. In summary, clear differences in foliar diseases and monthly fruit production were strongly associated with transplant source. A strawberry farmer may maintain more stable production throughout the year by using transplants from several geographic origins.
Genotype × environment interaction for resistance to the twospotted spider mite (Tetranychus urticae Koch) of eleven clones of Fragaria L. sp. (strawberries) grown in six environments throughout the United States was examined using two multivariate analysis techniques, principal coordinate analysis (PCA) and additive main effect and multiplicative interaction (AMMI). Both techniques provided useful and interesting ways of investigating genotype × environment interaction. PCA analysis indicated that clones X-11 and E-15 were stable across both low and high environments for the number of spider mites per leaflet. The initial AMMI analysis showed that the main effects of genotype, environment, and their first-order interaction were highly significant, with genotype × environment interaction due mainly to cultivar `Totem' and environment FL94. A second AMMI analysis, which excluded `Totem' and FL94, showed that the main effects of the remaining genotypes, environments, and genotype × environment interaction were also highly significant. AMMI biplot analysis revealed that FL93 and GH93 were unstable environments, but with opposite interaction patterns; and GCL-8 and WSU2198 were unstable genotypes with similar interactions that were opposite those of WSU 2202.
`Oso Grande' and `Sweet Charlie' strawberries (Fragaria × ananassa Duch.) in 1991-92 and `Oso Grande' and `Seascape' in 1992-93 were grown in a K fertilization study using polyethylene-mulched and fumigated beds. Potassium was injected weekly into the drip irrigation system at 0.28,0.56,0.84, 1.12, and 1.40 kg K/ha per day. Early, March, and total-season marketable fruit yields were not affected by K rate during either season. The average fruit weight of `Oso Grande' for the early, March, and total-season harvest periods in the 1992-93 season decreased with increased K rate. For the same harvest periods, `Seascape' average fruit weight increased, decreased, and did not change, respectively, with increased K rate. Cull fruit yield during both seasons and fruit firmness during the 1992-93 season were not affected by K rate. Petiole sap, whole leaf, and leaf blade K concentrations increased with increasing K rates on most sampling dates during both seasons. `Oso Grande' and `Sweet Charlie' produced similar total marketable fruit yields the first season, but `Oso Grande' produced higher total yields than `Seascape' during all harvest periods of the second season.
The effects of cultivar, harvest date, and production year on the soluble solids and antioxidant phytochemical levels of 22 strawberry (Fragaria ×ananassa Duch.) genotypes grown in a winter annual hill (raised bed) production system were investigated. Fruit harvested in Jan. 2003 and 2004 were characterized by low polyphenolic content, but high concentrations of soluble solids and ascorbic acid; whereas fruit harvested in Feb. 2003 and 2004 generally had elevated polyphenolic concentrations, but lower levels of soluble solids and ascorbic acid. Annual variation in soluble solids and phytochemical composition was also observed among nine strawberry genotypes, which was likely attributable to variations in solar radiation and air temperature. `Earlibrite' was among the highest for soluble solids concentration on three of the four harvest dates, while `Carmine' was noted for its high phytochemical concentrations across harvest dates and years. The breeder selection `FL 99-117' emerged as a promising selection in terms of producing fruit with high concentrations of soluble solids and antioxidant phytochemicals.
Transplant quality can have a major effect on the productivity of many crops. Bare-root, green-top transplants for Florida winter strawberry (Fragaria ×ananassa) production are produced mainly in highlatitude (>42° N) nurseries. Mechanical digging machines are used to remove plants from the soil at these nurseries before transport to production fields in Florida. In the course of this operation, crowns, petioles, and leaves may be crushed and broken. Machine and hand-dug bare-root transplants of `Camarosa' and `Sweet Charlie' were obtained from a Nova Scotia, Canada nursery, planted at the Gulf Coast Research and Education Center, Dover, Fla. field facility on 2 Nov. 1999 and 10 Oct. 2000, and grown using standard annual-hill production practices. Plots were harvested twice weekly beginning 5 Jan. 2000 and 15 Dec. 2000. Hand-dug transplants produced significantly higher monetary returns both seasons. Therefore, fruit producers may consider paying the higher cost associated with changes in harvesting and packing operations needed to reduce damage to transplants.
‘Rubygem’, a new short-day strawberry (Fragaria ×ananassa Duch.), produces high yields of moderately firm, attractive well-flavored fruit from late autumn through early spring in the strawberry-growing district in Southeast Queensland. ‘Rubygem’ is recommended for trial in areas with mild winter climates, especially where rainfall is unlikely and a well-flavored berry is required.
The effect of altered red/far-red light environment on subsequent field performance of strawberry plug plants was tested. Two wavelength-selective plastic films were compared to neutral shade and full-sun control for conditioning `Chandler' strawberry plug plants before transplanting to a winter production system. The following year, plug plants of `Chandler', `Sweet Charlie', and `Allstar' were conditioned under the same treatments, with the addition of a continuous incandescent light and a short-day photoperiod, and plant performance was followed in the winter production system in Florida, a cold-climate annual hill system in Maryland, and in a low-input greenhouse production system. During the first year, the red light-filtering film slightly advanced fruiting in Florida. However, during the second year, the effect of the red light-filtering film was not significant, and a short-day treatment resulted in a greater reduction in runnering and increased early crown and flower development. For June-bearing strawberry plants maintained above 20 °C, altering the red/far-red environment did not consistently advance flowering.