Sweetpotato varieties differ in their ability to efficiently use N. This study was conducted to determine if time of N application affected root yield and quality in the variety Beauregard. Nitrogen sidedress single-application treatments were applied at 10, 21, 28, and 35 days after transplanting. Two split application treatments were evaluated: l) 44.8 kg N/ha were applied 10 days after transplanting and 22.4 kg N/ha applied 21 days after transplanting and 2) 33.6 kg N/ha were applied 21 and 35 days after transplanting. The N source was calcium nitrate (15.5–0–0) and totaled 67.3 kg N/ha for all treatments. Plots were four rows and 6 m long, and treatments were randomized in five blocks. Harvested roots were sorted according to U.S. Dept. of Agriculture grading standards and weighed. Highest yields of U.S. no. 1 grade roots were obtained by applying N 21 to 35 days after transplanting. Total marketable yield was highest when application was made at 28 or 35 days after transplanting. Root length, at the 10% level of significance, was shorter when one vs. two N applications were applied. Using one N application compared with two N applications seems to be beneficial as shown by increased total marketable yields and yield of U.S. no. 1 roots and reduced root length.
Texas is botanically diverse with approximately 5500 native plants identified: east Texas contains about 40% of the total. While most species are stable, many are classified as rare, threatened, vulnerable, or endangered. Databases for east Texas plant communities and vegetative analyses are numerous. However, they are not yet integrated into easy-to-sort-and-query computer files. Computer-Assisted Drafting (CAD) and Geographic Information Systems (GIS) technology offers powerful applications to the storage, management, and spatial analysis of species inventories, plant community dynamics, and long-term habitat monitoring. At SFASU, the College of Forestry's GIS Center is being utilized to develop comprehensive east Texas resource inventories on a ten-station HP Apollo/ArcInfo platform. In the horticulture program, a twenty-station PC/AutoCad teaching laboratory is being used to create layered maps of the SFASU Arboretum, the on-campus landscape and off-campus plant communities. The integration of CAD and GIS projects through a DXF format takes advantage of the attributes of both technologies.
Twenty cranberry (Vaccinium macrocarpon) genotypes were evaluated for five seasons in an experimental upland planting in southwest Michigan. Beds were constructed on a silty clay loam soil by excavating to grade, and filled with 30 to 45 cm of sand. Four 2 × 2-m plots of each genotype were planted in 1996. Fruit were harvested with hand scoops from 2000 to 2005. Yield per plot, average berry weight, and percent berries exhibiting decay were determined. Sound fruit were also stored at 2 °C for 4 to 8 weeks and sorted to determine the percentage of fruit developing decay in storage. Fungi were isolated and identified by morphological characteristics. Genotypes producing the highest average yields were `Stevens', `Ben Lear', #35, `LeMunyon', and `Franklin'. Varieties with the highest average berry weight were `Pilgrim', `Stevens', `Baines', `Beckwith', `Searles', and #35. Genotypes with lower rot incidence at harvest were #35, `Early Black', and `Foxboro Howes', whereas `Howes' and #35 developed the least rot during storage. Fungi commonly isolated from decaying fruit were Colletotrichum sp., Coleophoma empetri, Phomopsis vaccinii, Phyllosticta vaccinii, Fusicoccum putrefaciens, Botrytis cinerea, Pestalotia sp., and Allantophomopsis sp. Prevalence of specific fungi differed among cranberry genotypes.
Strawberry fruit were harvested on three different dates from the Strawberry Association plot (cv. Festival), a commercial farm (cv. Camino Real), and at the University of Florida Gulf Coast Research and Education Center (cv. Sweet Charlie), in central Florida in 2005 and 2006. Fruit were transported to the USCSPL in Winter Haven, Fla., sorted, dipped for 10 s in treatment solutions, drained and stored in commercial clam-shells at 15 to 19 °C. Percentage of decay (number of fruit with lesions) was monitored during storage. There were 10 fruit per replicate clamshell, and three to four replicates per treatment for each harvest. Treatments included three size classes of galacturonic acid (GA) oligomers with a degree of polymerization (DP) ranging from 1–13, 8–24, and 22–46 and undigested polygalacturonic acid at 0.2% in 50 mmol LiOAC, LiOAC/NaOAC, with 22% ETOH, or KOAC buffer (all buffers at pH ≈4.4), prepared by enzymatic digestion followed by differential pH and alcohol precipitation. The main pathogens found on these fruit were Rhizopus stolonifer and Botrytis cinera at 1×105 cfu/g fruit in 2005 and 5×107 in 2006. The medium range oligomers (DP 8-24) reduced decay significantly compared to buffer alone or to the lower or higher DP GA oligomers, and elicited ethylene production. Oligomers in this pectin size class have previously been reported to elicit ethylene and plant defense responses in plant tissues.
Lettuce mosaic has been a serious virus disease for lettuce in all locations worldwide where lettuce has been grown. Consequently, the disease and its virus have been well studied. Lettuce plants react to lettuce mosaic virus in a variety of ways. The most common susceptible reaction is an overall vein clearing and mottling, followed by leaf recurving, leaf distortion, and stunting. However, some susceptible types manifest a mild mottling with little additional distortion. Others develop a necrotic reaction, which may be severe, mild, or seasonal. Finally, there are at least three resistant reactions, most frequently appearing as a systemic infection manifested with restricted yellowish lesions. Research is ongoing to sort out the various reactions and their genetic bases. This report describes the inheritance of the severe necrotic reaction and its relationship to the resistant reaction conferred by the allele mo-1. Several previous crosses among necrotic types indicate that the same necrotic allele is operating except that found in `Bibb'. Several crosses were studied. The cross `Salinas' (mot.) × `Crisp As Ice' (nec.) showed that necrotic is due to a single dominant allele. The cross `Salinas 88' (res.) × `Maikonig' (nec.) produced three phenotypes in F2, indicating the action of two loci. The crosses PI 251245 (res.) × `Prizehead' (nec.) and `Vanguard 75' (res.) × `Prizehead' disclosed two recombinant phenotypes, mottled and resistant-necrotic. Necrotic is dominant to nonnecrotic in both susceptible and resistant phenotypes. The genes are inherited independently.
In 2004, the greenhouse and nursery industry was ranked as the fourth largest crop group in the United States based on farm cash receipts (USDA, 2004). The ornamental crop sector was expected to post total sales in excess of 15.3 billion dollars in 2004 (USDA, 2004). Landscape services within the green industry have risen from 28.9 billion in 2002 to 41.6 billion in 2004 (ALCA, 2004). In Iowa, recent surveys of turfgrass and edible food crop production and services have shown a combined net worth of more than 1 billion dollars. However, these surveys failed to include nursery and garden centers, greenhouse growers, landscape designers/contractors, arborists, and florists. Therefore, the objective of this project was to better understand the scope and scale of the ornamental horticulture industry in Iowa. A questionnaire was developed and mailed to 1293 horticulture businesses in Iowa. The survey instrument was developed with input from members of the Iowa Nursery and Landscape Association Research Corporation. Before mailing, it was reviewed by survey professionals and piloted to a select group of green industry representatives and edited per their suggestions. Three weeks after mailing, a reminder postcard was sent. Respondents were sorted as to type and size of business, number of employees, and annual sales. The percentage of gross receipts was categorized by types of plants sold and services provided. Respondents also were asked about the factors that limit their success, their strengths compared to competitors, and their expectations for future growth.
Temperature management of fresh products begins with proper handling at harvest. Inadvertent abuses, such as lengthy delays to cool or exposure of harvested product to the sun, can detrimentally impact postharvest quality. We used mature-green bell peppers to determine the periods of sun exposure (midday during August in Davis, Calif.) necessary to affect quality attributes (visual appearance, gloss, weight loss, and firmness). Peppers were evaluated after cooling, storage at 7.5 °C for 3 or 7 days, and storage plus 2 days at 20 °C. The impacts of sun exposure, although sometimes barely detectable after cooling, became more noticeable once the peppers were stored. The additional transfer period to 20 °C after storage further accentuated the impact of the exposure. Depending on the experiment, sun-exposed areas reached 45 to 55 °C within 1 hour. Peppers typically lost 0.4% to 0.5% and 1.0% to 1.3% weight during 1- and 2-hour exposures, respectively. Changes in gloss and firmness (whole fruit compression and pulp penetration) were preceded by changes in visual appearance. Exposure to the sun for 0.5 hour did not impact postharvest quality of peppers. Exposures from 1 to 1.5 hours usually resulted in changes apparent only after the storage period. Such exposures are problematic in commercial situations because these peppers are unlikely to be eliminated during sorting on the packingline. Exposures of 1.5 to 2 hours usually resulted in an immediate change in appearance (pitting, blistering, color change).
Potatoes with hollow heart or brown center are considered to be of poor quality for both fresh and processing markets. A reliable nondestructive method, which can distinguish affected and normal potatoes, is described here. A Varian 4.7 Tesla, 33-cm horizontal-bore spectroscopy/imaging system was used to obtain nuclear magnetic resonance (NMR) images of potatoes. A two-dimensional multi-slice spin-echo imaging technique was used to acquire the cross-sectional images along the longitudinal direction. The echo time was 35 msec and the repetition time was 1.2 sec. A total of 13 slice images were taken for each potato. A one-dimensional projection technique was also performed to evaluate the possibility of using fast-scan method. The brown center showed high intensity in long echo scans due to its longer TL relaxation time. A suberin-like layer resembling the periderm developed on the cavity wall of hollow heart causing a tan or dark brown coloration. This cavity wall also appeared in high intensity on the image. The affected potatoes can easily be sorted out using this nondestructive NMR imaging technique.
The nature and magnitude of genotype × environment interactions will determine the extent of testing required (locations, years) to accurately evaluate a genotype's performance. Data from yearly T-AES muskmelon variety trials were analyzed to determine the level of variety (V) × year (Y), V × location (L), and V × Y × L interactions for yield and fruit size. Data analyzed were of nine hybrids grown at three commercial farms over two years. Fruits were harvested similar to grower practices, and were sorted into size classes (9 - 30) or culls. V × Y and V × L interactions for marketable yield and total yield were not significant. V × Y × L interaction was significant for marketable yield, but not for total yield. V × Y × L interactions were highly significant for percentage culls and percentage of fruit in each size class. V × L interactions were also significant for percentage of fruit in most size classes. Data indicate that specific location-year combinations differentially affect a genotype's fruit size, most likely due to weather, planting time, and stress factors. Multiple year and location testing of genotypes is therefore critical, particularly for evaluation of fruit size.