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  • Author or Editor: J.B. Jones x
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Abstract

In Florida, most producers of cut chrysanthemums (Dendranthema grandiflora Tzvelev.) use overhead irrigation systems and fertilize with soluble fertilizer injected through the system. Trickle irrigation can be used to produce cut chrysanthemums with substantial savings in water (2). Controlled-release fertilizers can be successfully used to produce cut chrysanthemums (1) and may be advantageous in certain production situations (3). Direct yield comparisons influenced by the four possible combinations of irrigation and fertilization practices have not been researched in previous studies. We, therefore, evaluated main and interactive effects of overhead or trickle irrigation in conjunction with soluble or controlled-release fertilization on the yield and postharvest quality of cut chrysanthemums.

Open Access

Abstract

Most of the leaf Ca collected from healthy and declining peach trees (Prunus persica L. Batsch. cv. Loring) growing on both limed and unlimed field plots was found to be non-extractable in acetic acid irrespective of leaf age, health status, or lime treatment. The concentration of extractable leaf Ca was less than 100 parts per million. Concentration of total Ca was highest in leaves from declining trees but declining trees had fewer and smaller leaves resulting in less total Ca in decline as compared to healthy trees. Large numbers of Ca-oxalate crystals were observed throughout the leaf and stem tissues. Crystals were primarily concentrated in leaf midveins. Midvein sections of leaves from decline trees contained greater numbers of crystals per unit area than did those from healthy leaves from healthy trees.

Open Access

Abstract

Increased temperature of the growing bed had no effect on fruit yield, fruit cracking, skin strength, or plant growth of tomato (Lycopersicon esculentum mill.). Yield losses from cracking were 2, 16 and 35% in the fall, spring and summer crops, respectively. The pink-fruited ‘Ohio-Indiana Hybrid O’ and ‘Missouri Hybrid 756’ had greater fruit losses due to cracking than the red-fruited ‘Floradel’ and ‘Rapids’. Large fruit were more susceptible to cracking. Fruit cracking in the fall crop was predominantly concentric in nature whereas cracked fruit in the summer was predominantly radial. Skin puncture resistance was inversely related to fruit cracking.

Open Access

Tomato (Lycopersicon esculentum Mill.) accessions were tested for hypersensitivity and rated for resistance following field inoculation with tomato race 3 (T3) of the bacterial spot pathogen Xanthomonas campestris pv. vesicatoria (Doidge) Dye (Xcv) in 1992 and 1993. Hawaii 7981, PI 126932, PI 128216, and selections of the latter two expressed hypersensitivity. Hawaii 7981, only tested in the field in 1993, was nearly symptomless and developed significantly less disease than any other accession. PI 128216 had a level of disease similar to susceptible `Solar Set' when tested in 1993. However, a selection from it (PI 126218-S) was significantly more resistant than `Solar Set' in both years. Although PI 126932 had a level of disease similar to `Solar Set' in both years, a selection from it (PI 126932-1-2) was significantly more resistant than `Solar Set' in 1993. Other accessions without hypersensitive responses but more resistant than `Solar Set' for two seasons were PI 114490, PI 126428, PI 340905-S, and PI 155372. Hawaii 7975 was significantly more resistant than `Solar Set' in the one season it was tested.

Free access

Abstract

Glasshouse microclimate during 3 growth periods in the Southern Piedmont region of the United States was characterized. An increase in density of tomato plants (Lycopersicon esculentum Mill.) by one-third, which doubled radiation interception, was suggested by early observations. Maintenance of clean glass surfaces was found to be particularly important during cloudy weather. There was no significant difference between mean air temperature and mean rooting media temperature in the raised beds used. CO2 concentration was found to be low (240 ppm) when fans were not circulating outside air. CO2 generators, installed to increase greenhouse CO2 levels, were not effective possibly because control was inadequate. The use of CO2 enrichment requires further study under Southeastern conditions. Relative humidity remained below the recommended 90% in the green-house except during cloudy-mild weather. Although inside relative humidity was generally less than outside relative humidity, values ranged from 90 to 100%.

Open Access

Crosses were made between tomato (Lycopersicon esculentum Mill.) inbreds susceptible to races T2 and T3 of bacterial spot (Xanthomonas vesicatoria and Xanthomonas campestris pv. vesicatoria, respectively) and accession PI 114490 with resistance to races T1, T2, and T3. Resistance to race T2 was analyzed using the parents, F1, and F2 generations from one of the crosses. The F1 was intermediate between the parents for disease severity suggesting additive gene action. The segregation of F2 progeny fit a two-locus model (χ2 = 0.96, P = 0.9-0.5) where four resistance alleles are required for a high resistance level, two or three resistance alleles provide intermediate resistance, and zero or one resistance allele results in susceptibility. The narrow sense heritability of resistance to T2 strains was estimated to be 0.37 ± 0.1 based on F2 to F3 parent-offspring regression. A second cross was developed into an inbred backcross (IBC) population to facilitate multilocation replicated testing with multiple races. Segregation for T2 resistance in the inbred backcross population also suggested control was by two loci, lending support to the two-locus model hypothesized based on the F2 segregation. To determine if the same loci conferred resistance to the other races, selections for race T2 resistance were made in the F2 and F3 generations and for race T3 resistance in the F2 through F4 generations. Six T3 selections (F5), 13 T2 selections (F4's that diverged from seven F2 selections), and control lines were then evaluated for disease severity to races T1, T2, and T3 over two seasons. Linear correlations were used to estimate the efficiency of selecting for resistance to multiple races based on a disease nursery inoculated with a single race. Race T1 and race T2 disease severities were correlated (r ≥ 0.80, P< 0.001) within and between years while neither was correlated to race T3 either year. These results suggest that selecting for race T2 resistance in progeny derived from crosses to PI 114490 would be an effective strategy to obtain resistance to both race T1 and T2 in the populations tested. In contrast, selection for race T3 or T2 will be less likely to result in lines with resistance to the other race. PI 114490 had less resistance to T3 than to T2 or T1. Independent segregation of T2 and T3 resistance from the IBC population derived from PI 114490 suggests that T3 resistance is not controlled by the same genes as T2 resistance, supporting the linear correlation data.

Free access

An efficient deoxyribonucleic acid (DNA) extraction procedure that yields large quantities of DNA would provide adequate DNA for a large number of different analytical procedures. This study was conducted to compare three DNA extraction procedures for cost, time efficiency, and DNA content while extracting DNA from Kentucky bluegrass (Poa pratensis L.). Three students at the Univ. of Illinois with varying levels of DNA extraction experience conducted DNA extractions using Plant DNeasy™ Mini Kits, Plant DNAzol® Reagent, and a PEX/CTAB buffer. Costs varied significantly with cost (US$) per DNA sample of $3.04 for the DNeasy™ method, $0.99 for the DNAzol® method, and $0.39 for the PEX/CTAB extraction. The DNAzol® method was the fastest; although extracting 2.8 ng less DNA than the DNeasy™ method, it did not require the use of hazardous organic solvents, and random amplified polymorphic DNA (RAPD) markers were satisfactory for DNA fingerprinting of Kentucky bluegrass cultivars. The PEX/CTAB method, which did not include a tissue homogenization step, did not have reproducible banding patterns due to miniscule and inconsistent quantities of DNA extracted, or possibly due to inadequate purification. The investigator with the least DNA extraction experience was the slowest, while extracting 75% more DNA. All three methods are easily adapted to laboratories having personnel with different levels of experience. The DNAzol® Reagent method should save time and money, with reproducible results when many individual plant samples need to be identified. Chemical names used: potassium ethyl xanthogenate (PEX); cetyltrimethyl ammonium bromide (CTAB)

Free access

Abstract

Increases in the darkness and redness of both thawed and cooked highbush blueberries (Vaccinium corymbosum L.), indicated by tristimulus measurements, were cultivar-related but not dependent on blueberry pH or anthocyanin content. Waxy bloom was retained in thawed berries but lost during cooking. Pigmented exudate appeared with some cultivars during thawing. Differences among cultivars in exudate formation and reddening during thawing are explained in terms of changes in epidermal cells, cuticle, and wax structure which were observed by light and electron microscopy. The color of blueberry cooking water depended primarily on the berry anthocyanin content, acidity, and the extent of leaching.

Open Access