Search Results

You are looking at 1 - 10 of 33 items for

  • Author or Editor: A. C. Miller x
Clear All Modify Search

Abstract

The effect of 2-chloroethanepliosphonic acid (ethrel) on the sex expression of pickling cucumbers was studied. Tests to determine concentrations, effect on sex expression, and yield potential were conducted in greenhouse and field situations.

As many as 19 successive pistillate nodes were observed for the treated monoecious cultivar ‘SC 23’. The most effective concentrations of ethrel were 120, 180 and 240 ppm for these studies. These rates in single or multiple application resulted in the greatest number of continuous female nodes with the least shortening of internodes. A much lower concentration of 24 ppm had little effect as to stunting and only limited effect on sex conversion. Significant yield increases, as measured by value per acre, were obtained for 3 monoecious cultivars, ‘Model’, ‘SC 23’ and ‘Chipper’, treated with ethrel.

Open Access
Authors: and

Abstract

Pinto bean plants (Phaseolus vulgaris L. cv. Pinto 111) in the unifoliolate leaf stage were exposed for 3 hours to 0.8 ppm SO2, 0.25 ppm 03, or a mixture of the 2 pollutants at these concentrations at 15, 24, or 32° C. Foliage exposed to O3 alone developed adaxial stipple and leaves exposed to SO2 alone developed interveinal necrosis. The mixture of O3 and SO2 induced O3-type symptoms at 32° and SO2-type symptoms at 15°. Both symptom types were present at 24°. Some abaxial glazing or silvering was also induced by the mixture, and was most common at 15° and 24°. Ozone and SO2 each induced greater foliar injury at 15° or 32°, as compared to 24°. The mixture of O3 and SO2 induced greatest macroscopic foliar injury at 15°. The degree of adaxial vs abaxial leaf surface injury varied with temperature.

Open Access

Peroxidase activity in extracts from freeze-dried tissue of Fragaria × ananassa Duch. cv. Chandler was highest in tissue-cultured (TC) plants, followed by field-grown (FG) and lowest in greenhouse (GH) plants. Among tissue types, activity was highest in petioles, with leaves second highest. Fruit, root, and crown tissue all exhibited low or no activity. When subjected to isoelectric focusing (IEF), petiole tissue extracts exhibited more isozymes than extracts from other organs regardless of staining substrate. Using 4-chloro-1-naphthol and H2O2 as substrates, anionic and cationic isozymes were observed in TC petiole extract with nine isozyme bands ranging in pI from 3.9 to 9.5. In TC leaf extract an isozyme at pI 7.4 was observed that was not present in other organ extracts when H2O2 and benzidine, p-phenylenediamine or 3-amino-9-ethylcarbazole were used as substrates. Specific isozymes and number of isozymes varied according to plant organ and developmental stage. Mature leaves and over-ripe fruit appeared to exhibit more activity and a larger number of isozymes than developing tissues of those plant organs.

Free access

Abstract

‘Royal Blackeye’ southernpea [Vigna unguiculata (L.) Walp.] was released in 1985 by the Louisiana Agricultural Experiment Station. This southernpea was developed primarily for local fresh market use. The purple hulls and blackeye seed coat pattern combination is unique among released cultivars.

Open Access

Abstract

Twenty-one cultivars of vegetables were treated in the greenhouse with Ethrel (2-chloroethanephosphonic acid) at concentrations of 240, 480 or 960 ppm. The stages of growth at treatment varied from 1 to 4 true leaves for the various cultivars.

The earliest observable response was stunting. With some cultivars, the stunting was permannent; but with others it appeared to be temporary. The degree and duration of stunting varied with cultivar and ethrel concentration.

Ethrel caused a strong tendency toward pistillate flowers on most of the monoecious cucurbits tested and in some cases almost complete absence of staminate flowers. The chemical greatly reduced the number of staminate flowers but had no observable effect on the number of perfect flowers of the muskmelon. The chemical also altered fruit shape of ‘Butternut’ squash.

Open Access

Much fresh-cut apple research has focused on browning, yet little sensory and flavor analysis has been performed. We therefore evaluated postharvest and flavor changes in stored fresh-cut `Gala' apples prepared after harvest or after CA storage (3 months, 1.4% CO2 and 3% O2). Apples were washed, cored, sliced, dipped in browning inhibitors (BI; Na-erythorbate + CaCl2), packaged in LLDPE bags, and evaluated for descriptive flavor attributes, GC volatiles, firmness, CO2 and O2 and color after 0, 2, 7, and 14 days at 1 °C. Initial apple firmness pre-CA vs. post-CA was 38.3N and 32.7N. Bag O2 concentration dropped to 1% to 2% by day 14 and day 7 for pre- vs. post-CA, respectively. CO2 concentration in bags increased linearly through day 14 in both pre- and post-CA. All pre-CA Hunter L values were higher than post-CA for all treatments on all sampling days. Both BI treatments maintained color for 14 days, but freshly cut (FC) wedges were generally superior whereas stored untreated fresh-cut (SFC) wedges browned markedly by day 2. There was no apparent difference between BI levels in terms of browning or flavor. BI-treated wedges were rated more astringent than FC and SFC, especially after CA. With few exceptions, “fruity”, “raw/ripe apple,” and “sweet” attributes were higher in all pre- vs. post-CA treatments. This trend was conserved through 14 days of storage per treatment. “Sour” and “citrus” scores were higher after CA only in BI-treated wedges. Major compounds recovered were butanol, butyl acetate, hexanol, 2-methylbutyl acetate, amyl/isoamyl acetate, hexyl acetate, 2-hexenyl acetate, butyl 2-methylbutanoate, butyl hexanoate, hexyl butanoate, hexyl 2-methylbutanoate, hexyl hexanoate, isobutyl octanoate and α-farnesene. Flavor-related compounds varied markedly through storage and after CA. The GC volatile analysis will be presented along with any possible correlation to trained sensory evaluations.

Free access

Eight unique varietal grape juices were examined for their antioxidant characteristics and commercial potential compared to that of commercial `Niagara' and `Concord'. Grape juices were cold-pressed from mature grapes, clarified, preserved, analyzed for pH, soluble solid and titratable acidity levels, pasteurized at 73 °C for 12 seconds, and sampled for microbial testing. A preliminary panel of 41 routine evaluators assessed all juices for 18 quality characteristics against known and blind controls. Based on these results, `Reliance', `Traminette', and New York 73 juices were presented to a 107-member panel of untrained judges. Panelists rated experimental juices against commercial controls for color, appearance, aroma and flavor intensity, sweetness, tartness, overall quality, and preference. Among juices tested, `Reliance' and NY 73 offer the greatest potential as specialty grape juices. `Traminette', `Chardonel', `Chambourcin', and NY 62 may also have potential as grape juice cultivars, if processed to improve their color and clarity. Small juice lots were hand-pressed from mature grapes and examined for total anthocyanin and phenolic content, antioxidant characteristics (DPPH and FRAP) and levels of individual phenolic compounds via GC-MS. Total anthocyanin and phenolic contents of experimental juices varied from 0–1460 μg·gfw-1 and 1001–2850 μg·gfw-1, respectively, and were highest in NY 73. Estimates of antioxidant activity differed slightly among tests, but activity appeared highest in `Chambourcin' and NY 73 and lowest in `Reliance'. Levels of individual compounds varied substantially among juices.

Free access

A tissue culture protocol was developed that increased the germination percentage and decreased the lag time to germination for strawberry (Fragaria x ananassa Duch.) achenes. This technique involved cutting surface-sterilized achenes across the embryo axis then placing the shoot apex/radicle-containing sections on semisolid Murashige and Skoog medium lacking hormones. Cut achenes began germinating 5 days after culture and achieved maximum germination (97% to 100%) in less than 2 weeks, compared to whole achenes, which began to germinate 7 to 10 days after sowing and required more than 7 weeks for maximum germination (<50%). Enhanced germination of cut achenes was a general phenomenon since achenes from 231 hybrid crosses responded similarly. Following placement on culture medium, cut achenes could be stored up to 8 weeks at 4C then removed to 27C, where germination and seedling development occurred at percentages and rates comparable to freshly cut achenes. Achenes did not require stratification before cutting to exhibit increased germination. Nearly 100% of the achenes from freshly harvested red-ripe, pink and white strawberries germinated after cutting and culture, although cut achenes from white and pink berries germinated more slowly than those from red-ripe berries. Achenes from green berries, whether whole or cut, did not germinate. This method of “embryo rescue” could be used to generate more seedlings from poorly germinating hybrid crosses, would considerably decrease the time from sowing to seedling production compared to traditional means, and would produce seedlings of uniform age for subsequent field evaluation.

Free access

Studies were conducted on peach [Prunus persica (L.) Batsch] during 1988 to 1990 to test the performance of a tree-width rope-curtain bloom thinner and a rotating rope-curtain thinner. Six trips over the tree canopy were required with the tree-width rope curtain, and only one trip was required with the rotating curtain to thin to a spacing of about one flower per 9 cm of fruiting shoot length. Based on the number of flowers per square centimeter of branch cross-sectional area (CSA) immediately following thinning and the number of fruit per square centimeter of CSA following June drop, rope-curtain thinning was equal to hand-thinning at full bloom (FB). Rope-curtain thinning reduced hand-thinning time by 40% and increased harvest fruit weight by 10% to 20%. Research on various modifications in tree training/pruning indicated that performance of the mechanical thinner was negatively correlated with shoot density. Thinning was maximum on open-center-trained trees on which detailed pruning had been conducted to eliminate overlapping shoots.

Free 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