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  • Author or Editor: C.A. Campbell x
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An experiment was conducted to determine if gibberellic acid (GA; ProGibb, Abbott Labs) can be mixed with Aliette or Agri-Mek and oil to reduce application costs, without reducing GA efficacy, and if Silwet and Kinetic adjuvants enhance GA efficacy. Five tank mixes were tested along with a nonsprayed control. The tank mixes included: 1) GA, 2) GA + Silwet, 3) GA + Kinetic, 4) GA + Silwet + Aliette, and 5) GA + Silwet + Agri-Mek + oil. All compounds were applied at recommended concentrations. In September, ≈24 L of each tank mix was applied with a hand sprayer to mature `Hamlin' orange trees [Citrus sinensis (L.) Osb.] on sour orange (Citrus aurantium L.) rootstock. Peel puncture resistance (PPR), peel color, and juice yield (percent juice weight) were evaluated monthly between Dec. 1997 and Mar. 1998. On most sampling dates the fruit of treated trees had higher PPR and were less yellow in color than fruit from control trees. However, in Jan., fruit treated with GA + Silwet and GA + Kinetic had greater PPR than other treatments. In Feb., fruit treated with GA + Silwet + Agri-Mek + oil had the lowest PPR. The effect of the different tank mixes on juice yield was usually similar to the effect of the tank mixes on PPR and peel color. On 8 Jan. 1998, fruit from trees treated with GA alone yielded significantly more juice than fruit from control trees. On 24 Feb. 1998, fruit from trees treated with GA alone yielded more juice than fruit from the other treatments. Thus, GA efficacy is generally not reduced by these tank mixes, nor improved by adjuvants.

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Gibberellic acid (GA) applied in late summer or fall delays subsequent loss of peel puncture resistance (PPR) and development of yellow peel color in many citrus cultivars. Our objective was to determine the optimal time to apply GA for increasing juice yield of `Hamlin' sweet orange [Citrus sinensis (L.) Osb.]. Mature trees on sour orange (Citrus aurantium L.) rootstock were sprayed with ≈24 L of a solution of GA (45 g a.i./ha) and organo-silicone surfactant (Silwet, 0.05%). Trees were sprayed on 26 Aug., 9 Sept., 2 Oct. (colorbreak), or 13 Oct. 1997, or nonsprayed (control). Peel puncture resistance, peel color, and juice yield were evaluated monthly between Dec. 1997 and Mar. 1998. Fruit from trees sprayed with GA had peels with higher PPR and less yellow color than fruit of control trees for most of the harvest season. The effect of GA on PPR and peel color lasted about 5 months. Juice yield was usually numerically greater for GA-treated fruit than for nontreated fruit. Fruit treated with GA at color break had significantly greater juice yield when harvested in late February than fruit from control trees. Thus, GA applied at color break appears to be the most effective time for enhancing peel quality and juice yield of `Hamlin' oranges.

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Abstract

Effects of boric, indole-3-acetic, gibberellic, succinic and fumaric acids, and water extract from onion bulbs on onion pollen germination and tube growth were studied. Boric acid stimulated pollen germination and tube growth at 100 mg/liter but was toxic at 200 mg/liter. Indole-3-acetic acid slightly increased pollen germination and tube elongation at 0.05 mg/liter, but inhibited pollen tube growth at 200 mg/liter. Gibberellic acid not only enhanced germination percentage, but the higher concentrations also increased the pollen tube lengths. Succinic and fumaric acids stimulated germination, but pollen tubes burst at the higher concentrations. At 200 mg/liter of fumaric acid no germination of pollen grains was observed, but with 25 ml of bulb extract in the culture medium, germination and tube growth were stimulated. Pollen tubes developed abnormally at higher concentrations.

Open Access

Abstract

Freshly dehisced pollen of Allium cepa L. was stored under various conditions of temperature and relative humidity for up to 198 days. One series of treatments was freeze dried before storage. The degree of viability was determined by germination percentages at periodic intervals. Germination of approximately 60% of the initial germination was maintained in pollen samples freeze dried and stored at −18° and 5% relative humidity. Without freeze drying, approximately 38% of initial germination was maintained in samples of onion pollen stored 198 days at −18° and 10% relative humidity. Pollen stored at −18° and 80% relative humidity germinated 34% of initial germination after 56 days of storage and gradually declined to 4% by 170 days.

Open Access

Fraser fir [Abies fraseri (Pursh) Poir.] and Norway spruce [Picea abies (L.) Karst.] were grown in seven vegetation management programs ranging from 100% cover of grass-dominated vegetation to bare soil on opposing north and south aspects. Concentrations of 13 nutrients were determined at three growth stages during 2 years: active terminal growth, cessation of terminal expansion, and dormancy. Aspect did not affect nutrient concentrations. Vegetation management programs bad a significant impact on nutrient concentration for both species. Nitrogen, Ca, B, Fe, and Mn concentrations during dormancy were negatively correlated with herbaceous biomass. In contrast, N during active growth and P and Mg concentrations during all stages were positively correlated with herbaceous biomass. Vegetation management only affected the seasonal trend of Mo. Seasonal trends varied by nutrient in both species.

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For most grocery stores, external quality standards require that premium mandarins be orange, unblemished, and large. Thus, for consumers to differentiate among the premium mandarins on any dimension other than price, additional positioning attributes must be evaluated. This study considered consumer preferences for price ($2.18/kg, $4.39/kg, or $15.41/kg), packaging (1.36 kg of loose fruit, 1.36-kg bag, 2.27-kg box, or 0.23-kg clamshell with peeled fruit sections), type of mandarin (clementine, satsuma, tangerine), shelf life from the day of purchase (3, 14, or 31 days), and vitamin C content (with or without a label stating high in vitamin C). A conjoint survey was conducted in four grocery stores located in Birmingham and Montgomery, Ala. In total, 289 respondents used a 7-point intention-to-buy scale to rate photographs of 16 product profiles. Six market segments were identified, based on maximal similarity of preferences within each segment and maximal differences between segments. A simulation was conducted of the effect that an introduction of peeled-and-sectioned satsumas would have on the market share and gross revenue of other mandarins. This product showed great potential, but should be offered in a product mix that includes the loose form as well. Labeling for vitamin C was preferred by all segments, but did not contribute much to the intention-to-buy rating. Awareness and recognition of satsumas needs to be addressed in promotional campaigns. The longest shelf life was the first choice of almost half the respondents.

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Freezing tolerance and the lethal freezing temperature were determined for detached leaves of avocado (Persea americana Mill.) by either electrolyte leakage or visual appearance of browning. Leaves from field-grown trees of `Gainesville', `Booth8', and `Winter Mexican' in both Gainesville and Homestead, Fla., were evaluated. All cultivars in both locations survived ice formation in their tissue. Leaf tissue had a temperature limit (lethal freeze temperature) at and below which the tissue died. The lethal freezing temperature varied from -5.1 to -9.3C, depending on time of year and location. The lethal freeze temperature for a cultivar decreased over the fall and winter as temperatures decreased. Leaves of `Booth-8' and Winter Mexican' decreased 2.5 and 1.5C, respectively, in Homestead from 13 Nov. 1982 to 5 Feb. 1983. The plants growing at the lower temperature location (Gainesville) had lower lethal freeze temperatures. Leaves of `Gainesville' had a lethal freeze temperature of - 9.3C from trees at Gainesville and - 7.8C from trees at Homestead.

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This article reviews the results of 5 years of marketing research on Alabama satsumas and makes recommendations for future progress. Although there are only 28 ha of satsuma orchards in production in Alabama at this time, there are a number of encouraging developments that suggest considerable potential for expanding the industry such as microsprinkler freeze protection, new early-maturing and cold-tolerant varieties, contract sales through the Farm-to-School Program, and rising demand for premium mandarins. Prospects for the industry marketing effort are considered from the perspectives of analyzing marketing opportunities, identifying market segments, selecting attractive target markets, designing marketing strategies, planning marketing programs, and managing the continuing marketing effort. A number of distinct consumer segments have been identified, including one that prefers fruit that is still slightly green and another that prefers a longer shelf life. A peeled-and-sectioned product also appears to have considerable market potential. Name recognition is still a problem as is insipid flavor from fruit that is marketed beyond its optimal ripeness. Needs for the future are detailed and include the needs of the commodity (freeze protection and expanded acreage), the needs of the market (consistency and quality), the needs of the product (quality standards and consumer awareness), the need for and the needs of a brand (recognition and equity potential), the needs of an organization (cooperation and leadership), and the needs of the industry (processes for building equity, forestalling competition, reducing supply shocks, and attracting investment).

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Annual-hill strawberry (Fragaria ×ananassa Duch.) production with black plastic mulch and drip irrigation is gaining popularity in North Carolina. Two experiments (E1 and E2) were conducted on a Wagram loamy sand (Arenic Kandiudult) in 1992 and on a Norfolk sandy loam (Typic Kandiudult) in 1993 to investigate the effects of fall-applied N and spring-applied N and K on `Chandler' strawberry yield and fruit quality. E1 treatments included factorial combinations of banded fall-applied N (0, 34, and 67 kg·ha-1) and drip spring-applied N (0, 0.19, 0.37, 0.56, and 0.75 kg·ha-1·d-1 and 0, 0.37, 0.75, and 1.12 kg·ha-1·d-1 in 1992 and 1993, respectively). E2 treatments included combinations of drip spring-applied N (0.56, 1.12, 1.68, and 2.24 kg·ha-1·d-1) and K (0.46, 1.39, and 2.32 kg·ha-1·d-1 and 0, 0.75, 1.49, and 2.24 kg·ha-1·d-1 in 1992 and 1993, respectively). There were no significant interactions among main effects for any of the measured variables. Market yield maximized with total N at ≈120 kg·ha-1 with one-half banded in the fall and the remainder drip-applied in the spring. Fruit firmness decreased with increasing N rate. Fruit pH and concentrations of total acids and soluble solids were not affected by N treatments, but soluble solids increased as the harvest season progressed. Plant crown number was not affected by N treatment but crown yield increased with N rate similar to market yield. There was no response to drip-applied K for any variable in either year. Based on soil test, fall-applied K (broadcast-soil incorporated) met the K requirements both years.

Free access

Abstract

‘Tahiti’ (Citrus latifolia Tan.) lime fruit varying in turgor, estimated by fruit water potential and rind oil release pressure, were collected and assayed for susceptibility to stylar-end breakdown. Susceptibility was determined by heating fruit for 3 hours at 42°C in a constant temperature water bath. Incidence of stylar-end breakdown was about 40% in the most turgid fruit, water potential ≥–4 bars and rind oil release pressure ≤2.0 kg. Decreasing turgor resulted in a linear decrease in susceptibility. Minimum susceptibility of from 0% to 2% was found in limes with water potential ≤–11 bars and rind oil release pressure ≥4.5 kg. Stylar-end breakdown can be controlled by maintaining strict picking schedules so that fruit are not allowed to get too large, controlling postharvest field heat, and harvesting fruit with reduced turgor pressure.

Open Access