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  • Author or Editor: Darbie Granberry x
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During summer in southern Georgia, greenhouses often reach or exceed 49C. Subsequently, transplants grown in these houses tend to exceed optimum height. To determine effects of N and P fertility levels on pepper (Capsicum annuum) transplant growth, applications of nutrient solutions with 58, 12, and 0 ppm N and 114, 57, and 0 ppm P205

were applied to recently emerged Capistrano bell pepper beginning 12 Aug. 1994. Plants were grown in polystyrene flats using a commercial noncharged artificial soil mix. Nutrient solutions were applied as needed to maintain adequate moisture until 31 Aug., except for two treatments that received only water after 22 Aug. Data were taken on 22 and 31 Aug. With 58 ppm N, 0 P decreased plant height, leaf count, leaf area, and plant weight. Higher N increased plant height, ratings of intact root plugs and washed roots, stem diameter, leaf count, leaf area, and plant weight. At 12 ppm N, P had no significant effect on transplant growth. Withholding fertilizer the final week reduced plant height, ratings of intact root plugs, stem diameter, number of leaves, leaf area, and plant weight.

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Bell pepper (Capsicum annuum) has traditionally been transplanted to the top of the root ball or to the cotyledons of the transplant. Recent studies have shown increased and earlier yields are obtained by transplanting pepper deeper. Thus, a study was initiated to investigate effects of transplanting depth on pepper yield and plant growth. Pepper was transplanted to the top of the rootball, the cotyledons, and the first true leaf in two locations in 1994. `Camelot' hybrid and `Jupiter' (open pollinated) cultivars were planted into bare ground on Mar. 24 in Tifton, Ga. Only `Camelot' was transplanted into a plastic mulch with drip irrigation on Mar. 28 in Cool Springs. Plots consisted of single rows of seven plants with data collected from the internal five plants. Treatments were replicated three times. Normal cultural and pest control practices were used at both locations. Plant measurement data were taken 5 weeks after transplanting. Yield data were collected at harvest. Total weight per plant of three harvests was significantly greater with peppers planted to cotyledons and first true leaf than those planted to the rootball in `Jupiter'. There was no significant effect of planting depth on `Camelot', although there was a distinct trend toward greater yield with deeper planting on plastic. The same trend was evident for average weight per plant and average number of fancy-grade peppers per plant. Average stem diameter, plant height, and length of largest leaf were all greater among deeper planted peppers. Deeper planting seems to have a positive effect on yield and plant growth, particularly with hybrid pepper planted into a plastic mulch.

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Abstract

Seedlings of sweet potato [Ipomoea batatas (L.)], which failed to form storage roots, produced good yields of sweet potato roots of acceptable size and grade when propagated asexually by vine cuttings.

Open Access

Tomato spotted wilt virus (TSWV) is a serious constraint to tomato production worldwide. Losses are significant because the disease is difficult to control and most of the commercially available tomato cultivars are susceptible to TSWV. This study was intended to provide information that could be used to design more appropriate disease management strategies. The objective was to determine the relationship of tomato plant growth and fruit yield with the time of TSWV symptom appearance. Experiments were carried out during Spring 1999 and 2000, using drip irrigation and plastic film mulched beds with black plastic mulch alone (1999) or different colored mulches (2000). The mulches used were black, black-on-silver, gray-on-black, red, silver-on-black, silver (painted) and white-on-black, and bare soil. The 1999 experiment included a single TSWV-susceptible cultivar (Florida-47), while the 2000-experiment included two TSWV-susceptible (Florida-91 and Sun Chaser) and one TSWV-resistant cultivars (BHN-444). Colored mulches and tomato cultivars affected the time between transplanting and appearance of first symptoms of TSWV. For all tomato cultivars, vegetative top fresh weight (FW), fruit number and total fruit yield increased linearly with the time the plants remained free from TSWV symptoms. Marketable fruit yield also increased as the time from transplanting to the first appearance of symptoms increased. When data for cultivars were pooled, vegetative top FW and total fruit yield were reduced by 2.1% and 2.3%, respectively, for each day prior to harvesting that plants showed TSWV symptoms.

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Bell pepper (Capsicum annum L.) plants have a high demand for water and nutrients and are sensitive to water stress during the establishment period and fruit setting. High levels of irrigation are often applied in order to maximize yields. However, field observations suggest that excessive irrigations may negatively affect bell pepper plants. The objective was to evaluate the effects of irrigation rate on plant growth and fruit yield. The trial was conducted in Spring 2003 at the Coastal Plain Experiment Station, Tifton, Ga. Drip-irrigated bell pepper (`Stiletto') plants were grown on black plastic mulch in 1-m wide beds (1.8-m centers). Plants were irrigated with an amount of water that ranged from 33% to 167% the rate of evapotranspiration (ET), adjusted by crop stage of development. Soil moisture content (% by volume) over the season was continuously monitored with time domain reflectometry sensors connected to a datalogger. The results showed that the average soil moisture content for the season increased with increasing rates of irrigation. Vegetative top fresh wt. and marketable fruit yield were reduced at both, low (33% ET) and high (166% ET) rates of water application. However, irrigation rate had a stronger effect on fruit yield than on top fresh wt. Plants supplied with high irrigation rates appeared to be more chlorotic compared to plants irrigated at medium rates (100% ET). There was a tendency for higher incidences of soil borne diseases (Pythium sp., Phytophtora capsici) in plants receiving higher rates of irrigation. The conclusion is high irrigation rates (>166% ET) are not recommended since they waste water and may result in both, higher incidences of soil-borne diseases and reduced bell pepper yields.

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The experiment screened two spring and two fall planting dates in six regions within North Carolina, South Carolina, and Georgia. The objective was to extend the production over the southeastern United States rather than at a single location. Spring harvests lasted from mid-April to early July. Summer-to-winter harvests lasted from mid-August to late January. Collards were not harvested in any of the locations from late January to mid-April or from early July to mid-August. More extensive planting dates may further increase the longevity of production.

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Four bell pepper (Capsicum annuum L.) cultivars were evaluated for yield (total weight of marketable fruit) performance over 41 environments as combinations of 3 years, three planting dates, and seven locations across North Carolina, South Carolina, and Georgia. Cultural practices, including trickle irrigation and double rows planted on black-plastic-covered beds, were uniform across all environments, except for fertilization, which was adjusted at each location based on soil tests. Comparing production over 3 years between the mountain location and the Coastal Plain location in North Carolina, yields were lower on the Coastal Plain. Spring plantings provided higher yields than summer plantings at both locations. Yield increases were obtained from hybrid cultivars over that of the open-pollinated (OP) standard [`Keystone Resistant Giant #3' (KRG#3)] in the summer planting in the mountains compared to the Tidewater Coastal Plain. Across the three-state region, hybrid cultivar yields were higher than those of the OP cultivar for the second spring planting date in 1986 and 1987. Although the hybrid yields were higher than that of the OP standard, the hybrid `Skipper' yielded less than the other hybrids (`Gator Belle' and `Hybelle'). `Gator Belle' generally out-yielded `Hybelle' at all locations, except in Fletcher, N.C. This difference may be related to the relative sensitivity of these two cultivars to temperature extremes, rather than soil or geographic factors, because there was a tendency for `Hybelle' yields to exceed `Gator Belle' in the earliest planting date. Based on the reliability index, the chance of outperforming KRG#3 (the standard) was 85% for `Hybelle', 80% for `Gator Belle', but only 67% for `Skipper'.

Free access

Abstract

‘Champion’, ‘Georgia’, ‘Heavicrop’, and ‘Vates’ collards (Brassica oleracea L. var acephala) were planted in Fletcher and Lewiston, N.C.; Charleston, Clemson, and Florence, S.C.; and Attapulgus and Plains, Ga. to determine the most reliable method to predict harvest maturity based on temperature. Although cultivar differences existed within some of the planting dates, when pooled over all planting dates, cultivars yielded similarly within locations. Eight methods of calculating heat units from planting to harvest were applied to daily maximum and minimum air temperatures supplied from local weather bureaus for the spring and fall growing seasons from 1985 through 1987 in the three-state area. Coefficients of variation were used to determine which method was most reliable in predicting day of first harvest. The method with the lowest cv was to sum, over days for planting to harvest, the difference between the daily maximum and a base temperature of 13.4C; however, if the maximum was >23.9C, the base temperature was subtracted from an adjusted maximum equal to 23.9C minus the difference between the maximum and 23.9C. This method produced a cv of 9.1% compared to 11.4% for the standard method of summing the mean temperature minus the base of 4.4C over the entire growing season, or compared to 13.4% for counting days to harvest from planting.

Open Access