Total Marketable Fruit Weight Research Articles

Selection of watermelon starting material by adaptability for breeding for suitability for intensive and organic growing technologies

Purpose and Objectives. To select watermelon starting materials by major productive indicators (yield, average marketable fruit weight) for the breeding of genotypes suitable for intensive and organic cultivation technologies.
 Materials and Methods. Collection watermelon accessions were studied: 101 cultivars and lines from 9 countries. Cv. ‘Maks Plus’ (Ukraine) was taken as the control accession. The following parameters were determined: Sgi – genotype’s stability, bi – regression coefficient of the genotype's response to changing conditions (plasticity), GBVi – genotype’s breeding value. Plants were grown by traditional technology in the Forest-Steppe of Ukraine (DSTU 3805-98, 1998; DSTU 5045:2008, 2008). Watermelon plants were fertilized and protected in compliance with scientific and practical recommendations. The study was conducted in accordance with routine methods of breeding. Kilchevskiy & Khotylyova’s method, 1997 was used to estimate the genotypes’ stability parameters. The coefficient of environmental plasticity (bi) was calculated by Eberhart & Russel algorithm, 1966. Data were statistically and mathematically processed in Statistica 6.
 Results and Discussion. The adaptive potential of the watermelon collection was evaluated for the following characteristics: total and marketable yields and average marketable fruit weight. The following parameters were determined: bi - coefficient of regression of the genotype’s response to changes in conditions (plasticity), Sgi – genotype’s stability, and GBVi – genotype’s breeding value of the watermelon collection. We established the amplitudes and ranges of variation of the yield indicators. By the coefficient of environmental plasticity bi, the collection watermelon accessions were grouped as showing low, medium or high environmental plasticity for different traits. The collection accessions were categorized as follows: 1 - intensive genotypes with enhanced responses to growing conditions; 2 - with medium environmental plasticity; 3 - highly plastic, which slightly respond to changes in growing conditions. For breeding for various traits, we identified accessions of practical value in terms of stability parameters and genotype’s breeding value (GBVi) for intensive and organic cultivation technologies. Taking into account the environmental variability parameters in collection watermelon accessions to be used in the breeding of cultivars and hybrids suitable for intensive technologies, we selected accessions with enhanced responses to changing growing conditions, which also consistently yielded sufficiently high. As to the yield constituents (productive traits), 5 breeding-valuable accessions were selected by the "total yield" trait, 6 – by the "marketable yield" trait, and 1 – by the "average fruit weight" trait. Analysis of the environmental variability parameters in the watermelon collection to be used as starting materials in the breeding of genotypes suitable for organic cultivation enabled us to select a number of accessions by productive traits: 6 breeding-valuable accessions were distinguished due to the "total yield" trait, 4 – due to the "marketable yield" trait, and 6 - due to the "average fruit weight" trait. The selected accessions optimally responded to year’s conditions and were relatively stable in terms of high levels of expression of these traits under in changing growing conditions.
 Conclusions. For the breeding of genotypes suitable for intensive technologies, accessions with enhanced responses to changing growing conditions were selected; at the same time, they maintained a sufficiently high stability of yields. The breeding-valuable accessions were selected by yield constituents: 5 - by the "total yield" trait; 6 – by the "marketable yield" trait; and 1 – by the "average fruit weight" trait.
 Analysis of the environmental variability parameters in the watermelon collection to be used as starting materials in the breeding of genotypes suitable for organic cultivation enabled us to select a number of accessions: 6 – by the "total yield" trait; 4 – by the "marketable yield" trait; and 6 - by the characteristic "average fruit weight" trait. The selected accessions optimally responded to changing conditions of cultivation and showed relatively stable and strong expression of these traits.

Configuration of Strawberry Yield, Nutritional and Functional Traits in Response to LPE Application in a Two-Year Study

Lysophosphatidylethanolamine (LPE) is a promising natural lysophospholipid which can be employed as a growth regulator for horticultural purposes. The present research was accomplished to investigate the effects of LPE (0 or 10 ppm) on the yield and quality of “Savana” strawberry plants grown during two consecutive cultivation cycles (I (2020–2021); II (2021–2022)). Plants cultivated in year I and treated with LPE revealed the highest total yield (838.3 g plant−1), marketable yield (735.4 g plant−1) and average marketable fruit weight (39.8 g plant−1). Fruits from year II plants treated with LPE had the highest total phenolics concentration (491.4 mg 100 g−1 dw). LPE significantly enhanced strawberry antioxidant activity, firmness, soluble solids content, ascorbic acid and anthocyanins by 5.2%, 7.6%, 15.3%, 13.8% and 19.7%, respectively, compared with the control. Although LPE application significantly reduced fruit dry matter, yellowness and lightness by 7.2%, 30.1% and 14.6%, respectively, it significantly increased, in year II, anthocyanins, discarded production, fruit lightness and dry matter. Overall, our findings also revealed that, even under sub-optimal growing conditions (year II), LPE application increased important productive and qualitative strawberry parameters.

Adaptive potential of a watermelon collection for performance indicators

Purpose and Objectives. To select highly adaptable watermelon starting material by the main indicators of the performance (yield and average marketable fruit weight).
 Materials and Methods. The watermelon collection was investigated: 101 cultivars and lines from 9 countries (55 accessions from Ukraine, 23 - from Russia, 8 - from China, 5 - from the USA, 3 - from Moldova, 2 - from Kazakhstan, Thailand and the Czech Republic each, and 1 - from Italy). A Ukrainian cultivar, Maks Plus, was taken as the check accession. The following parameters were calculated: Vi - general adaptive capacity (GAC), σ2SACi - specific adaptive capacity (SAC), Sgi - genotype stability, bi - regression coefficient of the genotype's response to changing conditions (plasticity), and GBVi – genotype breeding value. AV Kilchevskyi and LV Khotylyova’s method was applied to estimate the parameters of adaptive capacity and stability of the genotypes. The environmental plasticity coefficients (bi) were calculated according to SA Eberhart and WA Russel algorithm. Data were statistically processed, as BA Dospekhov recommended.
 Results and Discussion. The adaptive potential of the watermelon collection was evaluated for the following traits: total yield, marketable yield, and average marketable fruit weight. The variation amplitude (Am) of the "total yield" trait based on the averaged three-year data on the collection was 51.26; the variation range was 15.07 - 66.33 t/ha. In the check accession, Maks Plus, the mean total yield across the 3 years was 64.72 t/ha. For further work, we selected 31 collection accessions, basing on the total yield” trait. The adaptability parameters of the collection watermelon accessions for the "marketable yield" trait differed somewhat from those for the “total yield” trait. From the averaged three-year data, the variation amplitude (Am) of the "marketable yield" trait was 51.15 t/ha; the variation range of this trait was 13.19 - 64.34 t/ha. The variation amplitude of the "average marketable fruit weight" trait based on the averaged three-year data was 3.00 kg. The variation range of this trait was 0.99–3.99 kg. The average fruit weight in the sample across the 3 years was 2.14 kg. In the check cultivar, Maks Plus, the average fruit weight was 2.50 kg. For the breeding for the characteristics under investigation, accessions of practical value, with high values of the general adaptive capacity, stability, and genotype breeding value were selected. By the environmental plasticity coefficient bi, the collection watermelon accessions were categorized as low-, mid- and highly plastic in terms of the characteristics under investigation: intensive accessions with enhanced responses to growing conditions, accessions with moderate levels of the environmental plasticity, and highly plastic accessions, which slightly respond to changes in growing conditions.

Heat stress mitigation effects of kaolin and s-abscisic acid during the establishment of strawberry plug transplants

In Florida, early planting to take advantage of higher prices for early fruit has been proposed for the strawberry (Fragaria ×ananassa Duch.) industry, but it can expose strawberry transplants to heat stress which is common in sub-tropical conditions. Additionally, strawberry plug transplants are of interest for addressing the high sprinkler irrigation requirement for bare-root transplant establishment. The objective of this study was to examine the effectiveness of antitranspirants, s-abscisic acid (s-ABA) and kaolin, in heat stress mitigation for strawberry plug transplants. Trials were conducted in Citra, Florida during three seasons (2015–2016, 2016–2017, and 2017–2018). The s-ABA was applied as a root dip just prior to transplanting. In 2015–2016, s-ABA was applied at 250, 500, 750, and 1000 mg L−1. Lower rates of 50–250 mg L−1 were used during the subsequent years. Kaolin was applied at 56 kg·ha−1 as either a single foliar spray immediately after transplanting or as two consecutive sprays seven days apart. Transient stomatal closure with ≤ 100 mg L−1 of s-ABA provided protection from heat stress with little or no negative side effects and resulted in higher early and total season yields than the untreated control. Both the single and double applications of kaolin consistently protected strawberry transplants from heat stress, enhancing photosynthesis as well as early and total marketable fruit weight. Since the double application of kaolin provided higher early marketable fruit weight than the single kaolin application, the double applications of kaolin appear to have better potential than the single application for mitigating heat stress in sub-tropical conditions during strawberry plug transplant establishment.

Correlation & path analysis in local germplasm and characters association of ivy gourd (Coccinia grandis L.)

The experiment was carried out with 30 genotypes in completely randomized block design with 3 replications to study the association among fruit weight and its components and their direct and indirect influence on total marketable fruit weight of ivy gourd at Department of Horticulture, Rajasthan College of Agriculture, Maharana Pratap University of Agriculture and Technology, Udaipur during kharif season 2017–18 in completely randomized design with three replications. Correlations study revealed that phenotypic correlation coefficient was slightly higher than corresponding value of genotypic correlation for majority of the characters. Fruit weight has highest significant positive correlation with total chlorophyll and significant negative correlation with fruit volume. The correlation between phosphorus and fruit diameter was negative significant. Path analysis study revealed that average leaf length has showed highest positive direct effect on fruit weight followed by total chlorophyll content in leaves, petiole length, ascorbic acid content whereas, moisture, inter nodal length, fruit length, leaf width showed negative direct effect on the fruit weight.

Comparison of Freeze Protection Methods for Strawberry Production in Florida

During strawberry (Fragaria × ananassa) freeze protection, the standard practice is applying sprinkler irrigation on plant canopies to prevent and reduce freezing damage. This method is highly inefficient because it uses large volumes of water. The overall goal of this study was to compare the effects of freeze protection methods on water savings, and growth and fruit weight of strawberry. Treatments consisted of the following: sprinkler heads delivering 17 L∙min–1, sprinkler heads delivering 13 L∙min–1, light-weight row covers (21 g∙m–2) on the crop canopy, light-weight row covers on 60-cm-high mini-tunnel hoops, heavy-weight row covers (31 g∙m–2) on the crop canopy, heavy-weight row covers on 60-cm-high mini-tunnel hoops, and foliar application of a polymer (Desikote). There were eight freezing and near freezing nights (≤1.1 °C) at the experimental site during both seasons with a minimum air temperature of –2.8 °C. Minimum temperature inside the row covers ranged between 0.6 to 4.4 °C at the canopy level. There were significant treatment effects on early and total marketable fruit weights. The highest early marketable fruit weight was found in plots protected with light-weight row covers with hoops, heavy-weight row covers on canopy, and foliar polymer, ranging between 5.0 to 5.5 t∙ha–1. For total marketable fruit weight, using non-irrigation methods resulted in the highest fruit weight with 23.0 t∙ha–1. In conclusion, data showed that using non-irrigation techniques provided satisfactory freeze protection under the evaluated conditions and increased total marketable fruit weight, possibly due to reduced injury of fruits and flowers when using alternative techniques.

Soilless Media and Containers for Bell Pepper Production

Bell pepper (Capsicum annuum Mill.) production in protected culture improves fruit quality and yield. Under this system, bell pepper is typically grown in soilless culture to reduce problems associated with poor physical soil properties and soilborne diseases. However, cost, variability, and growing conditions are often criteria for choosing a specific substrate. It is important to understand the physical and chemical properties of media that influence crop yield and fruit quality. The goal of this project was to determine responses of bell pepper plants grown in box, bag, and pot containers and coconut coir, pine bark, and potting mix soilless media in a 50-mesh nethouse. Media chemical and physical analysis, plant height, total marketable yield, and root dry biomass were determined. The combination of potting mix with bags, pots, or boxes increased bell pepper total marketable fruit weight, number, and plant height compared to pine bark and coconut coir.

Effects of Preplant Potassium Sources and Rates for Tomato Production

A two-season study was conducted to assess the effects of preplant potassium (K) fertilization rates and sources on the growth and yield of beefsteak tomato (Solanum lycopersicum). Fourteen treatments resulted from the combination of two K sources: sulfate of potash [SOP (0N–0P–42K)] and muriate of potash [MOP (potassium chloride, 0N–0P–50K)] and seven preplant K rates (0, 50, 100, 200, 300, 400, and 500 lb/acre). Soil electrical conductivity (EC) at 4 weeks after transplanting was influenced by the interaction between preplant K rates and sources. When SOP was applied, soil EC increased from 0.4 dS·m−1 with no preplant K application to ≈1.3 dS·m−1 with a rate of 500 lb/acre of preplant K. However, the soil EC steadily increased from 0.4 to 3.0 dS·m−1 as preplant K rates increased from 0 to 500 lb/acre when MOP was used as the nutrient source. The combined effect of the preplant application of K rates and sources influenced the seasonal extra-large and total marketable fruit weight, which increased steadily with K rates, regardless of the sources, from 0 to 300 lb/acre. At K rates between 300 and 500 lb/acre, there were no extra-large and total fruit weight differences among rates when SOP was applied. In contrast, extra-large and total marketable fruit weight declined when rates increased from 300 to 500 lb/acre of K and MOP was applied to the soil. Data demonstrated that plots treated with MOP at rates higher than 300 lb/acre of K increased soil EC and caused a decline on extra-large and total marketable fruit weight of tomato.

Irrigation, Mulches, and Fumigants on Tomato Performance in Sandy Soils

Current best management practice programs in Florida aim to reduce water volumes needed for producing vegetable crops. Therefore, irrigation practices that save water while maintaining the economic sustainability of those crops are desirable. Field studies were conducted to determine the effects of water management regimes on tomato (Solanum lycopersicum L.) production and assess the effects of highly retentive mulches and methyl bromide alternatives on water volumes necessary for tomato irrigation. Twelve treatments resulted from combinations of fumigant, mulches, and irrigation programs. The combinations of fumigants and mulches were as follows: a) methyl bromide + chloropicrin (67:33 v/v) at a rate of 196 kg·ha−1 under metalized mulch; b) 1,3-dichloropropene + chloropicrin (65:35 v/v) at 150 L·ha−1 under metalized mulch; and c) 1,3-dichloropropene + chloropicrin (65:35 v/v) at 300 L·ha−1 under high-density polyethylene mulch. Irrigation methods were seepage (subsurface) irrigation alone at 5000 and 10,000 m3/ha per season and the same seepage irrigation volumes combined with a drip irrigation volume of 3500 m3/ha per season. Increasing seepage volume from 5000 and 10,000 m3/ha in combination with drip irrigation did not increase average soil moisture, which ranged from 9.0% to 10.3%. Irrigation volumes affected soil moisture when only seepage irrigation was provided, with values increasing from 9.4% to 11.9% when water volumes increased from 5000 to 10,000 m3/ha, respectively. Only irrigation affected total marketable fruit weight. Adding drip irrigation to seepage-treated plots positively affected fruit weight, increasing yields from 36.5 Mg·ha−1 in plots with only seepage to 39.5 Mg·ha−1. Increasing seepage irrigation from 5000 to 10,000 m3/ha in plots under drip irrigation improved yield from 34.5 to 44.5 Mg·ha−1. However, increasing seepage volumes in plots without drip irrigation did not affect tomato total marketable yields.

Response of Strawberries to Preplant Sulfur Fertilization in Sandy Soils

The response of strawberry (Fragaria × ananassa) to different rates of preplant sulfur (S) fertilization was assessed in two studies in Florida. The preplant S rates were 0, 25, 50, 125, 200, and 275 lb/acre and elemental S was used as the nutrient source. Preplant S application did not affect plant canopy diameters or shoot dry biomass. However, leaf greenness increased with preplant S. The foliar concentrations of S and magnesium (Mg) also increased when the S rate reached 50 lb/acre, whereas the application of S rates of 125 lb/acre or higher increased the concentration of manganese (Mn) in the leaves. Total marketable fruit weight increased by 10% with 50 lb/acre of S in comparison with the non-treated control. There were no further yield increases with S rates higher than 50 lb/acre. Preplant S rates higher than 50 lb/acre did not improve strawberry marketable fruit weight. A similar response was found for strawberry root dry biomass at the end of the season.

Heirloom Tomato Production in Conventional and Transitional-organic Managed Systems

Demand for heirloom tomatoes (Solanum lycopersicum L.) and organically grown produce is increasing. The objective of this research was to compare heirloom tomato production in conventional (CS) and organic-transitional (OS) production systems. Heirloom cultivars Arkansas Traveler–the original, Cherokee Purple, Kentucky Beefsteak, Manulucie, and Persimmon Orange were grown in 2007 and 2008 on a raised bed, microirrigated, black plastic mulch culture in a split-plot design with production system as the main plot. Inorganic fertilizer at 160N–13P–50K kg·ha−1 [NH4NO3, Ca(H2PO4)2, KCl] or poultry litter (PL) at 5600 kg·ha−1 was applied in March and soil-incorporated. Transplanting occurred on 12 Apr. 2007 and 22 Apr. 2008. PL supplied 194N–133P–183K and 145N–83P–171K kg·ha−1 potential in 2007 and 2008, respectively. Overall, there were no system effects on total marketable fruit weight, marketable fruit numbers, average fruit weights, total cull weights, or percent marketable yields. Marketable yields averaged across systems ranged from 8,457 to 13,550 kg·ha−1 in 2007 and 1,224 to 5,974 kg·ha−1 in 2008. Weather-delayed transplanting followed by wet and cloudy weather in April and May and greater incidence of tomato spotted wilt virus (TSWV) were suspected for lower yields in 2008. Petiole sap nitrate-N of whole plot treatments were considered within sufficiency levels for both systems when checked at pre- and early harvest. Soil pH of the CS dropped from 7.2 to 5.6 after two seasons but did not change in the OS. Organic production of heirloom tomatoes using PL yielded equivalently to conventional culture for 2 years after transition from conventional management.

Inheritance of fruit yield in two watermelon populations in North Carolina

Elite cultivars of watermelon (Citrullus lanatus (Thunb.) Matsum. & Nakai) are high in fruit quality but may not be the highest yielders. The objective of this study was to estimate the heritability of, and genotypic and phenotypic correlations among, yield traits in two watermelon populations developed from crosses between obsolete cultivars with high yield and elite modern cultivars. Field trials were conducted at two locations in North Carolina (Clinton and Kinston). The data were analyzed by regressing S0:1 progeny data on S0 parent data to estimate narrow-sense heritability. Narrow-sense heritability estimates were low for all traits measured [total fruit weight (0.04–0.12), marketable fruit weight (0.06–0.15), total fruit number (0.04–0.16), fruit size (0.18–0.19), and percent culls (0.02–0.09) in North Carolina Watermelon 1 (NCWP1) and North Carolina Watermelon 2 (NCWP2) populations, respectively]. Estimates of broad-sense heritability were higher than estimates of narrow-sense heritability. Total fruit weight and marketable fruit weight were highly correlated (rg = 0.97–1.00). Marketable fruit weight and fruit size used as single selection criteria in NCWP1 and total fruit number in NCWP2, were predicted to give the best correlated response for total fruit weight. Narrow-sense heritability was low for fruit yield; therefore, watermelon breeders should select based on replicated progeny rows in multiple environments to maximize gain.

Influence of Nitrogen Fertilization Rates on the Performance of Strawberry Cultivars

Two sets of studies were conducted to examine the response of “Strawberry Festival” and “Winter Dawn” strawberries (Fragaria x ananassa Duch.) to different nitrogen (N) rates. The first set of studies consisted of two trials conducted during the 2005–06 and 2006–07 growing seasons. N rates were 0.5, 0.7, and 0.9 kg/ha per day (75, 105, and 135 kg/ha per season). The second set of studies was conducted during the 2006–07 and 2007–08 growing seasons. Nitrogen rates were 0.9, 1.4, and 2.0 kg/ha per day (75, 210, and 300 kg/ha per season) using the same cultivars. During the first set of studies, canopies of “Strawberry Festival” were 30% and 10% wider than “Winter Dawn” at 6 and 12 weeks, whereas N rates linearly increased canopy diameters of both cultivars. There was a significant cultivar by N rate interaction for total marketable fruit weight. Increasing N rates from 0.5 to 0.9 kg/ha per day linearly improved total marketable fruit weights of “Strawberry Festival,” but not those of “Winter Dawn.” For the second set of studies, N rates only influenced strawberry plant canopy diameters, but not early and total marketable fruit weight and number. There were no differences between the total marketable fruit weights of both cultivars. The data showed that the response of different strawberry cultivars depends on the range of N rates used for fertilization.

Influence of Cultivar, Growing Media, and Cluster Pruning on Greenhouse Tomato Yield and Fruit Quality

Cultivars and growing media are important components of a successful greenhouse tomato (Solanum lycopersicum) operation. Two studies were conducted simultaneously and independently in two 30 × 96-ft greenhouses in Spring 2006 and 2007 (January–July) to assist producers in selecting appropriate cultivars and reducing production cost. The first study was conducted to evaluate yield, fruit weight, fruit quality, and shelf life of ‘Geronimo’, ‘Quest’, and ‘Trust’ tomatoes planted in perlite and pruned to three or four fruit per cluster. The second study was conducted to determine the initial cost of perlite, pine bark, and rockwool growing media and their effect on yield of ‘Quest’ pruned to three or four fruit per cluster. ‘Geronimo’ produced the highest total marketable yield and ‘Trust’ produced the lowest. ‘Trust’ produced more cull yield and lower fruit weight than ‘Geronimo’ or ‘Quest’. Pruning clusters to three fruit increased total marketable yield and fruit weight, and reduced cull yield of all cultivars. Only ‘Geronimo’ produced higher early marketable yield at four fruit per cluster. All cultivars produced higher early marketable yield in 2007 than in 2006. Tested cultivars had similar fruit content of potassium and sodium and similar concentration of soluble solids. ‘Trust’ fruit had a higher pH than the other two cultivars. About 92% of ‘Quest’ tomatoes remained marketable after storage at 67 °F for 1 week. ‘Geronimo’ and ‘Trust’ had only 83% and 78% marketable fruit, respectively, under the same conditions. Initial costs to grow greenhouse tomatoes in perlite were higher than in rockwool, and were the lowest in pine bark. Plants grown in perlite produced higher total marketable yield than plants grown in either of the other media. They produced lower cull yield than plants grown in rockwool, but produced similar cull yield to plants grown in pine bark. Pruning clusters to three fruit increased total marketable yield and fruit weight in both studies. Pruning clusters to four fruit increased cull yield in both studies regardless of planting year.

Influence of Cultivar, Growing Media, and Cluster Pruning on Greenhouse Tomato Yield and Fruit Quality

Cultivars and growing media are important components of a successful greenhouse tomato (Solanum lycopersicum) operation. Two studies were conducted simultaneously and independently in two 30 × 96-ft greenhouses in Spring 2006 and 2007 (January–July) to assist producers in selecting appropriate cultivars and reducing production cost. The first study was conducted to evaluate yield, fruit weight, fruit quality, and shelf life of ‘Geronimo’, ‘Quest’, and ‘Trust’ tomatoes planted in perlite and pruned to three or four fruit per cluster. The second study was conducted to determine the initial cost of perlite, pine bark, and rockwool growing media and their effect on yield of ‘Quest’ pruned to three or four fruit per cluster. ‘Geronimo’ produced the highest total marketable yield and ‘Trust’ produced the lowest. ‘Trust’ produced more cull yield and lower fruit weight than ‘Geronimo’ or ‘Quest’. Pruning clusters to three fruit increased total marketable yield and fruit weight, and reduced cull yield of all cultivars. Only ‘Geronimo’ produced higher early marketable yield at four fruit per cluster. All cultivars produced higher early marketable yield in 2007 than in 2006. Tested cultivars had similar fruit content of potassium and sodium and similar concentration of soluble solids. ‘Trust’ fruit had a higher pH than the other two cultivars. About 92% of ‘Quest’ tomatoes remained marketable after storage at 67 °F for 1 week. ‘Geronimo’ and ‘Trust’ had only 83% and 78% marketable fruit, respectively, under the same conditions. Initial costs to grow greenhouse tomatoes in perlite were higher than in rockwool, and were the lowest in pine bark. Plants grown in perlite produced higher total marketable yield than plants grown in either of the other media. They produced lower cull yield than plants grown in rockwool, but produced similar cull yield to plants grown in pine bark. Pruning clusters to three fruit increased total marketable yield and fruit weight in both studies. Pruning clusters to four fruit increased cull yield in both studies regardless of planting year.

Combinations of Nitrogen Rates and Irrigation Programs for Tomato Production in Spodosols

Two field studies were conducted to compare the effects of preplant nitrogen (N) rates and irrigation programs on tomato (Solanum lycopersicum) growth and yields. Irrigation programs were seepage (subsurface) irrigation alone at a water volume of 28 acre-inches/acre per season and seepage plus drip irrigation at a volume of 28 and 14 acre-inches/acre per season, respectively. Preplant N fertilization rates were 200, 250, and 300 lb/acre, using ammonium nitrate as the N source. There were significant irrigation program by N rate interactions for nitrate (NO3−) petiole concentrations at 8 weeks after transplanting (WAT), and yield of extra-large fruit and total marketable fruit, but not for plant height at 5 and 7 WAT. The highest NO3-N petiole concentrations were found in plots treated with 200, 250, and 300 lb/acre for N and seepage plus drip irrigation, and with 300 lb/acre N under seepage irrigation alone. For the total marketable fruit weight, there were no differences among N rates in those plots irrigated with the seepage plus drip combination, ranging between 23.8 and 25.9 tons/acre. However, there was a significant N effect in plots receiving only seepage irrigation with marketable fruit weight almost doubling from 12.0 to 22.7 tons/acre when applying 200 and 300 lb/acre N, respectively. Both irrigation programs had equivalent performance when 300 lb/acre N were applied.

Combinations of Nitrogen Rates and Irrigation Programs for Tomato Production in Spodosols

Two field studies were conducted to compare the effects of preplant nitrogen (N) rates and irrigation programs on tomato (Solanum lycopersicum) growth and yields. Irrigation programs were seepage (subsurface) irrigation alone at a water volume of 28 acre-inches/acre per season and seepage plus drip irrigation at a volume of 28 and 14 acre-inches/acre per season, respectively. Preplant N fertilization rates were 200, 250, and 300 lb/acre, using ammonium nitrate as the N source. There were significant irrigation program by N rate interactions for nitrate (NO3−) petiole concentrations at 8 weeks after transplanting (WAT), and yield of extra-large fruit and total marketable fruit, but not for plant height at 5 and 7 WAT. The highest NO3-N petiole concentrations were found in plots treated with 200, 250, and 300 lb/acre for N and seepage plus drip irrigation, and with 300 lb/acre N under seepage irrigation alone. For the total marketable fruit weight, there were no differences among N rates in those plots irrigated with the seepage plus drip combination, ranging between 23.8 and 25.9 tons/acre. However, there was a significant N effect in plots receiving only seepage irrigation with marketable fruit weight almost doubling from 12.0 to 22.7 tons/acre when applying 200 and 300 lb/acre N, respectively. Both irrigation programs had equivalent performance when 300 lb/acre N were applied.

Cultivar and Plant Arrangement Effects on Yield and Fruit Quality of Bell Pepper

Single- and double-row arrangements of a fixed population (one plant every 0.285 m2) were compared in factorial combination with two (2002) or five (2003) cultivars for effects on yield and fruit quality of bell pepper (Capsicum annuum L.). Arrangements for 2002 were S30, single rows 0.95 m apart, plants within rows 30 cm apart; D30, 1.9 m between centers of double-row beds, double rows 30 cm apart on beds, plants within rows 30 cm apart; S37.5, single rows 0.76 m apart, plants within rows 37.5 cm apart; and D37.5, 1.52 m between centers of double-row beds, double rows 24 cm apart on beds, plants within rows 37.5 cm apart. Only the S30 and D30 arrangements were used in 2003 after 2002 results showed almost no differences between S30 and S37.5 or between D30 and D37.5. Choice of cultivar was more critical in Texas, where `X3R Wizard' consistently outperformed `King Arthur', than in Oklahoma. Single rows resulted in more full-season total marketable fruit weight than double rows in three experiments out of four, primarily as a result of an increased weight of U.S. No. 1 fruit with single rows. Average weight per marketable fruit was consistently unaffected by plant arrangement. Single rows also resulted in a greater full-season weight of sunburned fruit than double rows in two experiments out of four. Cultivar × plant arrangement interactions were not evident in Oklahoma and never involved full-season marketable fruit weights at either location in either year. Given the tested population, a single-row arrangement is likely to result in increased full-season production of U.S. No. 1 bell pepper fruit compared with a double-row arrangement, despite an increased potential for sunburned fruit with single rows.

Performance of Containerized and Bare-root Transplants with Soil Fumigants for Florida Strawberry Production

Field studies were conducted in three Florida locations (Bradenton, Gainesville, and Quincy) during 1998-99 and 1999-2000 to: 1) compare the performance of two transplant systems under diverse MBr alternative programs in `Chandler' strawberry (Fragaria ×ananassa), and 2) determine the efficacy of these treatments on soilborne pest control in strawberry. Fumigant treatments were: 1) nonfumigated control, 2) methyl bromide plus chloropicrin (MBr + Pic) at a rate of 350 lb/acre, 3) Pic at 300 lb/acre and napropamide at 4 lb/acre, 4) 1,3-dichloropropene (1,3-D) plus Pic at 35 gal/acre and napropamide at 4 lb/acre, 5) metam sodium (MNa) at 60 gal/acre and napropamide at 4 lb/acre, and 6) MNa followed by 1,3-D at 60 and 12 gal/acre and napropamide at 4 lb/acre, respectively. Strawberry transplants were either bare-root or containerized plugs. There were no significant fumigant by transplant type interactions for strawberry plant vigor and root weight per plant, whereas ring nematode (Criconema spp.) and nutsedge (Cyperus rotundus and C. esculentus) populations, and total marketable fruit weight were only infl uenced by fumigant application. The nonfumigated plots had the lowest strawberry plant vigor and root weight per plant in all three locations. In most cases, plant vigor and root biomass per plant increased as a response to any fumigant application. With regard to the transplant type, bare-root transplants had similar plant vigor as plugs in two of the three locations. Fumigation improved nutsedge and ring nematode control. All fumigants had higher early and total marketable yield than the nonfumigated control, whereas transplant type had no effect on total fruit weight.

A Ratoon Cropping System for Fall Bell Pepper Production

Studies were conducted to examine the effects of pruning treatments applied to spring-transplanted bell peppers (Capsicum annuum L.) on marketable fruit yield in late summer and fall. Control plants were set in the field in early May 1997 (Oklahoma) and Apr. 1998 (Oklahoma and Texas) and harvested weekly into October (Oklahoma) or periodically into December (Texas). In 1997, all four treatments (involving height and method of pruning) reduced total marketable fruit weight, but differences among treatments were nonsignificant. In Oklahoma in 1998, plants were mowed on 27 July at an average height of ≈24 cm. Mowed plants produced less total marketable fruit weight but more U.S. Fancy fruit than did control plants, while weight of U.S. No. 1 fruit was not affected. In Texas in 1998, plants mowed on 4 Sept. at a height of ≈20 cm produced more than twice the weight of U.S. No. 1 fruit and fewer cull fruit than did control plants. Nonpruned transplants set in the field in Summer 1998 (both Oklahoma and Texas) produced low marketable yields. Maintaining spring-transplanted bell peppers is a viable technique for fall pepper production, and the highest total marketable yields may be obtained if these plants are not mowed. However, mowing offers an opportunity for increased fall production of premium fruit, and mowed plants would be easier to manage than nonpruned plants.