Summer Flavor Research Articles

Production and quality of grafted watermelon in saline soil

ABSTRACT Salinity of soil in arid and semiarid regions is a problem that affects the production and quality of fruit. That’s while we evaluated grafting on watermelon plants as an alternative to reduce the salinity effects. The experimental design was of randomized blocks, three treatments (cultivars Sangria, Summer Flavor 800 and Summer Flavor 840) with three repetitions. The cultivars were evaluated in grafted and ungrafted condition. The rootstock used for grafting was the interspecific hybrid Strong Tosa (C. maxima x C. moschata). In average terms for the three cultivars, grafting increased commercial production, weight, length and diameter of fruits in 160.5%, 36.5%, 12.0% and 7.5%, respectively. Sangria presented the best answer in production with 57.1 t ha-1, weight 5.8 kg, length 35.0 cm and diameter 17.8 cm of fruits. Also, grafting favored in 6.3% the luminosity and reduced 6.4% Hue angle. Summer Flavor 840 showed the best result in luminosity with 48.3 and hue angle 26.4°. Firmness, °Brix and lycopene content were not modified by grafting. Grafting represents an alternative for watermelon production in saline soils, improving yield and quality of the fruits.

Growth Reductions by Exogenous Abscisic Acid Limit the Benefit of Height Control in Diploid and Triploid Watermelon Transplants

Height control is important to produce compact vegetable transplants that are suitable for shipping and transplanting. Although abscisic acid (ABA) inhibits stem elongation, it can also induce other growth modifications. To optimize its application timing for effective height control, we examined age-dependent sensitivity of various growth variables to ABA in diploid ‘Summer Flavor 800’ and triploid ‘Summer Sweet 5244’ watermelon [Citrullus lanatus (Thunb.) Matsum & Nakai]. Seedlings were sprayed once with 1.9 mm ABA at 25, 18, or 11 days before transplanting (DBT) or twice with 0.95 mm ABA at 25 and 18 DBT. The application rate was 0.55 mg ABA per plant with a spray volume of 0.61 L·m−2 (1.1 mL/plant). Only the single-spray treatment at 25 DBT (cotyledon stage) suppressed plant height by inhibiting petiole elongation. This effect was similar in both cultivars with 13% to 14% reductions at the transplanting stage compared with the untreated control. Undesirable growth modifications were also induced by ABA. In both cultivars, all ABA treatments caused 16% to 23% shoot biomass reductions mainly by inhibiting leaf expansion. Additionally, ABA treatments reduced stem diameter and root biomass in ‘Summer Flavor 800’. The double-spray treatment had similar growth-modulating effects as the single-spray treatments, except that it induced cotyledon abscission in ‘Summer Flavor 800’. These results suggest that although ABA applied at the cotyledon stage can reduce watermelon transplant height, the benefit is limited because of overall growth reductions, which can occur regardless of application timing. On the other hand, in triploid ‘Summer Sweet 5244’, moderate shoot growth delay by ABA may be of value as a growth-holding strategy when transplanting is delayed because of inclement weather at the time of field establishment. Importantly, field evaluations demonstrated that the growth modulation by ABA is only transient with no negative impact on marketable yield and fruit quality.

Use of Commercially Available Pollenizers for Optimizing Triploid Watermelon Production

An experiment was conducted during 2005 and 2006 in Kinston, NC, with the objective of maximizing triploid watermelon [Citrullus lanatus (Thunb.) Matsum. and Nak.] fruit yield and quality by optimizing the choice and use of pollenizers. Treatments were pollenizer cultivars planted singly [‘Companion’, ‘Super Pollenizer 1’ (‘SP1’), ‘Summer Flavor 800’ (‘SF800’), and ‘Mickylee’] or in pairs (‘Companion’ + ‘SP1’, ‘Companion’ + ‘SF800’, and ‘SP1’ + ‘SF800’). All pollenizers from these seven treatments were interplanted with the triploid cultivar Tri-X-313. Planting arrangement was compared by establishing ‘SF800’ in a hill versus an interplanted field arrangement. Effect of pollenizer establishment timing on triploid fruit yields and quality was evaluated by establishing ‘SP1’ 3 weeks after planting and comparing it with the establishment of ‘SP1’ at the time of triploid plant establishment. Finally, a triploid planting with no pollenizer (control) was included to determine pollen movement. Fruit yield from the control was 22% or less of yield of the other treatments containing a pollenizer and less than 10% in the initial or early harvests. Pollen movement was minimal among plots and differences in yield and fruit quality could be attributed to pollenizer treatment. In 2005, the use of ‘Companion’, ‘SP1’, or ‘Mickylee’ as pollenizers produced similar total yields, whereas ‘SF800’ produced the lowest yield. In 2005, ‘Companion’ produced more large fruit than the other individual pollenizer treatments. Combining the pollenizers generally did not enhance triploid yields or quality. Interplanting of pollenizers consistently resulted in greater yield compared with the hill system. Late planting of ‘SP1’ increased the incidence of hollow heart in the marketable fruit and decreased yield compared with simultaneously planting ‘SP1’ and triploid plants. Thus, selection of pollenizer, planting arrangement, and time of pollenizer establishment are all important considerations to optimizing triploid yield and quality.

Maximum Potential Vegetative and Floral Production and Fruit Characteristics of Watermelon Pollenizers

Triploid (seedless) watermelon [Citrullus lanatus (Thunb.) Matsum. and Nak.] pollen is nonviable; thus, diploid (pollenizer) watermelon cultigens are required to supply viable pollen for triploid watermelon fruit set. The objective of this research was to characterize maximum potential vegetative growth, staminate and pistillate flower production over time, and measure exterior and interior fruit characteristics of pollenizer cultigens. Sixteen commercially available and numbered line (hereafter collectively referred to as cultigens) pollenizer and two triploid cultigens were evaluated in 2005 and 2006 at Clayton, NC. Vegetative growth was measured using vine and internode length, and staminate and pistillate flower development was counted weekly. Fruit quality and quantity were determined by measuring individual fruit weights, soluble solids, and rind thickness. Based on vegetative growth, pollenizer cultigens were placed into two distinct groups. Pollenizers, which produced a compact or dwarf plant were ‘Companion’, ‘Sidekick’, ‘TP91’, ‘TPS92’, and ‘WC5108-1216’. Pollenizers having a standard vine length were ‘Jenny’, ‘High Set 11’, ‘Mickylee’, ‘Minipol’, ‘Pinnacle’, ‘Summer Flavor 800’ (‘SF800’), ‘Super Pollenizer 1’ (‘SP1’), and ‘WH6818’. Cultigens with compact growth habit had shorter internodes and vine lengths compared with the cultigens with standard growth habit. Cultigens with the greatest quantity of staminate flower production through the entire season were ‘Sidekick’ and ‘SP1’. The lowest number of staminate flowers was produced by ‘TP91’ and ‘TPS92’. Based on fruit quality characteristics and production, pollenizers currently or possibly marketed for consumption include ‘Mickylee’, ‘SF800’, ‘Minipol’, ‘Jenny’, and ‘Pinnacle’. The remaining cultigens evaluated in this study should be used strictly as pollenizers based on fruit quality. Arrangement of diploid pollenizers in a commercial planting of triploid watermelons is an important consideration depending on plant vegetative development. Based on staminate flower production, cultigens with higher staminate flower production are potentially superior pollenizers and may lead to improved triploid quality and production. Furthermore, pollenizer selection by fruit characteristics should include a rind pattern easily distinguished from triploid fruit in the field.

Evaluación agronómica de tomate (Lycopersicon esculentum M.) en invernadero.

The main objective of this work was to determine the adaptation potential of tomato genotypes for greenhouse. Genotypes evaluated were: hybrids: Contessa, Summer Flavor 5000, Summer Flavor 6000, Celebrity, Bonita, Shady Lady, Sunbolt, Sunny, Heat Wave and Olympic; and the variety Flora Dade, as a check. The variables evaluated were: yield, agroclimatic and physiological. agroclimatic and physiological variables were determine in three evaluations in the crop cycle, at three times/day and two leaf positions, in each evaluation. Significant correlations were found (p≤0.05) between yield in t/ha and mean yield by plant, fruits by plant at harvest, and yield by plant, and between photosynthesis and water use efficiency. Principal component analysis showed first five components have an Eigenvalue greater than one, explaining the first three with a 72% of total variance. The first component, with a 36% of total variance is due to “The yield characteristics” component two, with a 23% of total variance, is due to “internal temperature regulation characteristics” and component five, with a 7.4% of variation, to “photosyntates efficient production”. Multiple linear regression analysis difference was significant (p<0.01). Yield in t/ha was explained by the multiple linear equation (r2 =0.98) of four variables.

Genotypic Variability in Staminate Flower and Pollen Grain Production of Diploid Watermelons

In 1999 and 2000, a total of 27 diploid watermelon [Citrullus lanatus (Thunb.) Matsum. & Nakai] cultivars and advanced breeding lines (hereafter referred to as cultigens) were evaluated for staminate flower and pollen grain production to assess their potential to serve as pollenizers (pollen source plants) in triploid watermelon production systems. Male reproductive output (staminate flower and pollen production) was quantified during the peak flowering and fruit setting phase of the cultigens under field conditions. The number of staminate flowers produced per plant per day, number of pollen grains produced per flower, and total number of pollen grains produced per plant per day (staminate flowers per plant × pollen grains produced per flower) differed greatly among cultigens (for all tests, P < 0.01). Staminate flower production by cultigens differed by year (P < 0.0029) and days within years (P = 0.0225), but pollen production between years by cultigens was stable (P = 0.4841). Total male reproductive output ranged from 134,206 pollen grains per plant per day for `Jamboree' to 321,905 pollen grains per plant per day for `Summer Flavor 500'. These studies demonstrate the genotypic variability in watermelon male reproductive output potential, and may assist growers in choosing a good diploid pollenizer for triploid watermelon production.

COMPARISON OF COMMERCIAL POLLINIZERS FOR TRIPLOID WATERMELON PRODUCTION, 2003

Market demand for diploid fruit has been declining over the past ten years, especially the past three years. Thus, the watermelon industry is looking for ways to produce triploid fruit more efficiently. Several companies have developed pollinizers for planting in-row so as not to take up space like a commercial diploid cultivar. The objective of our experiment was to determine the effects of `Companion' and `SP-1' pollinizers on triploid yield compared with a traditional diploid pollinizer which until recently were routinely sold to grocery chain stores. The experimental locations were Bradenton, Florida and Kinston, NC. Treatments included two triploid cultivars; Tri-X-313 (Syngenta, Rogers Brand Seeds) and Olympia (Seminis Seed Co.), and three pollinizers; `Companion' (Seminis Seed Co.), `SP-1' (Syngenta, Rogers Brand Seeds), and `Summer Flavor 800' (Abbott & Cobb Seed Co.). A seventh treatment included `Tri × 313' in which no pollinizer was planted next to the triploid cultivar. `Companion' was interplanted every two triploid plants. `SP-1' was interplanted every three triploid plants, and `Summer Flavor 800' planted every third hill. All fruit were harvested when ripe and each watermelon was weighed. Results in the Florida location were compromised due to the close proximity of pollen from adjacent watermelon cultivar trials. In North Carolina, some pollen movement did occur between treatment plots as evidenced by fruit set in the `Tri-X-313' plots which did not contain a pollinizer. Yields; however, were 25% to 33% of those treatments which contained a pollinizer. `Tri × 313' yielded greater fruit numbers but individual fruit weights were less than those harvested from `Olympia'. Early fruit yield was similar regardless of pollinizer, while late yields were greater using `SP-1' rather than `Companion' or `Summer Flavor 800'. Cumulative yields (three total harvests) were highest with `SP-1' than the other pollinizers. The use of `SP-1' provided the greatest potential for improved yields over traditional diploid pollinizers.

SOR1, a gene associated with bioherbicide production in sorghum root hairs.

Sorghum [Sorghum bicolor (L.) Moench] roots exude a potent bioherbicide known as sorgoleone, which is produced in living root hairs and is phytotoxic to broadleaf and grass weeds at concentrations as low as 10 microM. Differential gene expression was studied in sorghum (S. bicolorxS. sudanense) cv. SX17 between roots with abundant root hairs and those without root hairs using a modified differential display approach. A differentially expressed gene, named SOR1, was cloned by using Rapid Amplification of the 5' ends of cDNA (5'-RACE). Real-time PCR analysis of multiple tissues of sorghum SX17 revealed that the SOR1 transcript level in root hairs was more than 1000 times higher than that of other tissues evaluated, including immature leaf, mature leaf, mature stem, panicle, and roots with hairs removed. Semi-quantitative RT-PCR revealed that SOR1 was expressed in the sorgoleone-producing roots of sorghum SX17, shattercane [S. bicolor (L.) Moench], and johnsongrass [S. halepense (L.) Pers.], but not in the shoots of sorghum or in the roots of sweet corn (Zea mays L.) 'Summer Flavor 64Y', in which sorgoleone production was not detected by HPLC analysis. Similarity searches indicated that SOR1 probably encodes a novel desaturase, which might be involved in the formation of a unique and specific double bonding pattern within the long hydrocarbon tail of sorgoleone.

Carbohydrate Distribution in a Sweet Maize with the Sugar Enhanced Endosperm Genotype

Knowing how sugar content changes in the whole plant could be useful for predicting sugar content in sweet maize (Zea mays L.) kernels at fresh-market maturity. Levels of fructose, glucose, sucrose, and their total were determined in various tissues over time in the sweet maize cv. Summer Flavor #72Y (su1se1 endosperm). From the 12-leaf to fresh-market maturity stages, Internode 9 that is generally formed below the first ear, was sampled. Entire developing ears were sampled when tassels were extended but unfolded, and at silking. Kernel and cob tissues were sampled separately at blister and fresh-market maturity stages. Patterns of correlations indicated that levels of sugars in vegetative tissues at various developmental stages are interdependent with levels of sugars in kernels. Factors affecting development of plants prior to anthesis may affect sugar levels in kernels at fresh-market maturity.

Genotypic Variability in Staminate Flower and Pollen Grain Production of Diploid Watermelons [Citrullus lanatus (Thunb.) Matsum. & Nakai

In 1999 and 2000, a total of 28 diploid watermelon cultigens (released cultivars and advanced breeding lines) were evaluated for staminate flower and pollen grain production to assess their potential to serve as pollenizers (pollen source plants) in triploid watermelon production systems. Male reproductive output (staminate flower and pollen production) was quantified during the peak flowering and fruit setting phase of the cultigens under field conditions. The number of staminate flowers produced per plant per day, number of pollen grains produced per flower, and total number of pollen grains produced per plant per day (staminate flowers per plant x pollen grains produced per flower) differed greatly between cultigens (for all tests, P < 0.01). Staminate flower production by cultigens differed by year (P < 0.0003) and days-within-years (P = 0.0094), but pollen production between years by cultigens was stable (P = 0.3845). Total male reproductive output ranged from 134,206 pollen grains per plant per day for `Jamboree' to 321,905 pollen grains per plant per day for `Summer Flavor 500'. These studies demonstrate the genotypic variability in watermelon male reproductive output potential, and may assist growers in selecting an optimal diploid pollenizer for triploid watermelon production.

Carotenoids and Quality of Watermelon as Affected by Deficit Irrigation and Growing Season

This experiment was conducted to determine the effects of deficit irrigation and growing season on fruit quality, carotenoid content and yield of red-, orange-, and yellow-fleshed diploid and triploid watermelon. Irrigation rates were 1.0 evapotranspiration (ET) and 0.5 ET. Diploid cultivars were Summer Flavor 710 (red), Tendersweet (orange), and Summer Gold (yellow). Triploid cultivars were Summer Sweet 5244 (red), Sunshine (orange), and Amarillo (yellow). Four-week old containerized transplants were planted in the field at TAES-Uvalde on 27 Mar. and 21 May 2003. Deficit irrigation imposed after plants were fully established reduced the individual fruit weight and size in the early planting. Soluble solids content (SSC) and firmness was not affected by irrigation rate in both plantings. SSC varied across cultivars and increased with maturity, particularly for the triploid cultivar Amarillo. In general, triploids were firmer than diploid cultivars. Total carotenoid content was not affected by irrigation during early planting. Diploid and triploid red-fleshed watermelon cultivars had significantly higher carotenoid content than orange- and yellow-fleshed cultivars. The major carotenoid was lycopene (more than 65%), followed by prolycopene (20%) and B-carotene (7%).

Carbohydrate Distribution in Stalks and Ears of Sweet Maize with Different Endosperm Genotypes

Knowledge about the distribution of sugars in vegetative tissues can provide information about levels of carbohydrates in kernels of sweet maize (Zea mays L.). Levels of fructose, glucose, sucrose and their total were determined over time in stalks and ears in the sweet maize cvs. Summer Flavor #72Y, Merit, and Supersweet Jubilee, which have respectively, the su1se1, su1, or sh2 endosperm types. Internode 9 (19), which is generally formed below the first ear, was sampled from the 12-leaf stage to fresh-market maturity (R3). Entire developing ears were sampled when tassels were extended but unfolded (VN) and at silking (R1). Kernel and cob tissues were sampled separately at blister (R2) and R3 stages. Levels of individual sugars, their total, and levels of starch, water soluble polysaccharides (WSP), and total extractable carbohydrates (added values for individual sugars, WSP, and starch) were determined in kernels at R2 and R3. In 19, levels of fructose and glucose decreased, and sucrose increased in all cultivars after Rl. In developing ears levels of fructose, glucose and total sugar increased from VN to Rl in all cultivars. In cobs, total sugars decreased at R3. In kernels, the sh2 endosperm type cultivar had the highest sugar contents. There was more sucrose in kernels at R3 and more total sugar at R2. The sh2 endosperm type cultivar had the lowest WSP and the highest total carbohydrate levels in kernels at R3. Large changes in sugar content occurs in stalks after R1 and factors interrupting sugar metabolism at this stage, or earlier, may affect levels of sugars in kernels.

Deficit irrigation impact on lycopene, soluble solids, firmness and yield of diploid and triploid watermelon in three distinct environments

SummaryWater conservation practices are critical for production and quality of watermelon [Citrullus lanatus (Thunb.) Matsum & Nakai] in southern regions of the USA. The objective of this experiment was to determine the effects of deficit irrigation and environment on lycopene content, total soluble solids, firmness, and yield of diploid and triploid watermelon. Irrigation rates were 1.0 evapotranspiration (ET), 0.75 ET, and 0.5 ET, which were calculated based on climatic parameters applied to the Penman-Monteith equation. Diploid cultivars were ‘Summer Flavor 710’ and ‘Summer Flavor 800’, and triploid cultivars were ‘Summer Sweet 5244’ and ‘Super Seedless 7187’. To investigate if there was a consistent response in cultivars across diverse environments, three studies were conducted in remote Texas locations: Uvalde in the Wintergarden, Weslaco in the Rio Grande Valley, and Lubbock in the High Plains. To isolate the environmental effects due to weather and soil type, all experiments used similar cultural strategies (plant spacing, subsurface drip irrigation, black plastic mulch, and containerized transplants), except for transplanting and harvesting dates. Deficit irrigation reduced total marketable yield by 36% at Uvalde, 30% at Lubbock, and 15% in Weslaco, increasing the yield of small fruits (<5 kg). Location and irrigation rates had major influences on yield of diploid and triploid watermelon. Soluble solids content increased with deficit irrigation at 0.5 ET rate in triploids, but not in diploids. Flesh firmness also increased in triploids compared to diploids. Fruit lycopene content increased with maturity (7 and 22 d after ripening) at all irrigation rates and cultivars. This work across three diverse Texas locations confirms that deficit irrigation directly reduced yield, but does not reduce lycopene development and fruit quality of triploid watermelon.

Lycopene, carbohydrates, ascorbic acid and yield components of diploid and triploid watermelon cultivars are affected by de®cit irrigation

SummaryMany vegetable production regions in the southwestern US are strictly regulated on water use. In addition, demand for high quality and nutritious vegetables has increased. This study was performed to explore the effects of de®cit irrigation on yield, fruit quality, lycopene content, vitamin C and sugar composition of red-¯eshed diploid and triploid watermelon (Citrullus lanatus (Thunb) Matsum & Nakai) cultivars. Irrigation treatments were 1.0, 0.75 and 0.5 evapotranspiration (ET) rates. Cultivars used were `Summer Flavor 710', `RWM 8036', `Allsweet', `Sugarlee', and `SWD 7302' (diploids) and `Summer Sweet 5244', `SWT 8706', `Sugar Time', and `Tri X Sunrise' (triploids). Total water applied through a subsurface drip system was 395, 298 and 173.mm, for the 1.0, 0.75 and 0.50 ET rates, respectively. Total yields were highest at 1.0 ET (53.9 t ha±1) compared with 0.5 ET (26.8.tha±1). Triploids had a 34% higher total yield and fewer culls (2%) compared with diploid cultivars (25%). Highest yields were obtained for `Tri X Sunrise', `SWT 8706', and `SWD 7302'. `Sugar Time' had the highest soluble solids content (13.4%) of all cultivars (range 9.7±11.0%). Triploid cultivars had ®rmer ¯esh compared to diploids (12.0 v 9.9..N). Lycopene content increased slightly with maturity (55.8 to 60.2.mgg±1 fw), and was signi®cantly higher at 0.75 ET and 1.0 ET. Lycopene content averaged over all treatments was 60±66.mgg±1 fw for triploids and 45 to 80.mgg±1 fw for diploid fruits. Overall, lycopene and vitamin C content did not decrease with de®cit irrigation at 0.75 ET. There was genetic variability for lycopene, vitamin C, and sugar composition, primarily fructose, among diploids and triploids.

Flesh quality and lycopene stability of fresh-cut watermelon

Abstract Red fleshed watermelons are an excellent source of the phytochemical lycopene. However, little is known about the stability of lycopene in cut watermelon. In this study, lycopene stability and other quality factors were evaluated in fresh-cut watermelon. Twenty melons each of a seeded (Summer Flavor 800) and a seedless (Sugar Shack) variety were cut into 5 cm cubes and placed in unvented polystyrene containers, sealed, and stored at 2 °C for 2, 7, or 10 days. At each storage interval, melons were evaluated for juice leakage, changes in carotenoid composition, color, soluble solids content (SSC), and titratable acidity. Headspace carbon dioxide and ethylene were monitored during storage intervals. Juice leakage after 10 days of storage averaged 13 and 11% for the seeded and seedless melons, respectively. Lycopene content decreased 6 and 11% after 7 days of storage for Summer Flavor 800 and Sugar Shack melons, respectively. β-Carotene and cis lycopene contents were 2 and 6 mg kg−1 for Summer Flavor 800 and Sugar Shack, respectively, and did not change with storage. After 10 days of storage, CIE L∗ values increased while chroma values decreased, indicating a lightening in color and loss of color saturation in melon pieces. Symptoms of chilling injury, such as greatly increased juice leakage, or lesions on cubes, were not seen on the fresh-cut cut watermelon after 10 days storage at 2 °C. Puree pH increased and SSC decreased slightly after storage. Carbon dioxide levels increased and oxygen levels decreased linearly during storage, creating a modified atmosphere of 10 kPa each of CO2 and O2 after 10 days. Fresh-cut cut watermelon held for 7 or more days at 2 °C had a slight loss of SSC, color saturation, and lycopene, most likely caused by senescence.

454 Deficit Irrigation Affects Yield and Quality of Triploid and Diploid Watermelon

Water conservation strategies are being investigated for watermelon [Citrullus lanatus (Thunb.) Matsum. &amp; Nakai] production in the Winter Garden region of southwest Texas. Our objective was to determine how yield and fruit quality of a triploid (cv. Summer Sweet 5244) and hybrid (cv. Summer Flavor 710) watermelon were affected by irrigation based on evapotranspiration (ET) rates and timing of application during spring. Irrigation treatments included constant 1.0 and 0.5 ET, three with varying ET before or after fruit set, and one with cycles of 1.0 and 0.5 ET. Fruit quality characteristics were measured at the unripe, ripe, and overripe maturity stages. Water deficit before or after fruit set decreased yield and fruit number. Flesh color was not affected by irrigation at any maturity stage. Soluble solid content at the ripe stage increased only in triploids irrigated with constant 0.5 ET or with 0.5 ET applied after fruit set. Triploid plants exposed to frequent cycles of water deficit set more and smaller fruit than hybrids. These data suggest that triploid watermelon types may have a different acclimation response to drought stress than diploid hybrids.

INFLUENCE OF POULTRY LITTER ON TOMATO YIELD, NUTRITION, AND SOIL CHEMISTRY

Composted poultry litter (PL) containing 2.98% N was hand-applied on individual plots in a RCB design with 3 replications. Rates (0, 8.2, and 16.3 Mg·ha-1) were based on N content of the PL and requirement for maximum tomato production. Comparisons were made with a fertilizer blend (FB) containing 558 kg·ha-1 of 14.1N-5.7P-9.2K applied in split application. `Summer Flavor 5000' tomato plants were hand-planted 46 cm apart in rows spaced 3 m apart. Plant volume and average fruit weight were not influenced by any treatment. A 5920 kg·ha-1 yield increase was noted when PL rate was increased from 0 to 8.2 Mg·ha-1. Total yield was further increased 2757 kg·ha-1 by doubling the PL rate. Yields due to FB were lower but not significantly when compared to PL rates. This decrease in yield could possibly be attributed to FB lowering soil pH to borderline levels for production (5.7) while litter rates had little effect on pH. No differences in leaf P and K were measured. Both rates of PL decreased leaf Ca but increased Mg as rate increased. There was no difference in leaf N, P, K, Ca, or Mg when zero PL and FB were compared. FB increased soil NO3-N in the 0- to 30-cm depth zone more than the PL treatments. When comparing the highest PL rate to the lowest, there was almost a one and one-half time increase in residual soil K at the 0- to 15-cm soil depth. PL increased soluble salts only in the 0- to 15-cm soil depth, however, levels were low.

Uniconazole controls growth and yield of greenhouse tomato

Tomato ( Lycopersicon esculentum cultivar ‘Summer Flavor’) seedlings received a single uniconazole soil drench at 0, 12.5, 25, 50, 100, 200 or 400 μg per plant at the five-leaf stage. After 2 weeks of growth, plant height, length and area of the fifth leaf, and plant fresh and dry weights progressively decreased with increasing rates of uniconazole. The rate of leaf production was unaffected at low rates of the retardant. Another group of seedlings received soil drenches at the above rates at the onset of flowering. Uniconazole applied at both stages resulted in short final plant height at all rates. Total fruit yield was reduced by uniconazole at the 12.5 μg per plant rate, with further reduction as rates increased. Yields of large fruits (≥ 110 g) increased at the two lower rates of uniconazole. The incidence of blossom-end rot (BER) was nearly eliminated by this retardant at all rates. Foliar application of uniconazole at the flowering stage with rates of 0, 25, 50, 100, 250, 500, 750 or 1000 μg per plant had less control on plant height compared with their respective rates as a soil drench. Total fruit yield was not affected until the rate exceeded 100 μg per plant. The incidence of BER decreased sharply with increasing rates of uniconazole. The number and weight of fruits ≥ 110 g were doubled at rates between 25 and 250 μg per plant. Plant fresh and dry weights were lower as a result of uniconazole foliar spray. Fruit number was reduced regardless of the rate and stage of uniconazole application.