Grape Tomatoes Research Articles

Development of a Nitrogen Fertigation Program for Grape Tomato

ABSTRACT Grape tomatoes (Solanum lycopersicon L. var. cerasiform) have recently gained in popularity among consumers because they can be eaten without being cut, they are deep red in color, and their flavor is intense and pleasant. Current nitrogen (N) fertilization recommendations were developed for determinate tomato varieties that have a 3-month long growing season, whereas that of the indeterminate grape cultivars may be up to six months. ‘Tami G’ grape tomatoes were grown on a Lakeland fine sand at the North Florida Research and Education Center—Suwannee Valley, near Live Oak, FL in Springs 2005 and 2006 using standard plasticulture practices under 0%, 33%, 66%, 100%, 133%, and 166% of the current recommended N rate for round tomato (224 kg/ha). Due to a longer growing season in 2006, plants received an additional three weekly injections of 22 kg/ha of N each in the 100% rate, that were also proportionally applied to the other treatments. Tomatoes were transplanted March 24, 2005 and April 4, 2006 and harvested, weighed and graded five (2005) and seven (2006) times. Season marketable yield (SMY) responses to N rates were quadratic (both years P < 0.01) and highest SMY (40,340 and 36,873 kg/ha) occurred with 314 and 280 kg/ha of N in 2005 and 2006, respectively. Fruit soluble solids concentrations ranged from 6.25 to 7.5, and 7.0 to 8.3° Brix in 2005 and 2006, respectively, and were not significantly affected by N rate. These results suggest that N fertilization for grape tomato grown in Spring with plasticulture could be done by incorporating 56 kg/ha of N in the bed, followed by daily rates ranging from 0.5 to 3.5 kg/ha/day. Because the length of the growing season for grape tomato may vary, emphasis should be placed on daily N rates and irrigation management, rather than on seasonal N rate.

Effects of Nitrogen Rates on Chemical Composition of Yellow Grape Tomato Grown in a Subtropical Climate

ABSTRACT Grape tomatoes (Lycopersicon esculentum Mill.) are gaining popularity among consumers because of their flavor, sweetness, potential health benefits, and ease of consumption. Most grape tomatoes are indeterminate varieties. Hence, current production practices (including fertilization rates) may need to be adjusted to larger plants, longer growing seasons, and harvests over several months of the indeterminate varieties. The responses of physical (color and moisture content) and chemical [vitamin C, pH, total titratable acidity (TTA), carotenoids, and soluble solid content (SSC)] parameters for ‘Honey Bunch’ yellow grape tomato to nitrogen (N) rates were evaluated. In Spring 2005, tomatoes were grown on a Lakeland fine sand in North Florida using plasticulture and N rates of 0, 78, 157, 235, 314, and 392 kg/ha. Tomatoes were harvested fully ripen on 81 and 105 d after transplanting (DAT = 0 on March 24th), and uniform 20-fruit samples were carefully selected. Increasing N rate significantly reduced vitamin C concentration from 44 to 35 mg/100 g and TTA from 0.47% to 0.38% citric acid, but did not significantly affect lutein (mean = 0.26 micro-g/g) and β-carotene (mean = 0.82 micro-g/g) concentrations or color. Response of pulp pH to N rate was significant but within the narrow 4.5 to 4.7 range. Soluble solid contents decreased as N rate decreased for the first harvest (8.1 to 5.6 for 0 to 392 kg/ha of N), but increased for the second harvest (6.9 to 10.1 for 0 to 314 kg/ha of N). Overall, N rate did not have a marked effect on selected quality parameters, suggesting that variety and/or other environmental factors may be more important than N rate in determining chemical composition of grape tomato.

TAMI G GRAPE TOMATO RESPONSE TO NITROGEN RATES

Grape tomatoes (Lycopersicon esculentum Mill.) have recently gained in popularity among consumers because they can be eaten without being cut, they are deep red in color, and their flavor is intense and pleasant. Current N fertilization recommendations have been developed for determinate tomato varieties that have a 3-month long growing season, whereas that of the indeterminate grape cultivars may be up to six months. 'Tami G' grape tomatoes (previously identified as a suitable alternative to 'Santa') were grown on a Lakeland fine sand at the North Florida Research and Education Center-Suwannee Valley, near Live Oak, FL in the Spring of 2005 using standard plasticulture practices under 0%, 33%, 66%, 100%, 133%, and 166% of the current recommended rate for round tomato (224 kg/ha). Tomatoes were transplanted 24 Mar. and harvested, weighed and graded five times between 10 June and 15 July. Soluble solid concentrations (SSC) were also measured at each harvest. Season marketable (SMY, kg/ha) and total yield (TY, kg/ha) response to N rates were quadratic (SMY = -0.16 Nrate 2 + 140 Nrate + 11,821 R 2 =0.56; CV=32%; TY = -0.18 Nrate2 + 153 Nrate + 13949; R 2 =0.54, CV=32%; both p<0.01). Highest SMY and TY occurred between 314 and 392 kg/ha N rates. N rate effect on SMY and TY was significant only for harvest 4 and 5. SSC ranged from 6.25 to 7.5°Brix for harvests 1 to 4 and was not significantly affected by N rate. On harvest 5, SSC tended to be greater with higher N rates. These preliminary results suggest that N fertilization for grape tomato could be done by incorporating 56 to 78 kg/ha of N in the bed, followed by daily rates ranging from 0.5 to 3.5 kg/ha/day. Because the length of the growing season for grape tomato may vary, emphasis should be placed on daily N rates and irrigation management, rather than on seasonal N rate.

Postharvest Quality of Grape Tomatoes Treated with 1-Methylcyclopropene at Advanced Ripeness Stages

Grape tomatoes (Lycopersicon esculentum Mill. `Santa') harvested at light-red (&gt;90% color) and full-red stages were treated with 1 μL·L–1 1-methylcyclopropene (1-MCP) for 24 hours at 20 °C and stored at 20 °C. After 1 day of storage, fruit harvested at light-red stage treated with 1-MCP had a 56% lower respiration rate than untreated fruit. By day 7, respiration rates of the two treatments had converged at about 2 mL·kg–1·h–1. Ethylene production of light-red stage tomatoes treated with 1-MPC was 24% lower than untreated during storage, with rates converging by day 11. For fruit harvested full-red, 1-MCP had similar effects on respiration and ethylene production, although convergence occurred earlier, by day 5. Subsequent tests were conducted only with fruit harvested at full-red stage, since fruit harvested at the light-red stage had lower soluble solids content (4.3%) than fruit harvested at the full-red stage (5.5%). Several combinations of 1-MCP concentrations and exposure times were applied at 20 °C: 1 μL·L–1 for 24 h, 5 μL·L–1 for 6 or 12 h, 25 μL·L–1 for 6 or 12 h, and 50 μL·L–1 for 6 or 12 h; following the respective pretreatment fruits were stored at 20 °C. 1-MCP pretreatment extended marketable life by 1 d, irrespective of pretreatment regime, where untreated and pretreated fruit remained marketable (&lt;15% of fruit soft, decayed and/or shriveled) for 6 and 7 d, respectively. However, 1-MCP did not affect whole fruit firmness, epidermal color, internal color, soluble solids content (6.5%), total titratable acidity (0.64%), or pH (4.3). In a third test simulating commercial handling procedures, full-red harvested tomatoes were treated with 1 μL·L–1 1-MCP for 24 h at either 13 or 20 °C, stored for 4 d at 13 °C, and then transferred to 20 °C. Under these conditions, marketable life for untreated and 1-MCP-treated tomatoes was 7 and 8 d, respectively.

Alternaria malorum: a mini-review with new records for hosts and pathogenicity

Modern host-fungus indices and databases contain deceptively few entries for Alternaria malorum or its synonym, Cladosporium malorum . Close inspection of literature from the 1930s through the 1960s indicates more hosts and wider prevalence than more modern indices and databases indicate. Reports from 2002 to the present document diverse additional hosts in the Pacific Northwest, including this report from roots of Pinus ponderosa and Pseudotsuga menziesii , the first reports from gymnosperms. Cherry tomato and grape tomato ( Lycopersicon esculentum ) were found to be hosts for A. malorum by artificial inoculation. Rarely documented in synoptic indices or databases in the last 20 years, the Cladosporium-like C. malorum is neither rare nor a true Cladosporium.

Macronutrient intake during the pre-onset, acute, and post weight-recovery period in women with anorexia nervosa: The national heart, lung, and blood institute growth and health study

Macronutrient intake during the pre-onset, acute, and post weight-recovery period in women with anorexia nervosa: The national heart, lung, and blood institute growth and health study