MSU Extension Vegetables

Objective

The objective of this trial was to evaluate yield and quality of 19 fresh market and six saladette tomato varieties grown in a plasticulture system in Southwest Michigan.

Summary

The best overall performing fresh market tomato entries as measured by high total and number one yield, low number two and cull yield and high fruit weight were Volante, Mountain Majesty and Red Morning. The best overall performing red saladette entry as measured by high total and number one yield and low number two and cull yield and a relatively large average fruit size was Plum Regal. For growers with a market for orange fruit, Orange Roma had decent yield performance but was relatively small in fruit size.

Methods

Planting

On 17 April, 2015, seed of the 25 cultivars was planted into 72 cell transplant trays and placed into a commercial greenhouse. Transplants were set to the field into a plasticulture system 28 May as separate saladette or fresh market trials. Beds were six-inches high with a spacing of 5.5 feet between beds and 18 inches between plants in the row (5,280 plants/acre). A drip irrigation line was inserted in the bed at the time of bed shaping and plastic mulch application. Plants were pruned and trained to a stake and weave system. Trials were planted and analyzed as a completely randomized design with four replications and eight plants/plot. 

Fertilizer

Prior to bed shaping, 44-0-0, 0-0-64, sulfur and Granubor were broadcast and incorporated at a rate of 75, 330, 27 and 7 pounds per acre, respectively. After planting, liquid 28-0-0 and 0-0-30 were applied through the drip system once a week at a rate of 1 pound nitrogen and 2 pounds potassium/acre/day.  Drip fertilization began the week of 22 June and ended the week of 17 August for a post-plant total of 63 and 126 pounds per acre nitrogen and potassium, respectively. 

Pest Control

Weeds between rows were controlled when they were small with Gramoxone applied using a backpack sprayer. Diseases and insects were controlled using commercially recommended practices. 

Harvest and Data Collection

Plots were harvested six times; 12, 19 and 27 August and 2, 16 and 28 September.  Fruit was graded into number 1, number 2, and culls. Number of number one fruit was counted so average number one fruit weight could be determined. Data from the two trials was analyzed separately. 

Results and Discussion

The 2015 growing season proved to be difficult for tomatoes planted in late May. Cool, wet weather (five inches of rain during June) shortly after planting contributed to early disease development making it especially difficult to control bacterial spot (Xanthomonas campesiris pv, vesicatoria), bacterial speck (Pseudomonas syringae pv. tomato) and bacterial canker (Corynebacterium michiganense pv. michiganense).

Total yield for the fresh market cultivars ranged from 1764 to 2939, 25 pound cartons/acre with eight entries being statistically similar in total yield (Table 1). Volante, Red Morning and Mountain Majesty had similar yield of number one fruit at 1898, 1610 and 1529 cartons/acre, respectively. Seven entries had similarly high average number 1 fruit weights (Table 1). The best overall performers (high total and number one yield, low number two and cull yield and high fruit weight) were Volante, Mountain Majesty and Red Morning (Table 1). While grading fruit it was also noted that Volante and Red Mountain had particularly attractive fruit. Pictures of each entry were taken at the third harvest (Figures 1 to 5).

Total yield for the saladette tomatoes ranged from 1396 to 2244, 25 pound boxes/acre (Table 2).  Orange Roma, Pasiano, Plum Regal and Conan had similarly high total yields. Orange Roma and Plum Regal also had similar yield of number one fruit while Conan had the highest average number 1 fruit weight. Plum Regal and Supremo ranked in the second tier for fruit size. The best overall performing red entry was Plum Regal with high total and number one yield and low number two and cull yield and a relatively large average fruit size. For growers with a market for orange fruit, Orange Roma had decent yield performance but was relatively small in fruit size. Pictures of each entry were taken at the third harvest (Figures 6 and 7). 

High number of cull fruit may not necessarily be indicative of the particular entry but may be a function of weather conditions leading to eventual disease expression. In another year with more favorable weather, performance may improve. The trial seemed to have more cracked and misshapen fruit than what we generally experience and these would have been placed into the cull category.

Table 1. Yield in cartons per acre and average number one fruit size in grams of 19 fresh market tomatoes grown at the Southwest Michigan Research and Extension Center, Benton Harbor, Michigan in 2015. Plant spacing was 5.5 feet between rows and 18-inches in the row for 5,280 plants/acre. Numbers in bold are not different than the best performer.

Table 2. Yield in cartons per acre and average number one fruit size in grams of 6 saladette-type tomatoes grown at the Southwest Michigan Research and Extension Center, Benton Harbor, Michigan in 2015. Plant spacing was 5.5 feet between rows and 18-inches in the row for 5,280 plants/acre. Numbers in bold are not different than the best performer.