LSU AgCenter Spring 2020 & 2021 Bell Pepper Variety Trials

Introduction:

Bell peppers (Capsicum annuum) are grown throughout the world in mild to moderately warm climates. The United States ranks fifth in global production with the majority of production occurring in California, Florida, Georgia, New Jersey, Ohio, North Carolina and Michigan (Food and Drug Administration, 2020). Bell peppers are highly desired by customers. Especially in Louisiana, where bell peppers are a main ingredient in Cajun and Creole cuisine. They are noted as being highly nutrient dense. Bell peppers are low in calories and fat and contain some protein and fiber. They are also rich in antioxidants, Vitamin A, Vitamin B6 and Vitamin C. One study found consumption of bell peppers may lower cancer risks (Aghajanpour, M. et al., 2017).

In Louisiana, 191 acres of bell peppers were planted with an estimated gross farm value (GFV) of $2.58 million (Louisiana State University Agriculture Center, 2018). This crop is also valued among Louisiana home gardeners. Two bell pepper diseases, bacterial spot (Xanthomonas campestris pv. Vesicatoria) and bacterial speck (Pseudomonas syringae pv. Tomato and Pseudomonas syringae pv. Syringae) were particularly common in Louisiana home gardens in the springs of 2018 and 2019 (personal correspondence with several county agents: commercial producers and home gardeners). The two diseases are visually hard to distinguish. They have greasy water-soaked spots on foliage and sometimes on stems. Small pinpoints may also appear on the fruit (Ivey and Miller, 2020). When infections are extreme, the leaves will fall off the plant simply by touching it. Seeds may be sanitized with a bleach and hot water treatment. The hot water and bleach treatment is as follows: “dip seed in a solution containing 1 quart of household bleach and 4 quarts of water plus one-half teaspoon of surfactant for 1 minute. Provide constant agitation. Use 1 gallon of solution per pound of seed. Prepare a fresh solution for each batch of seed. Wash seed in running water for 5 minutes and dry seed thoroughly. The final rinse should be done with acidified water (1 oz. vinegar per gallon of water). For details on the hot water and bleach treatment, refer to page 101 in the SE Vegetable Crop handbook located at this web link: 2020 Southeastern Vegetable Extension Workers. Once planted, small plants are typically sprayed with copper fungicide treatments early in the season. These are techniques often used by commercial producers but not widely adapted by home gardeners. Louisiana citizens know that Louisiana’s climate is hot and humid. This type of weather magnifies pathogen spread. According to the weather channel, average statewide temperatures range between 54°F and 91°F March through July, with extreme highs in the low 100’s. Average rainfall varies, from a little over 4 inches of rain throughout March, April, and May. Whereas, an average of 8 inches of precipitation occurs in June and an additional average of 6 inches occur in July. This climate lends itself to being disease prone. Additional but not all, pepper disease that Louisiana commercial producers and home gardeners face are Tomato Spotted Wilt Virus (TSWV), Southern blight and Bacterial wilt. Therefore, six varieties of bell peppers labeled as resistant to bacterial spot and other diseases were evaluated in southern and northern Louisiana, to determine if they would produce well for both commercial and hobby production. Note: we did not inoculate pepper plants so we cannot determine from this study the level of resistance.

Materials and Methods:

Seed from six varieties of bell pepper were obtained from Bayer U.S. Crop Science including Autry, Green Machine, 7768, 9325, Playmaker and Turnpike. ‘Autry’ and ‘Green Machine.’ These varieties are labeled as having resistance to Tomato Spotted Wilt Virus (TSWV) and bacterial leaf spot. Seminis uses the label X10R meaning the hybrid has a comprehensive resistance to bacterial spot races 01-10. The seed was planted in a peat-based potting medium (SunGro Metro-Mix 830, Sun Gro Horticulture, Agawam, MA) in 50 count cell trays (T.O. Plastics Clearwater, MN) on February 14, 2020, and March 4, 2021. Trays were placed on heat mats set at 80°F for 48 hrs and then placed into a greenhouse. Trays were watered daily by hand and fertilized after the first true leaf emerged using a liquid fertilizer (Peter’s Professional 20-20-20 fertilizer; ICL Specialty Fertilizers, Summerville SC) at 200 ppm N weekly. Plants were hardened in a shade house covered with 50% shade cloth for one week prior to transplanting. A northern and southern Louisiana location were selected for field evaluation. The southern location was in Baton Rouge Louisiana at the Louisiana State University Agriculture Center’s (LSU AgCenter) Botanic Gardens (30° 24' 32.1012'' N by 91° 6' 21.0132'' W). The northern location was in Homer, Louisiana at the Hill Farm Research Station (32° 45' 10.872'' N93° 3' 42.012'' W). At each location, the peppers were planted into 4 ft wide by 10 ft long plots and double drilled at 12 in spacing between plants. Each variety was replicated in three plots with 20 plants per plot. The southern location peppers were planted on March 31, 2020, and April 22, 2021, on black plastic with drip irrigation. The Northern location peppers were planted on April 17, 2020, and April 230, 2021. Plastic mulch was not used at the northern location. Bell peppers were irrigated using drip irrigation. Preplant fertilizer using 13-13-13 (Magic Carpet, Greenpoint Ag, DeCater, AL) at a rate of 700lbs per acre was applied before planting. Once flowering began, the peppers were side dressed weekly with calcium nitrate using guidelines in the 2019 Southeastern Vegetable Crop Handbook (Kemble et al., 2019). Plots were harvest six times at each location. Data was collected on marketable and unmarketable weight and number of peppers harvested per plot. Ten pepper fruit selected at random from each plot at each harvest date were also measured for average height and two perpendicular widths to better understand average individual pepper size. Note: The goal was to measure 10 fruit per plot in each variety. On some harvest dates we had enough fruit from all varieties and others we did not have 10 fruit per plot (a total of 30 fruit measured per variety on each harvest date) Data were pooled for the north and south locations and are shown in the results section of this report. Please note: the north Louisiana location did not have 60 plants total for each variety. Fifteen plants were planted per plot, totaling 45 plants per variety. Therefore, the total harvest in both locations reflect 105 plants per variety. Some plants were lost to transplant shock and were only replaced after one week.

Results:

2020 Yields

‘Turnpike’ produced more marketable fruit than all other tested varieties. There was little difference in marketable fruit production of ‘SVPB’, “PS09979325’, ‘Playmaker’, ‘Green Machine’ and ‘Autrey.’ Marketable fruit production greatly outweighed that of non-marketable fruit in all varieties. Unmarketable or cull fruit in this trial were any that had a blemish from insect, disease, or environmental damage. Fruit were also culled if they did not meet the USDA No 1 marketable size defined as “the diameter of each pepper shall be not less than 2-1/2 inches and the length of each pepper shall be not less than 2-1/2 inches” (United States Department of Agriculture Marketing Service, 2020).‘Green Machine’ and ‘PS09979325’ had more marketable fruit than the other tested varieties but without a significant difference. Naturally, as ‘Turnpike’ produced the most fruit, it also had the highest marketable fruit weight. As with fruit number all other tested varieties did not significantly differ in marketable fruit weight. Cull fruit weight was greatest in PS09979325 and Green Machine but these varieties did not significantly different in cull weight compared to the remaining tested varieties (Figure 1). Reminder the yields given reflect a total of 105 plants over 6 harvests in a three-week period in two locations. In hindsight, we should have included a bell pepper commonly grown by Louisiana commercial producers. At the south Louisiana location, ‘Aristotle’ a commonly grown commercial bell pepper was planted in an All-American Selection Garden (AAS). When we began harvest of this trial, we also asked if we could harvest the ‘Aristotle’ peppers from the AAS garden. Granted permission, the ‘Aristotle’ peppers were harvested on the same dates as this trial. There were only 40 Aristotle plants in total and in the six harvest periods, those plants produced a total of 133 marketable fruit, 56.3 marketable lbs. of fruit, 54 unmarketable fruit and 18.3 lbs. of culled fruit. The 40 Aristotle plants represent roughly 40% of the initial plants included in this trial. It is a far stretch to compare this variety to our trials since they were in different fields and fertilized and irrigated slightly different. Nevertheless, we wanted to see if there was similarity between the ‘Aristotle’ and any peppers in our trial. If we take 40% of the marketable fruit number of ‘Turnpike’ we see that ‘Turnpike’ slightly outperforms ‘Aristotle’ and ‘Aristotle’ marketable fruit number is very comparable to that of ‘Playmaker’ and ‘Green Machine.'

2021 Yields

Again, Turnpike outperformed all other tested varieties in terms of number of fruits harvested and total marketable weight (lbs.) of peppers.

2020 Size

Data were collected on average pepper fruit width (two perpendicular measurements across the shoulder of the fruit) and the height of each pepper fruit. On average ‘Turnpike’ fruit were similar in length to ‘Aristotle’ the other pepper varieties were shorter than ‘Aristotle’ but not significantly. ‘PS09979325’ were closest to ‘Aristotle’ in terms of width but again this and the other tested varieties were very similar in terms of size. All peppers were large and blocky, four lobed peppers.

2021 Size

There were very little differences in bell pepper size in the 2021 season. Turnpike was the largest pepper with average widths of 2.7inches and lengths of 3.1 inches.

Discussion:

Overall, all pepper varieties performed well. There was some plant loss in the north Louisiana location due to transplant shock. In the south Louisiana location, we did not lose plants but in the first block (or first set of plots (plot #1 for all varieties) many of the plants on the right side of the double drilled peppers were stunted. The irrigation line ran between the two drills. We have no rational explanation for the plant growth difference on the right side of the drills in the first plots. With this first year of data, we were impressed with the yield and fruit size on ‘Turnpike’, ‘Playmaker’ and ‘Green Machine’. The second year confirmed ‘Turnpike’ is a great choice for commercial production in Louisiana. Based on 2020 and 2021’s performances, all varieties would be recommended to Louisiana home gardeners and ‘Turnpike’ to commercial producers. Not recorded, but after official harvest were concluded, we noticed the size of the “SVPB 7768’ and ‘Green Machine’ pepper fruit size remained very large as compared to the other varieties. This is worth noting as often times; in Louisiana, we see a decrease in average fruit size over the course of the entire spring harvest season. Additionally, we noted that none of the peppers in the trial suffered from bacterial spec or spot. However, we also did not inoculate the peppers. But this is a promising sign.

Literature Cited

Aghajanpour, M., M. Reza Nazer, Z. Obeidavi, M. Akbari, P. Ezati, and N. Moradi Kor. 2017. Functional foods and their role in cancer prevention and health promotion: a comprehensive review. Am. J. cancer Res. 7(4):740-769.

Food and Drug Administration. Western Institute for Food safety and Security. Bell and Chile Peppers. 31 August 2020.

Ivey, M., S. Miller. 2020. Bacterial Leaf Spot of Tomato. 31 August 2020.

Ivey, M., S. Miller. 2020. Bacterial Leaf Speck of Tomato. 31 August 2020

Kemble, add other editor. Southeastern Vegetable Crop Handbook. 2019.

Louisiana State University Agriculture Center. 2018. Louisiana Summary Agriculture and Natural Resources. 31 August 2020.

The Weather Channel. Louisiana weather. 5 October 2020.

1/10/2022 8:34:21 PM
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