Evaluating the effects of variety and production system on the development of silvering in bell pepper fruit

Final Report for ONE06-066

Project Type: Partnership
Funds awarded in 2006: $9,824.00
Projected End Date: 12/31/2006
Region: Northeast
State: New Jersey
Project Leader:
Andy Wyenandt
New Jersey Agricultural Experiment Station
Expand All

Project Information

Summary:

The purpose of the study was to examine the effects of production system and cultivar on the development of skin separation or ‘silvering’ in bell pepper fruit. Percentage of bell pepper fruit with ‘silvering’ varied significantly depending on bell pepper cultivar and production system. Percent silvering among cultivars was highest when bell peppers were grown in double rows on raised black plastic mulch with drip irrigation (23%) followed by peppers grown in single rows on raised black plastic mulch with drip irrigation (13%), peppers grown on high bare soil beds with buried drip irrigation (10%) and peppers grown on high, ridged, bare soil with overhead irrigation (7%). Across all 4 production systems at RAREC, percent silvering was highest in phytophthora-tolerant bell peppers cultivars Paladin (23%) and Aristotle (21%) followed by Revolution (9%) and phytophthora-susceptible cultivars, Camelot (7%) and Alliance (6%). At on-farm sites, percent silvering was highest when bell peppers were grown in single rows on raised black plastic mulch beds (16%), followed by peppers grown on high bare soil beds with buried drip irrigation (14%), followed by peppers grown on high ridged bare soil with overhead irrigation (10%). Interestingly, the 3 on-farm site production systems followed the same pattern of silvering development based on production system as the RAREC site.
In general, more silvering developed when peppers were grown in double or single rows on raised black plastic mulch beds with drip irrigation than when peppers were grown on raised bare soil beds with buried or overhead irrigation. More fruit silvering developed on highly tolerant phytophthora cultivars Paladin and Aristotle compared to the intermediate-tolerant cultivar Revolution and phytophthora-susceptible cultivars Alliance and Camelot.

Introduction:

Phytophthora-tolerant bell peppers are one of the most widely grown vegetable crops in New Jersey. In recent years, ‘silvering’ or skin separation has become a serious fruit disorder in bell pepper production in New Jersey and other northeastern states. As pepper fruit mature, the outer epidermis may develop ‘silver’ colored flecks. These flecks are thought to be caused by the separation of the outer epidermis from the rest of the fruit. Although silvering does not affect fruit integrity, it reduces fruit quality making affected fruit less marketable. Depending on commercial cultivar, silvering can be as high as 60% in early-harvests and as high as 30% in late-harvests. Interestingly, the silvering of fruit has been linked to Phytophthora-resistance in commercial bell pepper cultivars. The more resistant the pepper cultivar is to Phytophthora blight, the more likely it is to develop silvering. Because Phytophthora blight is such a serious problem, Phytophthora-resistance/tolerant cultivars are grown on approximately 75% of the commercial acreage in New Jersey. Unfortunately, this makes a large percentage of bell pepper production acreage in the state susceptible to silvering. According to USDA grading standards, #1 bell peppers can have no more than 10% fruit with silvering along with other defects. Because of the high amount of acreage grown to Phytophthora-resistant bell peppers in New Jersey, finding cultivars and production practices which can reduce silvering in fruit is critical for pepper production in New Jersey and the northeast.

Project Objectives:

The purpose of the study was to examine the effects of production system and cultivar on the development of skin separation or ‘silvering’ in bell pepper fruit.

Cooperators

Click linked name(s) to expand
  • Wesley Kline
  • Buddy Laning
  • Robert Martino
  • David Sheppard

Research

Materials and methods:

This experiment, arranged as randomized complete blocks with 4 replications, was conducted at the Rutgers Agricultural Research and Extension Center (RAREC), Bridgeton, New Jersey and at one on-farm site in Vineland and two on-farm sites in Cedarville, New Jersey. Five bell pepper cultivars (Camelot, Alliance, Revolution, Aristotle, Paladin) with no, or varying levels of resistance to the crown rot phase of Phytophthora blight (Phytophthora capsici) were transplanted by hand on 18 May at on-farm site 1 in single rows in black plastic mulch with drip irrigation, on 19 May at on-farm site 3 in high, ridged, bare soil beds with overhead irrigation and on 22 May at on-farm site 2 on high, raised bare soil beds with buried drip irrigation. At each on-farm site, plots were 15 ft long (9 plants/plot) with 5 ft in-row breaks between plots. On 1 June, all three on-farm site production systems were replicated with one additional production system consisting of peppers grown in double rows (18 plants/plot) in raised black plastic mulch beds with drip irrigation (RAREC) in a field (aura sandy loam) located at RAREC. All treatment plots were 15 ft long with 5 ft in-row breaks and guard rows planted on the outside of each plot. On 31 May, the herbicides, Devrinol and Dual Magnum, were pre-plant incorporated at RAREC at a rate of 1lb/A and 1 pt/A, at bed formation, respectively. Fertility schedules were followed according to standard production practices by each cooperating farmer at each on-farm site and replicated at RAREC. The cooperating grower did management of insects and weeds according to local recommendation guidelines at each on-farm site. All mature pepper fruit from 15 ft of each treatment row were harvested on 2 Aug, 15 Aug, 7 Sept, 28 Sept, and 12 Oct at RAREC; and on 24 Jul, 11 Aug, 1 Sept, 20 Sept, and 5 Oct at on-farm site 3; and on 4 Aug, 18 Aug, 8 Sept, 29 Sept, and 11 Oct at on-farm site 2; and on 24 July, 18 Aug, 8 Sept, and 28 Sept at on-farm site 1. All fruit were graded, separated, scored for the presence of skin separation (silvering) and weighed for statistical analysis.

Research results and discussion:

At RAREC, the effects of 4 production systems and 5 cultivars on the development of silvering in bell pepper fruit and percentage of bell pepper fruit with ‘silvering’ varied significantly depending on bell pepper cultivar and production system. Percent silvering among cultivars was highest when bell peppers were grown in double rows on raised black plastic mulch with drip irrigation (23%) followed by peppers grown in single rows on raised black plastic mulch with drip irrigation (13%), peppers grown on high bare soil beds with buried drip irrigation (10%) and peppers grown on high, ridged, bare soil with overhead irrigation (7%). Across all 4 production systems at RAREC, percent silvering was highest in phytophthora-tolerant bell peppers cultivars Paladin (23%) and Aristotle (21%) followed by Revolution (9%) and phytophthora-susceptible cultivars, Camelot (7%) and Alliance (6%). At on-farm sites, percent silvering was highest when bell peppers were grown in single rows on raised black plastic mulch beds (16%), followed by peppers grown on high bare soil beds with buried drip irrigation (14%), followed by peppers grown on high ridged bare soil with overhead irrigation (10%). Interestingly, the 3 on-farm site production systems followed the same pattern of silvering development based on production system as the RAREC site.

Research conclusions:

The results of this one-year trial comparing the effects of production system and cultivar on the development of silvering suggest that production system has an effect on the development of silvering in bell pepper fruit. In general, more silvering developed when peppers were grown in double or single rows on raised black plastic mulch beds with drip irrigation than when peppers were grown on raised bare soil beds with buried or overhead irrigation. More fruit silvering developed on highly tolerant phytophthora cultivars Paladin and Aristotle compared to the intermediate-tolerant cultivar Revolution and phytophthora-susceptible cultivars Alliance and Camelot.

Participation Summary

Education & Outreach Activities and Participation Summary

Participation Summary:

Education/outreach description:

Results of this study have been summarized and presented at the Annual Mid-Atlantic Vegetable Workers Conference held in November in Newark, DE, and at the regional NE-APS meeting in Burlington, VT, and be will presented to bell pepper growers, researchers and extension personnel at state and regional meetings throughout the Northeast in 2007, including the New Jersey Annual Vegetable Growers’ Meeting held in January of each year and at other regional meetings. Research results will be included in the Rutgers Agricultural Research and Extension Center (RAREC) Annual Research Report, presented to the Pepper Advisory Board (consisting of pepper growers and extension personnel) of New Jersey, included in state and regional research reports and newsletters, such as the NJAES Plant and Pest Advisory. In spring of 2007, data will be compiled to be included in a Rutgers Cooperative Extension (RCRE) Fact Sheet which will be available on-line.

Project Outcomes

Project outcomes:

No formal economic analysis was done. First, the exact cause(s) of silvering must be determined so an economic analysis can be carried out. Until that time, economic losses to bell pepper producers due to the disorder could be in the millions of dollars annually if the exact nature of the disorder is not determined.

Farmer Adoption

Changes in production system, such as adopting, raised bare soil beds with drip irrigation instead of raised beds with black plastic mulch, and/or changing cultivar based on the potential for phytophthora development may be simple solutions easily adopted by commercial pepper producers throughout the northeast. Such that, in some areas in the state and region where potential losses due to phytophthora are low, phytophthora-susceptible cultivars could be grown with lower chances for the development of silvering and losses to phytophthora blight. In areas where phytophthora may be extremely destructive, planting a phytophthora-resistant cultivar (which may be more prone to silvering) may be necessary, however, with the adoption of a production system which decreases the chances for silvering development, losses in fruit quality may be reduced.

Assessment of Project Approach and Areas of Further Study:

Areas needing additional study

Along with further research efforts in the effects of production system and cultivar on the development of silvering in bell pepper fruit, longer term studies determining what environmental conditions (i.e. soil temperature, soil moisture) may also affect the development of silvering in maturing fruit are needed and may allow growers to simply adjust their production system along with watering/fertigation program to reduce losses to silvering.

Any opinions, findings, conclusions, or recommendations expressed in this publication are those of the author(s) and do not necessarily reflect the view of the U.S. Department of Agriculture or SARE.