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United States Department of Agriculture

Agricultural Research Service

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Research Project: THE NEXT STEP IN CAPSICUM GERMPLASM RESOURCE DEVELOPMENT: VIRUS FREE C. FTUTESCENS ACCESSIONS AND CAPSAICINOID ANALYSIS OF C. BACCATUM STOCK

Location: Plant Genetic Resources Conservation Unit

2013 Annual Report


1a.Objectives (from AD-416):
1. The production of capsaicinoid profiles (UPLC-MS) of ~350 genebank accessions of Capsicum baccatum.

2. The elimination of PMMoV from 89 infested and 17 untested accessions of Capsicum frutescens from the USDA genebank.

3. The production of clean selfed seed from these and an additional 32 uninfested C. frutescens accessions.


1b.Approach (from AD-416):
Greenhouse selfed (virus-free) seed, descriptor data and capsaicinoid profiles will be made available to the NPGS Vegetable Crops Curator.

Three hundred and fifty fruit samples of Capsicum baccatum prepared previously will be extracted and analyzed via UPLC-MS to produce capsaicinoid profiles. Seed (inbred) of these accessions will be shared with the USDA genebank. Virus will be eradicated from infected C. frutescens seed lots as follows: Seed of PMMoV-infected accessions will be treated with 10% trisodium phosphate for 2 hours and rinsed. Seedlings will be screened for the presence of PMMoV coat protein by ELISA and rescreened after transplanting. Thirty-two uninfected accessions will also be included. For all accessions, plants representing each morphological type observed will be transplanted to the greenhouse and selfed seed produced from them.


3.Progress Report:

Germplasm development in Capsicum is conducted in support of inhouse project #6607-21000-011-00D Objective 3: Conduct genetic characterizations and phenotypic evaluations for the preceding crops and related wild species for priority genetic and agronomic traits.

In 2012 we received all available accessions (260) of the Capsicum frutescens collection. Seed of these were treated and seedlings were confirmed to be free of Pepper mild mottle virus (PMMoV) by immunostrip testing. One PMMoV positive seedling was found and removed from the population. Neighboring seedlings were removed or retested after 10 days. Transplants were set in the field in black plastic mulch with drip irrigation and single plant selections were made in the fall and transferred to the greenhouse. Several accessions were obviously other species such as C. baccatum and C. annuum. Fruit and flower photos were taken and seed were collected. Unfortunately, the greenhouse workers spread TMV from a tomato planting to the peppers. We will regenerate clean seed to share with the NPGS from these stocks and request new stocks of those where seed was not collected due to observation of TMV infection of plants before harvest. HPLC analysis of previously collected C. baccatum fruit was performed and data are currently being error checked for proper peak assignment.

In regards to other activities, we have been able to follow up on past projects and initiate a new one. We received approximately half the C. chinense collection inclusive of all the PMMoV infested accessions. These were treated and largely found to be negative, and despite some germination issues most were able to be transplanted to the field for single plant selections. We were able to complete our work with the C. baccatum collection with the release of Tomato Analyzer 3, that provided a stable platform for image analysis of fruit sections. These data are complete and ready to share with the NPGS.


Last Modified: 7/28/2014
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