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United States Department of Agriculture

Agricultural Research Service

Research Project: CONSERVATION AND CHARACTERIZATION OF GERMPLASM OF SELECTED VEGETABLE CROPS

Location: Plant Genetic Resources

2012 Annual Report


1a.Objectives (from AD-416):
1. Strategically expand the genetic diversity in genebank collections and improve associated information for priority buckwheat, tomato, cole crops, bulb and bunching onions, and other specialty vegetable crops (celery, radish, asparagus, winter squash, and tomatillo) and their wild relatives.

2. Conserve and regenerate priority buckwheat, tomato, cole crop, bulb and bunching onion, and other specialty vegetable crop (celery, radish, asparagus, winter squash, and tomatillo) genetic resources efficiently and effectively, and distribute pathogen-tested samples (whenever feasible) and associated information worldwide.

3. Strategically characterize (“genotype”) and evaluate (“phenotype”) priority buckwheat, tomato, cole crop, bulb and bunching onion, and other specialty vegetable crop (celery, radish, asparagus, winter squash, tomatillo) genetic resources for molecular markers and highly heritable horticultural and morphological traits.


1b.Approach (from AD-416):
The objectives of this project will be met by a) expanding the genetic diversity in genebank collections and improving associated information for priority buckwheat, tomato, cole crops, bulb and bunching onions, and other specialty vegetable crops (celery, radish, asparagus, winter squash, and tomatillo) and their wild relatives, b) conserving and regenerating genetic resources of these taxa efficiently and effectively, and distributing pathogen-tested samples (whenever feasible) and associated information worldwide, and c) characterizing (“genotype”) and evaluating (“phenotype”) genetic resources of these taxa for molecular markers and highly heritable horticultural and morphological traits. In the next five years the major activities of the project will emphasize upgrading standards for viability and number of seed stored in the active and base collections. Characterization for minimal descriptor lists will be completed for tomatoes, Crucifers, and onions. The primary link with users will be through Crop Germplasm Committees that define crop priorities for collection and evaluation.


3.Progress Report:
In addition to standard characterization, 52 tomato lines representing varieties from five different decades as determined by dates for Plant Variety Protection Certificates were grown in Geneva, NY in 2011 for evaluation. These accessions were evaluated for fruit nutritional traits and morphology. In addition, we collaborated with Research Chemist (USDA-ARS) for performing high performance liquid chromatography of fruit samples which will be used for identification and measurement of nitrogen-containing metabolites. These compounds regulate chemical processes and influence fruit ripening and fruit quality in various crops and are an important class of natural products that contribute to quality and utilization and include essential nutrients that can influence mood and mental well-being. Data from the two years will be analyzed in the upcoming fiscal year.

Inferior flavor is one of the most commonly heard complaints associated with modern varieties of tomato. In collaboration with North Carolina State University 173 accessions from the PGRU tomato core collection were evaluated for odor, taste, flavor, texture and related components including soluble solids and titratable acidity. Overall flavor was analyzed with respect to other traits including fruit firmness, color parameters, lycopene and vitamin C. Information obtained from this study will be useful for tomato breeders aiming to improve tomato flavor.

Tomatillo has been rising in consumption in the U.S. with increased influence of Mexican and Latin American cuisines. Very few molecular genetic or genomic resources have been developed for this crop. We resequenced 14 tomato markers (gene fragments) in five inbred lines of PGRU tomatillo accessions. We found a moderate degree of transferability of markers between tomato and tomatillo. We are now working on optimizing next-generation sequence based markers (genotyping by sequencing, GBS) tomato and tomatillo

Wild tomato Lycopersicon peruvianum has been reclassified into four new Solanum spp. taxa. We have isolated DNA from 12 PGRU accessions of each of the four species. We are now working on optimizing and applying GBS to these DNA samples. Data will be used to estimate diversity and gene flow within and among species, and to develop species diagnostic markers.


4.Accomplishments
1. Maintained genetic resources of vegetables for crop improvement and research. Genetic resources are the diverse plant varieties and lines maintained in a collection that provide the genes needed for crop improvement and research. Worldwide, vegetable breeders and other researchers need a ready source of genes to use to provide new vegetable varieties that have disease and pest resistance, tolerance to abiotic stresses, increased quality, and improved nutrition. ARS researchers at Geneva, New York maintained approximately 12,485 accessions of tomato, onion, radish, winter squash, cabbage, cauliflower, broccoli, other cole crops, celery, tomatillo, asparagus and other vegetables for the long-term and 2 new accessions of onion were acquired. This provided the genetic diversity needed to develop vegetable varieties with disease and pest resistance, tolerance to abiotic stresses, and varieties with improved quality and nutrition; and ensured its future availability in the long-term.

2. Ensuring sufficient quantities of seed of vegetable genetic resources are available for distribution. There is a continuing need for regeneration of vegetable varieties, wild plants, and researcher’s lines to have seed available for crop researchers that provide necessary genes for crop improvement and research. This is due to loss of viability over time and the usage of seed as it is distributed for crop improvement and research. During FY 2012 approximately 295 accessions were regenerated by ARS researchers at Geneva, New York and 32 accessions of short day onions were regenerated at New Mexico State University through a cooperative agreement, and 12 accessions of long day onions were regenerated at Nunhems Inc. through a cooperative agreement; additionally, 113 biennial crop accessions were grown to produce plants for use in seed production in 2012. This allowed us to continue to distribute seed; 10,003 seed lots of 7,989 accessions were distributed in 295 orders (240 domestic and 55 foreign). This germplasm is available for use by qualified researchers and other bona fide users worldwide.


Review Publications
Panthee, D., Cao, C., Debenport, S., Rodriguez, G., Labate, J.A., Robertson, L.D., Breksa Iii, A.P., Van Der Knaap, E., Mcspadden-Gardener, B. 2012. Magnitude of genotype x environment interactions affecting tomato fruit quality. HortScience. 47:721-726.

Last Modified: 4/18/2014
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