Progress 09/01/08 to 08/31/13
Outputs
Target Audience: Carrot and other vegetable seed producers; the vegetable crop production industry, including large- and small-scale growers, organic specialty crop growers and support industry; plant science researchers in horticulture, plant breeding, plant genetics, plant pathology, nematology, soil science, botany, plant geneticists; and the general public consumers. Changes/Problems: Project was extended one additional year to complete field testing What opportunities for training and professional development has the project provided? Included co-PIs P.W. Simon and P. A. Roberts, J. Nunez, University of California Cooperative Extension, one post-doctoral scientist and two graduate students, and three undergraduate research helpers with the USDA, ARS at the University of Wisconsin – Madison, and with the University of California-Riverside, carrot seed industry and producers. Graduate students, postdoctoral scientist and undergraduate students were extensively trained. The California Fresh Carrot Advisory Board was also involved in undertaking this work. Professional development and training included presenting information to carrot growers groups at meetings and at field days on carrot nematode resistance evaluation trials and carrot hybrid germplasm evaluation trials. Participants from the general public were in attendance in lectures (Wisconsin) and field days (California and Wisconsin) described elsewhere in this report. How have the results been disseminated to communities of interest? During the five field seasons of this project, carrot populations developed from parents representing several sources of resistance were displayed in field trials to evaluate horticultural attributes (appearance, flavor) during USDA – UC Desert Research and Extension Center (DREC) carrot field day all five years (attended by about 50 carrot industry reps and local news media), USDA – UW field day all five years (~20 carrot industry and university students), International Carrot Conferences in CA, WA, and WI (~ 120-200 carrot industry, students, and global researchers) and multi-state conventional and organic trials for two years. Carrot populations were field evaluated for nematode resistance in infested fields and displayed to carrot growers and seed producers at the UC South Coast station three years, and at the UC Kearney station two years (~20 carrot growers and industry reps). Press releases on carrot nematode resistance distributed in conjunction with two field trials attracted media attention in local newspapers; and Carrot Country, the carrot industry magazine, reported extensively on the project and germplasm three times. Oral presentations reporting progress in nematode screening and seed production of resistant selections were delivered at the California Fresh Carrot Advisory Board Meetings all five years to 30-40 carrot growers, shippers, and seed companies representing ~70% of the U.S. production and most of the U.S. growing area with warm climate nematode attack, and at the ASHS Meeting SCRI workshop one year to ~45 plant scientists and with posters two years. Oral presentations and posters were presented at four International Carrot Conferences in CA, WA, WI, and South Africa with ~120 diverse researchers, and crop and seed producers. Posters on nematode resistance and nutritional quality of resistant germplasm were presented by graduate students trained under this project at three National Association of Plant Breeders meetings and two Plant and Animal Genome meetings. Detailed results of the nematode resistance and quality were included all five years in the annual reports of the California Fresh Carrot Advisory Board which is distributed industry-wide. Nematode resistant carrots were featured at the Farm Smart Program at UC DREC in for all five years (>8000 “learners” annually), and the University of Wisconsin Horticultural Field Days three years (>200 participants) where carrot samples were made available for tasting and described in a handout. A web site (http://www.ars.usda.gov/pandp/docs.htm?docid=19858) was developed to target carrot growers and inform the public about carrots and the role nematode resistance will have for the U.S. crop. Regular interactions with industry at these various field and meeting events provided stakeholder input. Reports, photos of carrots & trial results are posted. Regular communications have been established with our advisory team, carrot grower and seed company representatives on our industry stakeholder team, as well as with other carrot growers and seed companies. What do you plan to do during the next reporting period to accomplish the goals?
Nothing Reported
Impacts
What was accomplished under these goals?
Carrots are an important source of nutrients for the U.S. diet and have over $600 million farm gate value to U.S. growers, but over 80% of the U.S. carrot production land is infested with one or more of the common species of root-knot nematodes (Meloidogyne) so that root-knot nematodes threaten approximately at least 3/4 of U.S. carrot crop. Nematode infection causes forking and galling disfiguration to carrot taproots resulting in cosmetic injury and economic loss. New sources of genetic resistance to the two most important root-knot species affecting carrot production, M. javanica and M. incognita, have been identified in several unrelated germplasm sources from local carrot populations of diverse geographic origins. Goals of the project: Project goal is to develop carrots requiring less input for growers, with more flavor and nutritional quality for consumers. In particular, carrots bred to incorporate new genetic resistance to nematodes with improved nutrition, flavor and culinary quality. Progress: With resources of this project (personnel, supplies, and services provided), we were able to evaluate carrots for nematode resistance and nutritional quality, to produce carrot seed of elite lines, to determine the genetic inheritance of nematode resistance, and to develop molecular markers to track the resistance genes. As a result, carrot seed from germplasm sources derived from South American, Middle Eastern, Asian and European carrots was extensively tested in heavily infested fields and greenhouse inoculation trials, stable resistance was confirmed in eight breeding stocks, and the inheritance of resistance was determined to be controlled by six genetic loci, with molecular markers developed for all of these genes. Nutritional quality as reflected by pro-vitamin A carotene content was increased from 20% to 45% while selecting for nematode resistance in these breeding stocks, and flavor was evaluated and selected for increased sweetness and uniformly mild carrot flavor. Seed was developed for distribution to seed companies that represent all of the commercial carrot seed sources used by the U.S. carrot industry including major production regions threatened by root-knot nematodes. A new source of genetic resistance to M. javanica was characterized, and fundamental information elucidating carotene pigment accumulation as it relates to nuclear gene expression and the plastid genome in nematode resistant carrots and other diverse carrots was generated and published. The nematode resistant carrots of Middle Eastern and Asian origin have unusual purple and yellow colored taproots that may open new markets for large-scale and niche market growers. Large-scale seed lots (up to 4kg) of advanced nematode resistant carrot lines were produced by seed industry partners and are in large-scale evaluation trials in nematode-infested commercial production fields as part of the resistant carrot implementation process. Industry feed-back from seed companies has been positive, and testing of their submitted experimental hybrids in heavily infested fields has demonstrated that breeding stock developed by them using our sources of resistance had excellent nematode resistance, acceptable appearance, desirable sweet flavor, and nutritional quality comparable to or exceeding widely-grown nematode susceptible carrots in the market today. In addition to the material outcomes of this project, two graduate students were trained, three undergraduate projects on nematode resistance genetics and nutritional quality were completed, several publications were submitted and are in progress, and as described in outputs, the carrot seed and commercial production industry, as well as the general public was informed about this project.
Publications
- Type:
Websites
Status:
Accepted
Year Published:
2009
Citation:
http://www.ars.usda.gov/pandp/docs.htm?docid=19858
- Type:
Journal Articles
Status:
Accepted
Year Published:
2013
Citation:
Ali A., W.C. Matthews, P.F. Cavagnaro, M. Iorizzo, P.A. Roberts, and P.W. Simon. Inheritance and mapping of Mj-2, a new source of root-knot nematode (Meloidogyne javanica) resistance in carrot. J. Heredity
- Type:
Journal Articles
Status:
Accepted
Year Published:
2013
Citation:
Bowman, M.J., and P.W. Simon. Quantification of the relative abundance of plastome to nuclear genome in leaf and root tissues of carrot (Daucus carota L.) using quantitative PCR. Plant Molecular Biology Reporter 31: 1040-1047. 2013.
- Type:
Journal Articles
Status:
Accepted
Year Published:
2013
Citation:
Bowman, M.J., D.K. Willis, and P.W. Simon. Transcript abundance of phytoene synthase 1 and phytoene synthase 2 is associated with natural variation of storage root carotenoid pigmentation in carrot. J. Amer. Soc. Hort. Sci. 139:16.
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Progress 09/01/11 to 08/31/12
Outputs
OUTPUTS: Carrot populations developed from parents representing several sources of resistance were displayed in field trials during USDA - UC Desert Research and Extension Center (DREC) carrot field day February 28, 2012 (attended by about 50 carrot industry reps and local news media), the annual USDA - UW field day August 23, 2012 (~20 carrot industry and university students), and USDA - UC South Coast Research and Extension Center Field Day Nov. 15, 2012 (~20 carrot growers and industry reps). USDA experimental hybrids including nematode resistant parents had high horticultural quality (appearance and flavor) based on performance evaluated by attendees, and USDA experimental nematode resistant germplasm including resistant parents had high levels of nematode resistance where resistance to two species of root-knot nematode was evaluated. A press release on the USDA - UC DREC trial attracted media attention in the local newspaper. Progress in nematode screening and seed production of resistant selections was discussed at the California Fresh Carrot Advisory Board Meeting March 8, 2012 in Bakersfield to ~40 carrot growers, shippers, and seed companies representing ~70% of the U.S. production and most of the U.S. growing area with warm climate nematode attack; and at the ASHS Meeting SCRI workshop Aug. 2, 2012 in Miami to ~45 plant scientists. Detailed results of the nematode resistance and agronomic screenings were reported in the annual report of the California Fresh Carrot Advisory Board which is distributed industry-wide. Nematode resistant carrots were featured at 1) the Farm Smart Program at UC DREC in January and March, 2012 (>8000 "learners" annually), and the University of Wisconsin Horticultural Field Days in September, 2012 (>200 participants). Carrots were provided, described to the public and samples made available for tasting. A web site (http://www.ars.usda.gov/pandp/docs.htmdocid=19858) is developed to target carrot growers and inform the public about carrots and the role nematode resistance will have for the U.S. crop. Regular interactions with industry provides stakeholder input. Reports, photos of carrots & trial results are posted. Collaborative trials in organic production sites are in place. Regular communications have been established with our advisory team, carrot grower and seed company representatives on our industry stakeholder team, as well as with other carrot growers and seed companies. Large-scale seed lots (up to 4kg) of advanced nematode resistant carrot lines were developed with seed industry partners and are in large-scale evaluation trials under grower production field conditions as part of the resistant carrot implementation process. PARTICIPANTS: Included co-PIs P.W. Simon and P. A. Roberts, J. Nunez, University of California Cooperative Extension, scientists and students with the USDA, ARS at the University of Wisconsin - Madison, and with the University of California-Riverside, carrot seed industry and producers. The California Fresh Carrot Advisory Board was also involved in undertaking this work. Professional development and training included presenting information to carrot growers groups at meetings and at field days on carrot nematode resistance evaluation trials and carrot hybrid germplasm evaluation trials. Participants from the general public were in attendance in lectures (Wisconsin) and field days (California and Wisconsin) described in "Outputs". TARGET AUDIENCES: ncluded carrot seed producers, crop production industry, small-scale and organic specialty crop growers and support industry, vegetable researchers, plant geneticists, and consumers. A web site was developed to inform carrot industry, researchers, and consumers about project progress, and oral and poster presentations were made at crop production, national horticulture, plant breeding, and genomics meetings. PROJECT MODIFICATIONS: Project was extended one year to complete data collection. Will be completed August 2013.
Impacts
Carrots are an important source of nutrients for the U.S. diet and have $550 million farm gate value to U.S. growers, but root-knot nematodes (Meloidogyne spp.) threaten approximately 3/4 of U.S. carrot crop. Nematode infection causes forking and galling disfiguration to carrot taproots resulting in cosmetic injury and economic loss. New sources of genetic resistance to the two most important root-knot species affecting carrot production, M. javanica and M. incognita, have been identified in several unrelated germplasm sources from local carrot populations of diverse geographic origins including Brazil, Europe, Syria, China, and Australia. These sources of nematode resistance vary widely in nutritional value and flavor. This project moves nematode resistant carrots to mainstream production and improves nutritional value of typical orange, nematode resistant carrots. The inheritance and genetic map location of resistance genes is being determined, and molecular markers are being developed to facilitate incorporation of resistance genes by indirect selection. Carrot types with unusual purple and yellow color that occur in resistant germplasm will also be available for large-scale and niche market growers. Progress has been made in achieving the goals of this project according to our proposed plan of work. This year preliminary provision of seed samples of selected resistant inbreds has been made to vegetable seed companies with carrot breeding programs to provide us with information about both field performance of inbreds and experimental hybrids produced by industry, and also seed production capability of this elite germplasm. This also allows initial incorporation of selected resistance genes into industry germplasm, making deployment possible through this vital industry conduit of our public sector-developed elite germplasm. Industry feed-back from five seed companies has been received and positive progress has been noted by them, in terms of ability to generate crosses incorporating both nematode resistance and horticultural field and consumer quality, and in terms of seed production capacity of selected materials. Nutritional quality evaluations have been made based upon carotenoid and anthocyanin pigment levels and types, and promising nutritional value is equivalent to or surpasses average carotene content of major current U.S. carrot cultivars, with typical anthocyanin and lutein content compared to several purple and yellow carrots grown in the U.S. Flavor evaluations indicated flavor comparable to standard U.S. carrots, with exceptional juicy texture noted in some selections.
Publications
- Simon, P.W., and Roberts, P.A. 2012 Deployment of Nutrient-Rich Nematode Resistant. ASHS Meeting Abstracts.
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Progress 09/01/10 to 08/31/11
Outputs
OUTPUTS: Carrot populations developed from parents representing several sources of resistance were displayed in field trials during USDA - UC Desert Research and Extension Center (DREC) carrot field day March 1, 2011 (attended by about 50 carrot industry reps and local news media), the annual USDA - UW field day August 26, 2011 (~20 carrot industry and university students), and USDA - UC Kearney Agr Center Field Day Sept. 15, 2011 (~20 carrot growers and industry reps, and local news media). USDA experimental hybrids including nematode resistant parents had high horticultural quality (appearance and flavor) based on performance evaluated by attendees, and USDA experimental nematode resistant germplasm including resistant parents had high levels of nematode resistance where nematode resistance to two species of root-knot nematode was evaluated. A press release on the USDA - UC DREC trial attracted media attention in the local newspaper. The USDA - UC Kearney trial attracted coverage by the industry trade journal, Carrot Country, which resulted in the major story including cover photo for the Fall, 2011 issue. Progress in nematode screening and seed production of resistant selections was discussed at the California Fresh Carrot Advisory Board Meeting March 15, 2011 in Bakersfield to ~30 carrot growers, shippers, and seed companies representing ~70% of the U.S. production and most of the U.S. growing area with warm climate nematode attack; and the 35th Intl. Carrot Conf. November 30 in South Africa to ~140 carrot growers, processors, and seed companies. Detailed results of the nematode resistance and agronomic screenings were reported in the annual report of the California Fresh Carrot Advisory Board which is distributed industry-wide. Nematode resistant carrots were featured at 1) the Farm Smart Program at UC DREC in January and March, 2011 (>8000 "learners" annually), and the University of Wisconsin Horticultural Field Days in September, 2011 (>200 participants). Carrots were provided, described to the public and samples made available for tasting. A lecture ocarrots that included several images of nematode resistant carrots and this project, was presented at "Wednesday Night at the Lab", a UW public science education program with ~80 attendees from the public, videostreaming at WHA, the Wisconsin Public Television network, and broadcast 4x. A web site (http://www.ars.usda.gov/pandp/docs.htmdocid=19858) is developed to target carrot growers and inform the public about carrots and the role nematode resistance will have for the U.S. crop. Regular interactions with industry provides stakeholder input. Reports, photos of carrots & trial results are posted. Collaborative trials in organic production sites are in place. Regular communications have been established with our advisory team, carrot grower and seed company representatives on our industry stakeholder team, as well as with other carrot growers and seed companies. Large-scale seed lots (up to 4kg) of advanced nematode resistant carrot lines were developed with seed industry partners for evaluation under grower production field conditions as part of the resistant carrot implementation process. PARTICIPANTS: Included co-PIs P.W. Simon and P. A. Roberts, J. Nunez, University of California Cooperative Extension, scientists and students with the USDA, ARS at the University of Wisconsin - Madison, and with the University of California-Riverside, carrot seed industry and producers. The California Fresh Carrot Advisory Board was also involved in undertaking this work. Professional development and training included presenting information to carrot growers groups at meetings and at field days on carrot nematode resistance evaluation trials and carrot hybrid germplasm evaluation trials. Participants from the general public were in attendance in lectures (Wisconsin and South Africa) and field days (California and Wisconsin) described in "Outputs". TARGET AUDIENCES: Included carrot seed producers, crop production industry, small-scale and organic specialty crop growers and support industry, vegetable researchers, plant geneticists, and consumers. A web site was developed to inform carrot industry, researchers, and consumers about project progress, and oral and poster presentations were made at crop production, national horticulture, plant breeding, and genomics meetings. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.
Impacts
Carrots are an important source of nutrients for the U.S. diet and have $550 million farm gate value to U.S. growers, but root-knot nematodes (Meloidogyne spp.) threaten approximately 3/4 of U.S. carrot crop. Nematode infection causes forking and galling disfiguration to carrot taproots resulting in cosmetic injury and economic loss. New sources of genetic resistance to the two most important root-knot species affecting carrot production, M. javanica and M. incognita, have been identified in several unrelated germplasm sources from local carrot populations of diverse geographic origins including Brazil, Europe, Syria, China, and Australia. These sources of nematode resistance vary widely in nutritional value and flavor. This project moves nematode resistant carrots to mainstream production and improves nutritional value of typical orange, nematode resistant carrots. The inheritance and genetic map location of resistance genes is being determined, and molecular markers are being developed to facilitate incorporation of resistance genes by indirect selection. Carrot types with unusual purple and yellow color that occur in resistant germplasm will also be available for large-scale and niche market growers. Progress has been made in achieving the goals of this project according to our proposed plan of work. This year preliminary provision of seed samples of selected resistant inbreds has been made to vegetable seed companies with carrot breeding programs to provide us with information about both field performance of inbreds and experimental hybrids produced by industry, and also seed production capability of this elite germplasm. This also allows initial incorporation of selected resistance genes into industry germplasm, making deployment possible through this vital industry conduit of our public sector-developed elite germplasm. Industry feed-back from five seed companies has been received and positive progress has been noted by them, in terms of ability to generate crosses incorporating both nematode resistance and horticultural field and consumer quality, and in terms of seed production capacity of selected materials. Nutritional quality evaluations have been made based upon carotenoid and anthocyanin pigment levels and types, and promising nutritional value is equivalent to or surpasses average carotene content of major current U.S. carrot cultivars, with typical anthocyanin and lutein content compared to several purple and yellow carrots grown in the U.S. Flavor evaluations indicated flavor comparable to standard U.S. carrots, with exceptional juicy texture noted in some selections.
Publications
- Simon, P.W., and Roberts, P.A. 2011 Deployment of Nutrient-Rich Nematode Resistant. 35th Intl Carrot Conference Meeting Abstracts, p. 3.
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Progress 09/01/09 to 08/31/10
Outputs
OUTPUTS: Carrot populations developed from parents representing several sources of resistance were displayed in field trials during USDA - UC Desert Research and Extension Center (DREC) carrot field day March 1, 2011 (attended by about 50 carrot industry reps and local news media), the annual USDA - UW field day August 26, 2011 (~20 carrot industry and university students), and USDA - UC Kearney Agr Center Field Day Sept. 15, 2011 (~20 carrot growers and industry reps, and local news media). USDA experimental hybrids including nematode resistant parents had high horticultural quality (appearance and flavor) based on performance evaluated by attendees, and USDA experimental nematode resistant germplasm including resistant parents had high levels of nematode resistance where nematode resistance to two species of root-knot nematode was evaluated. A press release on the USDA - UC DREC trial attracted media attention in the local newspaper. The USDA - UC Kearney trial attracted coverage by the industry trade journal, Carrot Country, which resulted in the major story including cover photo for the Fall, 2011 issue. Progress in nematode screening and seed production of resistant selections was discussed at the California Fresh Carrot Advisory Board Meeting March 15, 2011 in Bakersfield to ~30 carrot growers, shippers, and seed companies representing ~70% of the U.S. production and most of the U.S. growing area with warm climate nematode attack; and the 35th Intl. Carrot Conf. November 30 in South Africa to ~140 carrot growers, processors, and seed companies. Detailed results of the nematode resistance and agronomic screenings were reported in the annual report of the California Fresh Carrot Advisory Board which is distributed industry-wide. Nematode resistant carrots were featured at 1) the Farm Smart Program at UC DREC in January and March, 2011 (>8000 "learners" annually), and the University of Wisconsin Horticultural Field Days in September, 2011 (>200 participants). Carrots were provided, described to the public and samples made available for tasting. A lecture ocarrots that included several images of nematode resistant carrots and this project, was presented at "Wednesday Night at the Lab", a UW public science education program with ~80 attendees from the public, videostreaming at WHA, the Wisconsin Public Television network, and broadcast 4x. A web site (http://www.ars.usda.gov/pandp/docs.htmdocid=19858) is developed to target carrot growers and inform the public about carrots and the role nematode resistance will have for the U.S. crop. Regular interactions with industry provides stakeholder input. Reports, photos of carrots & trial results are posted. Collaborative trials in organic production sites are in place. Regular communications have been established with our advisory team, carrot grower and seed company representatives on our industry stakeholder team, as well as with other carrot growers and seed companies. Large-scale seed lots (up to 4kg) of advanced nematode resistant carrot lines were developed with seed industry partners for evaluation under grower production field conditions as part of the resistant carrot implementation process. PARTICIPANTS: Included co-PIs P.W. Simon and P. A. Roberts, J. Nunez, University of California Cooperative Extension, scientists and students with the USDA, ARS at the University of Wisconsin - Madison, and with the University of California-Riverside, carrot seed industry and producers. The California Fresh Carrot Advisory Board was also involved in undertaking this work. Professional development and training included presenting information to carrot growers groups at meetings and at field days on carrot nematode resistance evaluation trials and carrot hybrid germplasm evaluation trials. Participants from the general public were in attendance in lectures (Wisconsin and South Africa) and field days (California and Wisconsin) described in "Outputs". TARGET AUDIENCES: Included carrot seed producers, crop production industry, small-scale and organic specialty crop growers and support industry, vegetable researchers, plant geneticists, and consumers. A web site was developed to inform carrot industry, researchers, and consumers about project progress, and oral and poster presentations were made at crop production, national horticulture, plant breeding, and genomics meetings. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.
Impacts
Carrots are an important source of nutrients for the U.S. diet and have $550 million farm gate value to U.S. growers, but root-knot nematodes (Meloidogyne spp.) threaten approximately 3/4 of U.S. carrot crop. Nematode infection causes forking and galling disfiguration to carrot taproots resulting in cosmetic injury and economic loss. New sources of genetic resistance to the two most important root-knot species affecting carrot production, M. javanica and M. incognita, have been identified in several unrelated germplasm sources from local carrot populations of diverse geographic origins including Brazil, Europe, Syria, China, and Australia. These sources of nematode resistance vary widely in nutritional value and flavor. This project moves nematode resistant carrots to mainstream production and improves nutritional value of typical orange, nematode resistant carrots. The inheritance and genetic map location of resistance genes is being determined, and molecular markers are being developed to facilitate incorporation of resistance genes by indirect selection. Carrot types with unusual purple and yellow color that occur in resistant germplasm will also be available for large-scale and niche market growers. Progress has been made in achieving the goals of this project according to our proposed plan of work. This year preliminary provision of seed samples of selected resistant inbreds has been made to vegetable seed companies with carrot breeding programs to provide us with information about both field performance of inbreds and experimental hybrids produced by industry, and also seed production capability of this elite germplasm. This also allows initial incorporation of selected resistance genes into industry germplasm, making deployment possible through this vital industry conduit of our public sector-developed elite germplasm. Industry feed-back from five seed companies has been received and positive progress has been noted by them, in terms of ability to generate crosses incorporating both nematode resistance and horticultural field and consumer quality, and in terms of seed production capacity of selected materials. Nutritional quality evaluations have been made based upon carotenoid and anthocyanin pigment levels and types, and promising nutritional value is equivalent to or surpasses average carotene content of major current U.S. carrot cultivars, with typical anthocyanin and lutein content compared to several purple and yellow carrots grown in the U.S. Flavor evaluations indicated flavor comparable to standard U.S. carrots, with exceptional juicy texture noted in some selections.
Publications
- Simon, P.W., and Roberts, P.A. 2011 Deployment of Nutrient-Rich Nematode Resistant. 35th International. Carrot Conference Meeting Abstracts, p. 3.
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Progress 09/01/08 to 08/31/09
Outputs
OUTPUTS: Inbred lines, single cross hybrids, and diverse populations from several sources of resistance have been developed and evaluated on a small scale in field test sites heavily infested with nematodes. Plants with superior levels of resistance have been selected and seed supplies of selected individual plants with elite high resistance were increased in collaboration with industry cooperators to provide adequate seed for larger scale testing in the upcoming year. Advanced Brazilian and Syrian resistance sources are in seed production trials to increase seed quantities to a level adequate to allow medium-scale field testing of resistance on grower fields within a year. Seed companies and both large-and small-scale growers are involved in testing these improved carrot populations and hybrids. A web site is being developed to target large and small-scale carrot growers, and regular interactions with crop production and seed production industry personnel provide stakeholder input as a part of this project. Collaborative trials in organic production sites are in place this year with harvest expected soon. Regular communications have been established with carrot grower and seed company representatives on our industry stakeholder team, as well as with other carrot growers and seed companies. PARTICIPANTS: Included co-PIs P.W. Simon and P. A. Roberts, J. Nunez, University of California Cooperative Extension, scientists and students with the USDA, ARS at the University of Wisconsin - Madison, and with the University of California-Riverside, carrot seed industry and producers. The California Fresh Carrot Advisory Board was also involved in undertaking this work. Professional development and training included presenting information to carrot growers groups at meetings and at field days in carrot nematode resistance evaluation trial and carrot hybrid germplasm evaluation trial. TARGET AUDIENCES: Includes carrot seed producers, crop production industry, small-scale and organic specialty crop growers and support industry, vegetable researchers, plant geneticists, and consumers. A web site was developed to inform industry, researchers, and consumers about project progress, and oral and poster presentations were made at crop production meetings, national horticulture, plant breeding, and genomics meetings. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.
Impacts
Carrots are an important source of nutrients for the U.S. diet and have $550 million farm gate value to U.S. growers, but root-knot nematodes (Meloidogyne spp.) threaten approximately 3/4 of U.S. carrot crop. Nematode infection causes forking and galling disfiguration to carrot taproots resulting in cosmetic injury and economic loss. New sources of genetic resistance to the two most important root-knot species affecting carrot production, M. javanica and M. incognita, have been identified in several unrelated germplasm sources from local carrot populations of diverse geographic origins including Brazil, Europe, Syria, China, and Australia. These sources of nematode resistance vary widely in nutritional value attributable to both carotenoid and anthocyanin pigments, and also vary in flavor. This project is moving nematode resistant carrots into mainstream production and also improving nutritional value of typical orange, nematode resistant carrots. The inheritance and genetic map location of resistance genes is being determined, and molecular markers are being developed to facilitate incorporation of resistance genes by indirect selection. Carrot types with unusual purple and yellow colored taproots that occur in resistant germplasm will also be available for large-scale and niche market growers. Progress has been made in achieving the goals of this project according to our proposed plan of work. Extensive evaluation of the strength of the nematode resistance has been made at two infested field screening sites, and in greenhouse screening, with extreme nematode pressure. The resistance from original Brazilian sources as well as a new source of resistance derived from a Syrian carrot was found to hold up very well. Other sources of resistance identified several years ago are still being evaluated and hold some promise. A new source of resistance from a wild carrot is also being evaluated to determine gene action. Nutritional quality evaluations have been made based upon carotenoid and anthocyanin pigment levels and types, and promising nutritional value is evident. Flavor evaluations indicated promising organoleptic quality as well.
Publications
- Simon, P.W., and Roberts, P.A. 2010. Deployment of Nutrient-Rich Nematode Resistant Carrots to Benefit Growers, Consumers, and the Environment (SCRI). HortScience Meeting Abstracts: 51-52.
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