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Bjorkman, Thomas Nils Erik
Cornell Faculty Member
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Positions
- Associate Professor, Horticulture (HORT), College of Agriculture and Life Sciences (CALS)
My research covers the range from discovering basic biological principles, to direct application in commercial settings. I study the effects of environmental stimuli on growth and development, particularly as applied to vegetable production. Current work in flowering includes discovering how temperature regulates the transition from inflorescence to flower in broccoli using the tools of functional genomics. I also have a strong interest in improving agricultural production through better integration, including work on cover crops that fill management goals for vegetable producers. Cover crops have physiological processes with valuable management benefits that complement the needs of vegetable growers. I am leading two multi-state research and extension teams. One seeks to make summer cover crops a standard practice on organic vegetable farms in the Great Lakes region. The other will establish a year-round Eastern broccoli industry by developing commercial varieties from existing germplasm that tolerates our growing conditions, developing grower networks in six Eastern locations that can collectively provide year-round harvest, and developing a distribution network to serve major Eastern markets.
Research Areas
- Affiliations
- Extension
- Research
- Publications
- Teaching
- Service
- Background
- Other
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Affiliations
other Cornell affiliations
member of
- David R. Atkinson Center for a Sustainable Future (ACSF) Faculty Fellow
Extension
has primary specialization area
has secondary specialization area
Research
research overview
- A major are of applied research is in the mechanism whereby cover crops can overcome limitations in soil quality and contribute to weed management in vegetable production systems. Significant funding was obtained in 2009 to develop multi-institutional programs to this end. My basic research focuses on how development is arrested in the inflorescence of Brassica oleracea. A superb model system for this process is broccoli, a close relative of the well-studied Arabidopsis, and, with cauliflower, an extreme expression of such developmental arrest. Furthermore, precise control of this arrest is a critical management issue for a billion-dollar part of the vegetable industry. My lab investigates the role of homeotic genes believed to control developmental transition during this process. My related applied research involves facilitating selection for broccoli that consistently avoids premature arrest that is normally induced by high temperatures during the main growing season. Major funding was received in 2010 for and integrated project to establish an eastern broccoli industry based on new varieties derived from these selections.
research activities
- Broccoli, a new high-value vegetable for New York
- Enhancing science education in rural New York
- Improving phosphorus management in vegetable production
- Providing vegetable growers with tools for weed control
- Revitalizing a traditional New York specialty crop
- Summer cover crops for weed management in vegetable production
principal investigator on
- EASTERN BROCCOLI: DEVELOPING AN EASTERN BROCCOLI INDUSTRY awarded by NATIONAL INSTITUTE OF FOOD AND AGRICULTURE-USDA 2010 - 2015
- FILLING SOIL HEALTH PRESCRIPTIONS WITH TARGETED COVER CROP awarded by NATIONAL INSTITUTE OF FOOD AND AGRICULTURE-USDA 2009 - 2013
- SUMMER COVER CROPS FOR WEED SUPPRESSION AND SOIL QUALITY IN ORGANIC VEGETABLE PRODUCTION IN THE GREAT LAKES REGION awarded by NATIONAL INSTITUTE OF FOOD AND AGRICULTURE-USDA 2009 - 2013
area(s) of concentration/expertise
keywords
- cover crops
- organic agriculture
- plant physiology
- plant science
- reproductive development
geographic focus
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domestic geographical region
submitted impact statement
Publications
individual publications
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web resource
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academic article
- Soaking temperature of dried tuberous roots influences hydration kinetics and growth of Ranunculus asiaticus (L.).. HortScience. 47:212-216. 2012
- Trichoderma harzianum enhances antioxidant defense of tomato seedlings and resistance to water deficit. . Molecular Plant Microbe Interactions. 25:1264-1271. 2012
- Breeding Vegetables Adapted to High Temperatures: A Case Study with Broccoli . HortScience. 46:1093-1097. 2011
- Evaluation of experimental broccoli hybrids developed for summer production in the Eastern United States. HortScience. 46:858-863. 2011
- Seed treatments with Trichoderma harzianum alleviate biotic, abiotic and physiological stresses in germinating seeds and seedlings. Phytopathology. 100:1213-1221. 2010
- Buckwheat cover crops for vegetable rotations to reduce weeds and improve soil condition. HortScience. 43:1139. 2008
- Changing paradigms on the mode of action and uses of Trichoderma spp for biocontrol. Outlooks in Pest Management. 19:24-29. 2008
- Meristem gene expression during reproductive development in Brassica oleracea. Journal of Experimental Botany. 59:421-433. 2008
- Rye Mulch Management Affects Short-term Indicators of Soil Quality in the Transition to Conservation Tillage for Cabbage. HortScience. 43:862-867. 2008
- Overcoming Compaction Limitations on Cabbage Growth and Yield in the Transition to Conservation Tillage. HortScience. 42:1690-1694. 2007
- Establishment of buckwheat as a summer cover crop after early vegetables. HortScience. 41:1063. 2006
- Inflorescence Identity Gene Alleles Are Poor Predictors of Inflorescence Type in Broccoli and Cauliflower. Journal of American Society of Horticultural Science. 131:667-673. 2006
- Meristem identity genes and the control of reproductive development in Brassica oleracea. HortScience. 41:973. 2006
- Temperature effects on meristem identity genes controlling the reproductive development of cauliflower (Brassica oleracea var. botrytis) and broccoli (Brassica oleracea var. italica). HortScience. 40:1015. 2005
- Effect of Trichoderma colonization on auxin-mediated regulation of root elongation. Plant Growth Regulation. 43:89-92. 2004
- High-quality social analysis. California Agriculture. 58:4. 2004
- Genotypes at the BoCAL-a locus in B. oleracea do not predict broccoli cauliflower and purple cauliflower phenotype. HortScience. 38:736. 2003
- Dose and timing of brushing to control excessive hypocotyl elongation in cucumber transplants. HortTechnology. 9:40-42. 1999
- Field performance of tomato transplants treated with mechanical conditioning. HortScience. 34:848-851. 1999
- Solubilization of phosphates and micronutrients by the plant-growth promoting and biocontrol fungus Trichoderma harzianum Rifai strain 1295-22. Applied and Environmental Microbiology. 65:2926-2933. 1999
- Growth enhancement of shrunken-2 (sh2) sweet corn by Trichoderma harzianum 1295-22: Effect of environmental stress. Journal of American Society of Horticultural Science. 123:35-40. 1998
- High temperature arrest of inflorescence development in broccoli (Brassica oleracea var. italica L). Journal of Experimental Botany. 49:101-106. 1998
- Mechanical conditioning for controlling excessive elongation in transplants. Journal of the Japanese Society for Horticultural Science. 67:1121-1123. 1998
- The Role of honeybees (Order: Hymenoptera) in the pollination of buckwheat (Family: Polygonaceae). Journal of Economic Entomology. 88:1739-1745. 1995
- The effect of pollen load and pollen grain competition in fertilization success and progeny performance in Fagopyrum esculentum. Euphytica. 83:47-52. 1995
- The effectiveness of heterostyly in preventing illegitimate pollination in dish-shaped flowers. Sexual Plant Reproduction. 8:143-146. 1995
- Variation in pollen performance among plants of Fagopyrum esculentum. Euphytica. 82:235-240. 1995
- Perception of gravity by plants. Advances in Space Research. 12:195-201. 1992
- Extracellular calcium in gravitropic signalling in maize roots. Planta. 185:379-385. 1991
- Root growth regulation and gravitropism in maize roots does not require the epidermis. Planta. 185:34-37. 1991
- The use of bioelectric currents to study gravity perception in roots. Biological Bulletin. 176S:49-55. 1989
- The perception of gravity in plants. Advances in Botanical Research. 15:1-41. 1988
- The role of the cortex and epidermis in maize root gravitropism. Planta. 176:513-518. 1988
- An electric current associated with gravity sensing in maize roots. Plant Physiology. 84:841-847. 1987
- Effect of inhibitors of auxin transport and of calmodulin on a gravisensing-dependent current in maize roots. Plant Physiology. 84:847-851. 1987
- Field properties and ion uptake of wheat and oat: are they expressed in the modulatory influences of ions on membrane ATPases?. Oikos: A Journal of Ecology. 40:6-13. 1983
- Inhibition of divalent-cation activated adenosine triphosphatase from the microsomal fraction of wheat roots. Acta Chemica Scandinavica. B34:5-6. 1980
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article
- Cover crop options if the soil is too dry for fast establishment 2011
- Another way to improve your ground after harvesting early vegetables: Teff 2010
- Cover crop management in May 2010
- June is the time for Sudangrass cover crops 2010
- Know Your Crucifer Cover Crops 2010
- Spring planted mustard cover crops 2010
- Spring planted mustard cover crops.. Veg Edge. :1. 2010
- Northeast Buckwheat Growers Association Newsletter 2009
- A decision tool to help New York vegetable growers easily pick the best cover crop 2008
- Buckwheat for summer cover crops 2008
- Choosing a Cover Crop - New Decision Tool 2008
- Northeast Buckwheat Growers Association Newsletter 2008
- Northeast Buckwheat Growers Association Newsletter 2008
- Organic fertility recommendations 2008
- Selecting the right cover crop 2008
- Summer broccoli 2008
- Bringing new land into production? A well timed cover crop saves later headaches 2007
- Strawberry Weed Management with Buckwheat Cover Crops 2007
- Floral morphology of 'Anand' Rapid Cycling Brassica oleracea 2003
- Production Guide for Buckwheat in the Northeast. The Birkett Mills. . 2000
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chapter
- Potential and existing uses of Trichoderma and Gliocladium for plant disease control and plant growth enhancement. Trichoderma and Gliocladium. 229-265. 1998
- Potential and existing uses of Trichoderma and Gliocladium for plant disease control and plant growth enhancement. Trichoderma and Gliocladium. Enzymes, biological control and commercial applications. 229-266. 1998
- Root colonization and growth responses to an improved biocontrol fungus. Radical biology: advances and perspectives on the function of plant roots. 532-534. 1998
- Pollen competition in buckwheat. Pollen-pistil interactions and pollen tube growth. 280-283. 1994
- Calcium, cell walls and growth. Calcium in plant growth and development. 1990
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conference paper
- A transdisciplinary approach to developing an eastern broccoli Industry.. HortScience (Abstr.). 2012
- Performance of current broccoli varieties under eastern US conditions.. HortScience (Abstr.). 2012
- Expansion of the Eastern Broccoli Industry. New England Vegetable and Fruit Conference. 2011
- Pea and Bean Crop Rotations with Buckwheat. New England Vegetable and Fruit Conference. 2011
- Mustard Suppression of Cucurbits without Biofumigation. American Society for Horticultural Sciences. 27. 2010
- Trichoderma–Plant Association Enhances Plant Antioxidant Capacity and Tolerance to Abiotic Stresses. American Society for Horticultural Sciences. 16. 2010
- Many shades of black: cabbage storage disorders. NYS Vegetable Conference Proceedings. 39-40. 2002
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document part
- Control of weed size by compost application rate in an organic cropping system 2010
- Heavy fertilization with compost and manure can cause weed problems 2010
- An online cover crop decision tool to quickly choose the right cover crop. 1099-1100. 2009
- Control of weed size by compost application rate in an organic cropping system 2008
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manual
- Organic fertility recommendations. 65-80. 2008
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report
- Causes of poor stand establishment after heavy rains. 134-137. 2001
- Forage Radishes 2011
- Buckwheat Production: Harvesting 2010
- Buckwheat Production: Planting 2010
- Extension Fact Sheet 2010
- 2009 Production Guide for Organic Beans for Processing 2009
- 2009 Production Guide for Organic Cole Crops 2009
- Buckwheat cover crop handbook 2008
presentations
featured in archived article
Teaching
teaching activities
- HORT-9900: Thesis Research, Doctor of Philosophy - Spring 2013
- AGSCI-4960: Internship in Agricultural Sciences - Fall 2012
- HORT-9900: Thesis Research, Doctor of Philosophy - Fall 2012
- HORT-9900: Thesis Research, Doctor of Philosophy - Spring 2012
- AGSCI-4960: Internship in Agricultural Sciences - Fall 2011
- HORT-9900: Thesis Research, Doctor of Philosophy - Fall 2011
Service
outreach overview
- I am the primary contact for cover crop use in vegetable production. The intensity of vegetable production necessitates active soil improvement regimes. Cover crops play an essential role in soil improvement as well as pest and weed management and biological nitrogen fertilization. Introduction of cover crops requires a systemic analysis of production systems, their constraints and limitations. Outreach on soil improving aspects are designed to fill prescriptions produced by the Cornell Soil Health Test. This work is particularly valued by the rapidly growing organic industry. Current new outreach activity focuses on the use of short cycle cover crops during the growing season, which is a useful practice for which guidelines have not yet been established. Supporting my extension work, I do applied research on physiology of summer cover crops in relation to their competitiveness against weeds, and their ability to improve soil condition. I also lead the extension for buckwheat grain production, and am a resource for non-pathogenic storage disorders in cabbage.
service to the profession
- USDA Multistate Project NE-1047 Member 2011 -
- USDA Multistate Project SCC-083 Member 2010 -
- American Society for Horticultural Sciences, National Issues Task Force Chairperson 2007 -
- Cornell Cooperative Extension Vegetable Crop Program Work Team Member 2004 -
- American Society of Plant Biologists
- Crop Physiology Working Group, American Society for Horticultural Sciences
- International Buckwheat Research Association
- Cornell Cooperative Extension Vegetable Crop Program Work Team Chairperson 2009 - 2012
- USDA Multistate Project NE-1026 Member 2007 - 2012
- Sigma Xi Officer, President/Elect/Past 2009 - 2010
- Research Advisory Council, American Society for Horticultural Sciences Member 2005 - 2010
- Scandinavian Society for Plant Physiology Member 1980 - 2010
- Scientific Committee Brassica 2008, International Society for Horticultural Sciences Member - 2008
- AI-SPER-0203DF692AB00010817 Board of Advisors 2008
Background
education and training
- Ph.D. in Botany, Cornell University 1987
- B.S. in Biochemistry, University of California, Davis 1979
awards and honors
Other
college
- CALS
research keyword
- cover crops
- organic agriculture
- plant physiology
- plant science
- reproductive development