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United States Department of Agriculture

Agricultural Research Service

Research Project: NEW CROPS AND MANAGEMENT STRATEGIES TO IMPROVE CROPPING EFFICIENCY IN SHORT-SEASON HIGH-STRESS ENVIRONMENTS

Location: Soil Management Research

Title: Seed germination of calendula in response to temperature

Authors
item EBERLE, CARRIE
item FORCELLA, FRANK
item GESCH, RUSSELL
item PETERSON, DEAN
item EKLUND, JAMES

Submitted to: Industrial Crops and Products
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: October 18, 2013
Publication Date: January 1, 2014
Repository URL: http://handle.nal.usda.gov/10113/58301
Citation: Eberle, C.A., Forcella, F., Gesch, R.W., Peterson, D.H., Eklund, J.J. 2014. Seed germination of calendula in response to temperature. Industrial Crops and Products. 52:199-204.

Interpretive Summary: Calendula officinalis or pot marigold has agricultural use an oilseed crop. The oil from its seed contains calendic acid, which can be used as a fast drying oil in paints and varnishes as a substitute for tung and linseed oils. Calendula is adapted to temperate climates similar to that in the northern U.S. and may be a promising rotational crop in corn/soybean systems. However, field studies in western Minnesota indicated that stand establishment was susceptible to high soil temperatures immediately after planting in spring. Consequently, understanding the temperature conditions that govern germination of calendula is necessary to incorporate the crop into crop rotations of the Upper Midwest. Temperature experiments were carried out to evaluate the germination conditions the seed requires. It was found that calendula seed should be sown in the field only if forecasted soil conditions are expected to be below 30°C during seed germination. This information is useful for growers, crop advisors, extension educators, and specialty crop company personnel, and it will support the potential incorporation of calendula into agricultural systems of Minnesota and other Upper Midwest states.

Technical Abstract: Calendula (Calendula officinalis L.) has been used historically for herbal medicinal purposes and as an ornamental plant. With the discovery that calendula seeds contain high concentrations of calendic acid (C18:3) in the 1980s it began to be investigated as an oilseed crop for use in paint, coating, and cosmetic industries as a substitute for tung and linseed oils. Calendula is adapted to temperate climates and may be a promising rotational crop in corn/soybean systems. However, field studies in western Minnesota indicated that stand establishment was susceptible to high soil temperatures immediately after planting in spring. Consequently, understanding the temperature conditions that govern germination of calendula is necessary to incorporate the crop into crop rotations of the Upper Midwest, U.S. Temperature gradient bar and heat-shock experiments were used to characterize calendula (cv. ‘Carola’) sensitivity before and during germination. Seed germinated between 2 and 32°C with the optimum germination temperature at 16-17°C. Heat shock temperatures (35-40°C) of less than 50 h duration reduced germination (at 16°C) below 50%. At 45°C, 100% seed lethality was induced within 24 h of heat treatment. Accordingly, calendula seed should be sown in the field only if forecasted soil conditions are expected to be below 30°C during seed germination.

Last Modified: 8/19/2014
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