Annual changes in temperature and light requirements for Ipomoea purpurea seed germination with after-ripening in the field following dispersal

Published Date
Crop Protection
January 2015, Vol.67:84–90, doi:10.1016/j.cropro.2014.09.021

• Author 

• Prashant Jha ^a,,
• Jason K. Norsworthy ^b
• Vipan Kumar ^a
• Nicholas Reichard ^a

• aMontana State University, Southern Agricultural Research Center, Huntley, MT 59037, USA
• bUniversity of Arkansas, Department of Crop, Soil, and Environmental Sciences, Fayetteville, AR 72704, USA

Received 14 July 2014. Revised 5 September 2014. Accepted 25 September 2014. Available online 17 October 2014. 

Highlights

• •
  Freshly matured Ipomoea purpurea seeds have physical dormancy.
• •
  Seeds exhibit temperature-mediated annual dormancy cycling.
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  Light has minimal impact on germination over the 12-month period after dispersal.
• •
  Seeds can germinate over an extended period (spring through autumn) in the field.
• •
  The research would aid in understanding I. purpurea seed bank dynamics.

Abstract

Field and laboratory experiments were conducted in SC, USA, in 2004/2005 and 2006/2007 to determine the effect of temperature, light, and spring burial on Ipomoea purpurea (L.) Roth. seed germination over a 12-month period after seed maturation in the field. The seed collections used for the temperature and light studies had physical dormancy (water-impermeable), with 10–23% and 17–46% germination, respectively, of the freshly matured viable seeds. Freshly matured seeds used for the temperature study germinated to higher percentages at 15–25 °C constant. During winter (3 months after seed maturation), seed germination was higher at 30 °C constant or 22.5/37.5 °C fluctuating. During spring (6 months after seed maturation), there was a widening of thermal range (10–40 °C constant or 2.5/17.5 to 27.5/42.5 °C fluctuating) for germination. Germination of surface-lying or buried seeds was higher at 35–40 °C constant or 22.5/37.5–27.5/42.5 °C fluctuating in late summer (9 months after maturation) and autumn (12 months after maturation). Light had minimal influence on germination of surface or buried seeds of the tested population over the 12-month after-ripening period. A temperature-mediated annual dormancy continuum of I. purpurea seed has been proposed in this research, which will contribute to the development of weed emergence models aimed at improving strategies for I. purpurea control in the field.

Keywords

After-ripening

Dormancy

Seed germination

Temperature

Light

Seed burial

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