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Milk Thistle (Silybum marianum) Seed Germination

Published online by Cambridge University Press:  12 June 2017

J. A. Young
Affiliation:
Sci. and Ed. Admin., U.S. Dep. of Agric., Renewable Resources Center, Univ. of Nevada, Reno, NV 89512
R. A. Evans
Affiliation:
Sci. and Ed. Admin., U.S. Dep. of Agric., Renewable Resources Center, Univ. of Nevada, Reno, NV 89512
R. B. Hawkes
Affiliation:
Sci. and Ed. Admin., U.S. Dep. of Agric., Biological Control of Weeds, Albany, CA 94706

Abstract

The germination of seeds (achenes) of milk thistle [Silybum marianum (L.) Gaertn.] was investigated. One month after harvest, milk thistle seeds had afterripening requirements related to germination temperature that limited germination to 10 to 20 C temperatures. The time required to satisfy afterripening requirements was dependent on germination temperature. Generally the higher the incubation temperature during germination, the longer the afterripening requirement (up to a maximum of 5 months). Once afterripening requirements were satisfied, milk thistle seeds germinated over a temperature range of from 0 to 30 C. Optimum germination occurred with 2 to 15 C 16-h cold periods alternating with 10 to 30 C 8-h warm periods. Emergence of milk thistle seedlings decreased with increased burial depth, but substantial emergence occurred from 8 cm. Germination on the surface of the soil or litter was greatly reduced compared to that with slight soil or litter coverage. Potassium nitrate (KNO3) added to the germination substrate at 1.0 mM enhanced the germination of milk thistle seeds at 2 and 5 C incubation temperatures.

Type
Research Article
Copyright
Copyright © 1978 by the Weed Science Society of America 

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References

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