Seed germination in Silphium perfoliatum L. & Sida hermaphrodita L. and technological measures for its improvement Markus Gansberger1,2, Manfred Weinhappel1, Philipp von Gehren1,2, Andreas Ratzenböck1, Peter Liebhard2, Josef Mayr1 1
Austrian Agency for Health and Food Safety (AGES), Division for Food Security, Institute for Seed and Propagating Material, Phytosanitary Service and Apiculture, Spargelfeldstrasse 191, 1220 Vienna, Austria. 2 University of Natural Resources and Life Sciences Vienna (BOKU), Department of Crop Sciences, Division of Agronomy, Augasse 2-6, 1090 Vienna, Austria. Corresponding author: Markus Gansberger E-mail:
[email protected]
Abstract Silphium perfoliatum L. and Sida hermaphrodita L. are new alternative energy crops that are currently planted as pre-cultured seedlings. Sowing is currently not practical, as the not prepared seeds have low germinability and there is a lack of experience concerning appropriate sowing conditions. Different laboratory tests were conducted to determine factors influencing germination, to answer the question of dormancy, and to develop technological measures to achieve a high seed quality. The final aim of this basic work will be to develop a seed technology for Silphium and Sida to get a high field emergence. The factors „medium”, “light”, “temperature”, “pre-treatment” and “pre-chilling“ were examined regarding their influence on germination of Silphium perfoliatum L. The germination test method was based on observing these factors in two to four different levels, e.g. three different temperature levels, to determine the optimal level. In total, 144 combinations or methods were tested in eight replicates with 50 seeds and two different seed lots (Lot A, Lot B). The germination test procedure for Sida hermaphrodita L. was similar but with slightly different levels, and included the factors "lot”, “light”, “temperature”, “pre-treatment” and “pre-chilling". Pleated paper was utilized as medium was utilized and only four replicates with 50 seeds were used. In addition, different seed processing procedures were checked during the germination tests to get a higher seed quality for the seed lot A of Silphium perfoliatum L.. Moreover, seed pills were developed in consideration of the laboratory results of the germination tests.
The results of the germination tests of Silphium perfoliatum L. showed that fresh seeds are dormant, and stratification or pretreatment with KNO3 and GA3 have positive effects on germination. However, the factor temperature had the most significant effect, as changing temperatures with high temperature amplitudes were found to be particularly favorable. As a result of the test series, the following germination method can be derived for Silphium perfoliatum L.: medium: pleated paper / light: 12 hours light – 12 hours dark / pre-chilling: 7 days - 5°C / temperature: 20 30°C / pre-treatment: GA3. All factors, except pre-chilling, showed a significant effect on the germination of Sida hermaphrodita L.. The optimal set of factors was determined to be no treatment with the fungicide thiram, germination in the dark, changing temperatures between 20 and 30°C every 12 hours and pre-treatment with GA3. From all tested possibilities aiming to increase seed quality for Silphium perfoliatum L. the combination sieving machine and gravity separator was found to be the most advantageous. After processing seed lot A had a purity of 99.1% and a viability of 97.5%. The production of seed pills was also successful, so that mechanical sowing is feasible without much doubt.
Acknowledgements Work on Silphium perfoliatum L. and Sida hermaphrodita L. is done within the projects “Bioenergy-Silphium” and “SIDecA”. These projects are funded by the Climate and Energy Fund and conducted under the programs “new energies 2020” and “e!MISSION”. For assistance in the design of the experimental model and in the statistical analysis we would like to thank Ao.Univ.Prof. Dipl.-Ing. Dr. Karl Moder (BOKU) and Mag. Dr. Hans-Peter Stüger (AGES). Thanks also to Cimbria Heid GmbH for their support and cooperation in the development of a processing method of the harvest material to obtain high seed quality, and Kwizda Agro GmbH for their support and design of seed pills for Silphium perfoliatum L. on the basis of laboratory results.
References GANSBERGER M, MONTGOMERY LFR, LIEBHARD P, 2015: Botanical characteristics, crop management and potential of Silphium perfoliatum L. as a renewable resource for biogas production: a review. Ind. Crops Prod. 63. 362–372. doi:10.1016/j.indcrop.2014.09.047. SOKOLOV VS, GRITSAK ZI, 1972: Silphium – a valuable fodder and nectariferous
crop. World Crops 24, 299-301. STANFORD G, 1990: Silphium perfoliatum (cup-plant) as a new forage. In: Recapturing a Vanishing Heritage. 12. North American Prairie Conference, University of Northern Iowa, Cedar Falls, 33-38. TRÖLENBERG SD, KURSE M, JONITZ A, 2012: Verbesserung der Saatgutqualität bei der Durchwachsenen Silphie (Silphium perfoliatum L.), In: Nachhaltigkeitsindikatoren für die Landwirtschaft: Bestimmung und Eignung, VDLUFA-Schriftenreihe. 124. VDLUFA-Kongress, VDLUFA-Verlag, Darmstadt, 926-933. TROXLER J, DACCORD R, 1982: Silphium perfoliatum L.: An interesting fodder? Rev. Suisse D’agriculture 14, 279-281.
