# New Detection Method for Fungal Infection in Silver Fir Seeds
## 6 Conclusions  
Foresters have to deal with the problem that many forest trees, such as firs and pines, produce seeds irregularly with larger seed set every 3-4 years, and for beeches and oaks, every 4-8 years. This makes it necessary to collect large quantities of seeds in bountiful \"seed years\" and maintain them during storage. Seeds must be maintained with some moisture to maintain high viability, but this allows for a risk of fungal infection with the moisture present. Therefore, nursery workers need to be able to quickly monitor both the storage process and the health status of the seeds on a large scale to decide whether the seeds are suitable for sowing and nursery production before the start of the growing season. The objective of this study was to find a quick and inexpensive method to assess the suitability of seed lots for nursery use without laborious methods of seed germination. The working hypothesis was that an electronic nose would detect the odor of fungi and/or decaying organic matter and thus help the seed manager decide whether the seed lot was suitable for sowing in plots or should be discarded. The experiment was conducted _in vitro_ on uninfected and naturally infected _Abies alba_ silver fir seeds. We found that the commercial, general purpose electronic nose device PEN3 was able to partially discriminate between uninfected and spoiled seeds.  
The main conclusions from the presented research are as follows.  
1. At the time of measurements, fungi of the genera _Xylaria_, _Aspergillus_, and _Trichoderma_ were found on the damaged seeds.
2. Electronic nose measurement data analyzed by the machine learning algorithms can be used as a tool for evaluation of the status of silver fir seeds stockage.
3. Gas chromatography-mass spectrometry measurements can give valuable information concerning the chemical composition of the volatile organic components emitted by the spoiled seeds of silver fir.
4. \(\alpha\)-terpined seems to be the best candidate as a chemical marker of the health status of stored silver fir seeds and its significantly higher concentration may be an indication of fungal spoilage.
5. Construction of dedicated electronic noses with gas sensors targeted to specific chemical components present in volatiles emitted by fungi would be helpful to improve the performance of spoilage detection protocols.  
Conceptualization, T.O., P.B. and M.F.; methodology, T.O., M.T. and M.F.; software, P.B.; validation, P.B., R.T., M.F. and A.M.; formal analysis, M.S. and M.F.; investigation, M.F., T.M. and M.S.; resources, M.S. and A.M.; data curation, R.T. and M.T.; writing--original draft preparation, P.B., T.M., A.M. and M.S.; writing--review and editing, T.O., A.M. and T.H.; visualization, R.T., A.M. and P.B.; supervision, T.O., P.B. and M.T.; project administration, A.M.; funding acquisition, P.B. and M.S. All authors have read and agreed to the published version of the manuscript.  
This work was partially supported by the National Centre for Research and Development by the grant agreement BIOSTRATEG3/347105/9/NCBR/2017.  
Not applicable.  
Data Availability Statement: The data presented in this study are available from the corresponding author.  
Conflicts of Interest: The authors declare no conflict of interest.