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resource-scarce environments, therefore warranting efficient weed control (Wagner et al. 2004; Radosevich et al. 2007; Galatowitsch 2012, Türedi et al. 2018). Chemical weed control is an effective tool for eliminating unwanted vegetation and enhancing tree establishment and growth in forestry situations (Eºen and Yıldız 2000; Wagner et al. 2004; Eºen et al. 2005, 2006; Radosevich et al. 2007). In this sense, rapid herbicide seed screening tests can significantly help to quickly devise cost-effective, and crop-safe weed control prescriptions (Zedaker and Seiler 1988; Bunn et al. 1995; Blair et al. 2006; Stanley et al. 2014; Dağlar et al. 2016; Bakan et al. 2018; Türedi et al. 2018; Bakan 2019).
The sensitivity of plant seeds to herbicides varies depending on the herbicide, species, and application rate (Blair et al. 2006; Willoughby et al. 2006; Stanley et al. 2014; Bakan et al. 2018; Türedi et al. 2018; Bakan 2019). Black pine, maritime pine, Scots pine, and TRP exhibited similar responses to clopyralid in terms of mean cumulative seed germination and speed of germination. Clopyralid is reported to be comparatively safe in various pine species at relatively low rates. It was not phytotoxic to young seedlings of longleaf, loblolly, and slash pine at rates of 0.2-0.8 kg a.e. ha-1 (South 2000). Moreover, foliar-applied clopyralid effectively controlled Scotch broom (Cytisus scoparius L.) populations in young radiata pine (Pinus radiata D.Don) plantations at a slightly higher rate (i.e., 1.125 kg a.e. ha-1) without significant phytotoxicity to the pine seedlings one and two years after planting (Watt and Rolando 2014; Rolando et al. 2017). Additionally, clopyralid at low rates was found to be non-phytotoxic to several Mediterranean pines including black pine, Scots pine, maritime pine, and TRP in both the preliminary trial of the present study (Bakan et al. 2018; Bakan 2019) and the present study (Table 1), confirming the results of earlier studies on clopyralid. This herbicide was also found to be non-phytotoxic to Scots pine at low rates in another study where clopyralid was foliar-applied to young pine seedlings at rates of 0.14-0.56 kg a.i. ha-1 (Vea and Palmer 2009). However, this systematic herbicide became increasingly phytotoxic at rates of ≥2.0% for the pine species used in the present study (Table 1). As with the mean cumulative seed germination, clopyralid similarly reduced the germination speed for the pine species. This was particularly apparent after rates higher than 3% (Fig. 1). Consequently, clopyralid at low rates can help the practitioner eliminate critical weed competition on regeneration or propagation sites for these important pine species without significant crop damage, although it can be critically damaging to pine species at higher rates. Using high rates of clopyralid may further hurt seedling survival by decreasing the speed of seed germination because accelerated germination enables newly emerged seedlings to reach site resources earlier than other seedlings having slower germination speeds (Swanton 2003; Radosevich et al. 2007; Türedi et al. 2018).
CONCLUSION
ZAKLJUÈAK
Black pine, maritime pine, Scots pine, and TRP exhibited similar responses to clopyralid in mean cumulative seed germination and speed of germination. Clopyralid was not phytotoxic to the pine species at low rates (i.e., <2%, v:v); however, pine sensitivity to the herbicide significantly increased with increasing rates, especially for rates higher than 3%. This herbicide can be used at low rates for degraded areas and nursery sites in which sowing is used as the main regeneration or restoration method. Field studies are recommended for confirmation of the obtained results.
ACKNOWLEDGMENTS
PRIZNANJA I ZAHVALE
We thank the General Directorate of Forestry for supplying the seeds used for the present experiment. This experiment was carried out for the MSc thesis of Oğuzhan Bakan from the Duzce University Graduate School.
REFERENCES
POPIS LITERATURE
Bakan, O., D. Eºen, 2018: Karaçam, sahilçamı, kızılçam ve sarıçam tohumlarının çimlendirilmesinde mantar enfeksiyonu ile mücadele (Control of fungal infection during the seed germınation of Anatolian black, maritime, Turkish red, Scots pine), In: Full Text Book of INES 2018 (International Academic Research Congress), 1015.–1023., Alanya.
Bakan O, D. Eºen, B. Çetin, 2018: Hızlı tohum tarama testiyle bazı çam türlerinin clopyralid herbisitine hassasiyeti (Clopyralid sensitity of several pine species with rapid seed screening test), In: Full Text Book of INES 2018 (International Academic Research Congress), 833.–839., Alanya.
Bakan, O., 2019: Clopyralid herbisitinin Anadolu karaçamı (Pinus nigra J.F. Arnold), sarıçam (Pinus sylvestris L.), sahilçamı (Pinus pinaster Aiton) ve kızılçam (Pinus brutia Ten.) tohum çimlenmesine fitotoksik etkisi (The phytotoxic effects of clopyralid herbicide on seed germination of Austrian pine (Pinus nigra J.F. Arnold), Scots pine (Pinus sylvestris L.), maritime pine (Pinus pinaster Aiton) and Turkish red pine (Pinus brutia Ten.), Master’s Thesis, Graduate School of Düzce Üniversity, Düzce, pp. 65.
Blair, M. P., S. M. Zedaker, J. R. Seiler, P. L. Hipkins, P. L. Burch, 2006: Evaluation of rapid screening techniques for woody plant herbicide development, Weed Technology, (20) 971.–979.
Boydak, M., S. Çalıºkan, 2014: Ağaçlandırma, Ogem-Vakfı (in Turkish), Ankara, 712 pp.
Bunn, B. H., S. M., Zedaker, J. R., Seiler, 1995: Presoaking improves forest tree seed screening, In: Proceedings of the Southern Weed Science Society, 129.–130., Memphis
Cap, M. C., D. Eºen 2018: Effects of application date and rate of foliar-applied glyphosate on young pine seedlings in Turkey, Journal of Forestry Research, 29(3) 583.–591.