The Effect of Gibberellic Acid, After-Ripening and Eliminating Glumelle on Germination of Japanese Brome (Bromus japonicus Thunb.) Seeds

Document Type : Research Article


1 Ferdowsi University of Mashhad

2 University of Zabol

3 Iranian Research Institute of Plant Protection


Introduction: Japanese brome (Bromus japonicus Thunb.) is one of the most important annual narrow leaf weeds in wheat fields of Sistan and Baluchistan province. About 2 to 22 percent of yield loss depends on density and wheat cultivar. Fresh seeds of B. japonicus are classified on non-dormant or non-deep physiological dormant seeds. Treating by gibberellic acid is highly effective in both the embryo growth and seed germination processes in this type of dormancy. One of the important goals of germination and emergence studies in weed science is prediction of the dormancy longevity and germination time in field conditions. Therefore, the aim of this study was to evaluate germination properties of seeds at different times after physiological examination under the effect of gibberellic acid.
Materials and Methods: An experiment was carried out as factorial based on randomized complete block design in 2013. Experimental factors were included six levels of 1- period of after ripening (immediately after harvest, 2, 4, 6, 9 and 12 months after harvest) and 2- pre-treatment by gibberellic acid for 48 hours in four concentrates (0, 100, 200, 300 mg lit-1). The effect of these factors was evaluated for two types of Japanese brome seeds; glumelle and non-glumelle. Samples placed into the incubator and temperature was kept on 20◦C in dark condition. Germination percentage, germination rate and mean germination time were recorded in every 48 hours. Analysis of data was performed using PROC GLM procedure of SAS (Version 9.2; SAS Institute, Cary, NC, USA). A three parameter sigmoidal model was fitted to the data using PROC NLIN of SAS to find the relationship between germination percentage and gibberellic acid concentration.
Results and Discussion: The results showed that the effect of all experimental factors on germination properties was significant (P <0.01). Removal of glumelle, increasing the concentration of gibberellic acid and keeping more time after harvesting significantly increased germination percentage. The fitted model showed that the time to reach 50% of maximum germination in non-glumelle seeds was less than one month (T0> 1). In glumelle seeds, it takes about 6 months to reach 50% of its maximum (63%) in the 12th month after harvest. Germination rate increased from 1.7% per day in glumelle seeds to 15.5% per day in non- glumelle seeds. The duration of seed storage had a significant effect on its germination rate, so that at 12 months after harvest, it was approximately 15 times higher than harvest time. For the first three times after harvest; 0, 2 and 4 months after harvest, non-glumelle seeds showed a higher mean germination time than intact seeds, and vice versa, for the second three times; 6, 9 and 12 months after harvest.
Conclusion: In this study, although the effect of gibberellic acid on enhancing germination was positive and there was significant differences among the four levels of this hormone, but its effect on glumelle seeds was higher than non-glumelle seeds. In other words, by removing glumelle, the effect of seed germination is reduced by the use of gibberellic acid. This experiment showed that removing glumelle and keeping seeds of the Japanese for 2 months and more have the greatest contribution to reduce non-deep physiological dormancy of this weed.


1. Baskin J.M. and Baskin C.C. 1981. Ecology of germination and flowering in the weedy winter annual grass Bromus japonicus. Journal of Range Management, 34: 369-372.
2. Baskin, C.C., and Baskin, J.M. 2014. Seeds: ecology, biogeography, and evolution of dormancy and germination. 2nd Eds. Elsevier/Academic Press, San Diego.
3. Bahrani M.J., Ramazani M., Shekafandeh A., and Taghavi M. 2008. Seed germination of wild caper (Capparis spinose L. var parviflora) as affected by dormancy breaking treatment and salinity levels. Seed Science and Technology, 36: 779-780.
4. Balouchi H.R., and Modarres Sanavi S.M. 2006. Effect of gibberellic acid, prechiling, sulfuric acid and potassium nitrate on seed germination and dormancy of annual Medics. Pakistan Journal of Biological Science, 9: 2875-2880.
5. Basiri M. 2016. The reaction of grain yield and yield components of wheat (Triticum aestivum L.) varieties in competition with Japanese brome (Bromus japonicus Thunb.) in Sistan region. PhD Thesis. University of Zabol, Zabol, Iran. (In Persian with English abstract)
6. Bannayan M., and Najafi F. 2004. Final report study of germination in seeds of wild medicinal plants in Iran. Department of Agronomy, College of Agricultural,. Ferdowsi University of Mashhad, Mashhad, Iran. (In Persian with English abstract)
7. Chasemi Pirbalooti A., Golparvar A.R., Riahi Dehkordi M., and Navid A.R. 2006. The effect of different treatment on breaking dormancy and stimulat germination of five species of medicin and aromatic plants in Chaharmahal and Bakhtiari. Research and Development on Natural Resources, 74:185-192. (In Persian with English abstract)
8. Che J.D., Yuan Z.Q., Jin D.H., Wang Y.M., Zhang G.W., Hu X.G., Wu J.Z., and Tian Z.Y. 2010. Study report of Bromus japonicas Thunb. biological characteristics. Beijing Agric, 36: 41-43.
9. Eslami S.W., Afghani F., and Mahmoodi S. 2008. Effect of environmental factors on germination and longevity of downy brome (Bromus tectorum) seeds. Iranian Society of Seed Science, 2:47-57. (In Persian with English abstract)
10. Finch-Savage W.E., and Leubner-Metzger G. 2006. Seed dormancy and the control of germination. New phytologist, 171: 501-523.
11. Gasch C., and Bingham R. 2006. Variation in seed germination characteristics among population of Bromus tectorum in the Gunnison Basin. Bios, 77: 7-12.
12. Greipsson S. 2001. Effects of stratification and GA3 on seed germination of a sand stabilizing grass (Leymus arenarius L.) used in reclamation. Seed Science and Technology, 29: 1-10.
13. Koochaki A., and Azizi G. 2005. Effect of different treatments on seed germination dormancy in Teucrium polium. Iranian Journal of Field Crop Research, 3: 81-88. (In Persian with English abstract)
14. Koornneff M., Bentsink L., and Hilhorst H. 2002. Seed dormancy and germination. Current Opinion in Plant Biology, 5: 33-36.
15. Karl M.G., Heitschmidt R.K., and Haferkamp M.R. 1999. Vegetation biomass dynamics and patterns of sexual reproduction in a norther mixed-grass prairie. American Midland Naturalist, 141: 227-237.
16. Li Q., Tan J., Li W., Yuan G., Du L., Ma S., and Wang J. 2015. Effect of environmental factors on seed germination and emergence of Japanese Brome (Bromus japonicas). Weed Science, 63: 641-646.
17. Liu K., Baskin J.M., Baskin C.C., Bu H., Liu M., Liu W., and Du G. 2011. Effect of storage conditions on germination of seeds of 489 species from high elevation grasslands of the eastern Tibet Plateau and some implications for climate change. American Journal of Botany, 98: 12-19.
18. Littell R.C., Stroup W.W., Milliken G.A., Wolfinger R.D., and Schabenberger O. 2006. SAS for mixed models. SAS institute.
19. Macchia M.L., Angelini G., and Ceccarini L. 2001. Methods to overcome seed dormancy in Echinacea angustifolia. Scientia Horticulturae, 89: 317-324.
20. Meyer S.E., and Allen P.S. 1999. Ecological genetics of seed germination regulation in Bromus tectorum: I. Phenotypic variance among and within population. Oecologia, 19: 225-239.
21. Meyer S.E., and Allen P.S. 2009. Predicting seed dormancy loss and germination timing for Bromus tectorum in a semi-arid environment using hydrothermal time models. Seed Science Research, 19: 225-239.
22. Meyer S.E., Allen P.S., and Beckstead J. 1995. Patterns of seed after-ripening in Bromus tectorum L. Journal of Experimental Botany, 46: 1737-1744.
23. Makizadeh Tafti M., Farhoodi R., Rastifar M., and Sadat Asilan K. 2011. Seed dormancy breaking methods in Caparis spinosa. Iranian Journal of Range and Desert Research, 8:569-577. (In Persian with English abstract)
24. Naebi M., Roshandel P., and Mohammadkhani A. 2011. Study of methods in dormancy breaking and enhancing germination in Rhum ribes. Iranian Journal of Medicine and Aromatic Plants Research, 17: 212-223. (In Persian with English abstract)
25. Najafi M., Bannayan M., Tabrizi L., and Rastgoo M. 2006. Seed germination and dormancy breaking techniques for ferula gammusa and Teucrium polium. Journal of Arid Environments, 4:542-547.
26. Ranal M.A., and Santana D.G. 2006. How and why to measure the germination process? Revista Brasileira de Botanica, 29: 1-11.
27. Rhie Y.H., Lee S.Y., and Kim K.S. 2015. Seed dormancy and germination in Jeffersonia dubia (Berberidaceae) as affected by temperature and gibberellic acid. Plant Biology, 17: 327-334.
28. Sarani M. 2005. Evaluation of different wheat (Triticum aestivum L.) cultivars in competition with Japanese brome (Bromus japonicus Thunb.). MSc Thesis. Ferdowsi University of Mashhad, Mashhad, Iran. (In Persian with English abstract).
29. Tavili A., Safari B., and Saberi M. 2010.The effect of gibberellic acid and potassium nitrate on improving germination of (Salsola rigida). Journal of Range Research, 3: 272-285. (In Persian with English abstract)
30. Whisenant S.G., and Steven G. 1990. Post-fire population dynamic of Bromus japonicas American Midland Naturalist, 123: 301-308.
31. Wei M. 2010. Biological characteristics of Japanese brome observed in the wheat of Zhuangland country. Gansu Agricultural Science Technology, 8: 30-31.
32. Beckstead J., Meyer S.E., and Allen P.S. 1996. Bromus tectorum seed germination: between-population and between-year variation. Canadian Journal of Botany, 74: 875-882.
33. Salimi H., and Termeh F. 2000. A study on seed dormancy and germination in ten species of grass weeds. Rostaniha, 3:11-23.
34. Serrano C., Chueca M.C., and Garcia-Baudin J.M. 1992. A study of germination in Bromus spp. p. 217-221. In Proceedings of the 1992 Congress of the Spanish Weed Science Society.