Kehler, M.R.

Schellenberg, M.P.

English

eCommons@USASK

Comparative germination of 4 western wheat grass (Agropyron smithii) cultivars under constant and alternating temperatures

University of Saskatchewan Research Archive

 Comparative Germination of 4 Western Wheat Grass (Agropyron smithii) Cultivars under Constant and Alternating Temperatures  Melissa R. Kehler and Michael P. Schellenberg    Semiarid Prairie Agricultural Research Centre (SPARC), Agriculture and Agri-Food Canada, Airport Road, Swift Current, Saskatchewan S9H 3X2 (email: mike.schellenberg@agr.gc.ca)  Key Words: seed germination, thermal gradient plate, western wheat grass  Objective  The objective of this project was to investigate seed germination requirements of 4 cultivars of western wheat grass (Agropyron smithii) under constant and alternating temperatures, similar to those temperatures found in a prairie environment. Results of this research will provide a better understanding of the requirements for successful species regeneration on the prairies.  Introduction  Future climate change will affect the germination response of native plant species. A number of native species have a large distribution range and thus may have differing germination. Temperature is an important variable affecting seed germination. To further understand the germination requirements of native prairie seed, SPARC utilizes the Thermal Gradient Plate (TGP), which features 96 cells with individual cell temperature control. Each cell is monitored with an accuracy of ±0.2°C. The TGP allows for simulation of prairie temperatures, as well as climate change.   Materials and Methods  Four WWG cultivars were selected for testing: Arriba (A), Barton (B), Recovery (R), and WR Poole (WRP). A full factorial randomized complete block statistical design with four replicates was utilized into the TGP. Germination tests were conducted with designated temperature treatments of 1) constant 20°C, 2) 10°C day/5°C night, 3) 15°C day/10°C night, 4) 20°C day/15°C night and 5) 25°C day/20°C night. Temperatures were monitored using the TGP management computer readings and a thermocouple. Fifty scarified seeds were placed in a petri dish lined with two pieces of filter paper (Whatman 597), moistened with distilled water, but with no pooling of water. A single piece of filter paper was placed on top of the seeds. Each plate was placed in its own individual cell in the TGP, with the assigned temperature treatment. The test ran for 30 days in darkness; germination counts were performed daily, recorded and germinated seeds removed. A seed showing a radicle of greater than 2 mm was considered to have germinated.         Results and Discussion  WWG cultivars showed a better germination response to the oscillating temperature than to the constant temperature of 20°C (Table 1). Overall, the best temperature for percent germination was 15°C day/10°C night but a significant difference between the cultivars was noted (Table 2). Arriba and WR Poole showed good percent germination at 15°C day/10°C night. Barton and Recovery showed good germination at the higher temperature treatments, indicating that they may be better suited for warmer climatic conditions.    Table 1: Measured parameters for germination of Western Wheat Grass cultivars: Arriba (A), Barton (B) Recovery (R) and WR Poole (WRP) germinated at a constant and alternating day/night temperatures. Means followed by different letters are significantly different (P<0.05). Factor % Germination Days to 1st Germination Days to Maximum Germination Day of Highest Germination Cultivar        (A) 36.0a 7.6b 8.7b 9.7b    (B) 26.0b 8.0b 10.0b 11.0b    (R) (WRP) 9.6c 7.6c 6.6b 13.5a 8.5b 16.6a 9.4b 17.6a Prob>F <.0001 0.0006 0.0002 0.0002 Temperature      20⁰C 12.5c 6.5b 6.8b 7.8b 10⁰C/5°C 16.0bc 14.3a 16.2a 17.0a 15⁰C/10⁰C 20°C/15°C 25°C/20°C 27.6a 23.3ab 19.6abc 7.6b 9.0ab 7.3b 10.4ab 11.6ab 9.7b 11.4ab 12.6ab 10.7b Prob>F <.0001 0.0009 0.0014 0.0019                            Table 2: Temperature effects (a constant and alternating day/night temperatures) on the Western Wheat Grass cultivars: Arriba (A), Barton (B), Recovery (R) and WR Poole (WRP). Means followed by different letters are significantly different (P<0.05). Cultivar % Germination Days to 1st Germination Days to Maximum Germination Day of Highest Germination (A)     Temperature      20⁰C 21.5b 5.25b 5.5b 6.5b 10⁰C/5°C 38.5ab 13a 17a 18a 15⁰C/10⁰C 20°C/15°C 25°C/20°C 51.5a 41.5ab 27b 7.5b 6.25b 5.75b 8.25ab 6.75b 6b 9.25ab 7.75b 7b Prob>F 0.0063 0.0002 0.0095 0.0095 (B)     Temperature      20⁰C 18a 5.75b 6.25b 7.25b 10⁰C/5°C 16.5a 15a 16.25a 17.25a 15⁰C/10⁰C 20°C/15°C 25°C/20°C 30a 33a 32.5a 7b 7b 5.25b 11.25ab 9.75b 6.25b 12.25ab 10.75b 7.25b Prob>F 0.0149 <.0001 0.0014 0.0014 (R)     Temperature      20⁰C 7.5ab 4.75 5.5 6.5 10⁰C/5°C 3.5b 10 12.25 12.75 15⁰C/10⁰C 20°C/15°C 25°C/20°C 12.5ab 10.5ab 14a 7.5 6 4.75 8.5 6 10.25 9.5 7 11.25 Prob>F 0.0240 0.6967 0.7477 0.8044 (WRP)     Temperature      20⁰C 3b 10 10 10.75 10⁰C/5°C 5.5b 19.25 19.25 20.25 15⁰C/10⁰C 20°C/15°C 25°C/20°C 16.5a 8ab 5b 8.25 16.25 13.25 13.5 24 16.25 14.5 25 12.25 Prob>F 0.0022 0.4562 0.2209 0.2185  Conclusions The results show that temperature strongly influences seed germination. The cultivars tested appear to respond to an alternating temperature than to a constant one. Some cultivars also showed a germination preference for higher temperatures, indicating they might do well in a warmer climate.   Acknowledgments Funding for this project was provided by the Saskatchewan Agricultural Development Fund and by AAFC. We gratefully acknowledge the assistance of I. Ruest, S. Bender and L. Fast.    (2015)   

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Comparative germination of 4 western wheat grass (Agropyron smithii) cultivars under constant and alternating temperatures

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