Photothermal controls of vegetative dormancy in Poa secunda

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Chen, Allen A.
Fei, Shui‐zhang
Moore, Kenneth J.
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© 2022 The Authors
Lenssen, Andrew
Professor Emeritus
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The Department of Horticulture was originally concerned with landscaping, garden management and marketing, and fruit production and marketing. Today, it focuses on fruit and vegetable production; landscape design and installation; and golf-course design and management.
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The Department of Agronomy seeks to teach the study of the farm-field, its crops, and its science and management. It originally consisted of three sub-departments to do this: Soils, Farm-Crops, and Agricultural Engineering (which became its own department in 1907). Today, the department teaches crop sciences and breeding, soil sciences, meteorology, agroecology, and biotechnology.

The Department of Agronomy was formed in 1902. From 1917 to 1935 it was known as the Department of Farm Crops and Soils.

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  • Department of Farm Crops and Soils (1917–1935)

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Iowa Nutrient Research Center
The Iowa Nutrient Research Center was established to pursue science-based approaches to evaluating the performance of current and emerging nutrient management practices and providing recommendations on practice implementation and development. Publications in this digital repository are products of INRC-funded research. The INRC is headquartered at Iowa State University and operates in collaboration with the University of Iowa and the University of Northern Iowa. Additional project information is available at:
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Background: Summer vegetative dormancy is a desirable trait in cool‐season grasses when they are interplanted with annual crops. Sandberg bluegrass (Poa secunda J. Presl.) shows summer dormancy, but the environmental cues that control dormancy remain unknown. Methods: A controlled environment study using temperature and day length combinations of 32.2°C/15 h, 26.6°C/14 h, 21.1°C/13 h, and 15.5°C/12 h was conducted with P. secunda accessions PI232347, PI639272, and PI232348, and ‘Audubon’ red fescue as a nondormant control to determine the optimum treatment for dormancy induction. A second study using treatments of 26.6°C/14 h, 21.1°C/13 h, and 15.5°C/12 h was conducted to determine the thresholds for dormancy release. A third study used a factorial experiment with two temperatures (32.2°C and 15.5°C) and two day lengths (15 and 12 h) to differentiate between temperature and day length effects on dormancy induction. Results: Of the four temperature and day length combinations, all except for 15.5°C/12 h resulted in dormancy by the end of 6 weeks, with 32.2°C/15 h inducing dormancy in only 17 days. Of the three treatments for dormancy release, 15.5°C/12 h broke dormancy the fastest in all accessions and released the most number of plants from dormancy. Considerable variation existed between accessions for the speed of dormancy release in the 21.1°C/13 h and 26.6°C/14 h treatments. The third study showed that temperature is the primary inducer for summer dormancy, while longer day length may promote dormancy under inductive temperatures. Conclusions: This study identified the optimum photothermal for induction and release of summer dormancy in P. secunda, which will help future studies in elucidating the mechanism of summer dormancy.
This article is published as Chen, Allen A., Shui‐zhang Fei, Andrew W. Lenssen, and Kenneth J. Moore. "Photothermal controls of vegetative dormancy in Poa secunda." Grassland Research 1 (2022): 43-52. doi:10.1002/glr2.12008. Posted with permission. This is an open access article under the terms of the Creative Commons Attribution‐NonCommercial License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited and is not used for commercial purposes.