Turf Line News

September 2012

Issue link: http://read.dmtmag.com/i/82830

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Page 37 of 47

TURF RESEARCH BY JASON PICK, BASC., ODH AND MANAGEMENT DIHAPLOID POAS EVOLUTION, ADAPTATION Perhaps the most appropriate quote which applies in the context of poa annua management programs, is a statement by Charles Darwin ; It is not always the strongest that survives, nor the fittest, but the species that is most adaptable to change. The objective of this article is to provide an understanding of the evolution and adaptation of poa annua, as programs used to manage or eradicate demand a vocabulary of genetics, selection forces, and polyploidy. The invasion of annual bluegrass into bentgrass greens has kept turf managers modifying their management practices for more than 100 years and continues to be a challenge. It persists in as diverse of climates and management regimes as those superintendents who grow them; an ongoing dilemma which suggests its genetic diversity is a result of continuous adaptation to the management philosophies of our sports turf managers and superintendents. It is poa's adaptability to change, that has made it so competitive and opportunistic. Recent DNA mapping confirmed poa's parents poa supina and poa infirma, were a uniquely diverse combination. Poa Infirma (early meadow grass), from the Mediterranean regions of southern Europe, and poa supina from the mountainous regions of central Europe. Poa infirma, has a bunch type growth habit (similar to early stage poa encroachment into bent greens), with no use as a sports turf due to an IMAGE COURTESY PENN STATE UNIVERSITY intolerance to mowing. It is a true annual, typically dying at the 8-10 week stage. In contrast, Poa supina is a true perennial, and is extensively used in athletic fields and can manage regular mowing. Annual bluegrass's evolution has transitioned from winter annual called rough-type to the perennial referred to as greens-type. However, these two types are not exclusive; they each exist on our putting greens, representing unique attributes of both parents through the various stages of its evolution. As a true winter annual, the rough- type dies in the summer and germinates its progeny in the fall. This annual characteristic utilizes most of its energy to produce seed. The purpose is to ensure that where death occurs, the seed bank remains full and can quickly re-establish in those bare areas. The winter annual is also subsequently favored by surface disruption, opportunistically waiting for surface injury, a less densely vegetated area to invade. Still easier to kill, the rough- Continued On Next Page 38 WESTERN CANADA TURFGRASS ASSOCIATION

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