Summer-Dormant Cool-Season Perennial Grasses | Texas A & M AgriLife Research & amp; Extension Center

A New Source of Winter-Active and Persistent Forages for Semiarid Environments of the Great Plains

Plots (center of the picture) with traditional, summer-active varieties of tall fescue (Lolium arundinaceum) after the summer drought of 2001 in Vernon, TX

For at least three decades, agronomists and plant breeders have been attempting to introduce improved cool-season perennial grasses to semiarid environments of the southern Great Plains to complement forage availability from dual-use wheat (Triticum aestivum L) pastures during the fall-winter-spring -March) grazing season and from warm-season grass pastures and native rangelands in the spring (March-May) grazing season. The introduction of traditionally recommended, improved cool-season perennial grasses has not been successful because of: 1) very limited forage production during winter grazing season, and 2) poor persistence due to inadaptability to severe water deficits accompanied by extreme heat in summer. / p>

Global climate change has an effect on the climate of the southern Great Plains. Within the last 20 years, mean annual temperature has been increasing, while annual precipitation has been decreasing (www.noaa.com). Although one may argue this may be a part of the natural climate cycle, the fact is that such changes will have an impact on agricultural crops and practices in affected regions of the world.

In environments resembling Mediterranean climate with prolonged and severe summer drought, summer-dormant cool-season perennial grasses have been more persistent than summer-active types. They are very similar to drought resistance, which is similar to that of summer-active types of drought tolerance.

Summer-dormant cool-season perennial grasses are not productive during summer therefore, they are not suitable for improved, intensive grasslands in the temperate zones of the United States. This may explain the slower progress of developing summer-dormant cultivars in the USA when compared to other countries. Our 8-year research data indicate that summer-dormant cultivars are perfectly adapted to the transitional semi-arid steppe and warm semi-arid steppe zones of the southern Great Plains, most likely because of the climate here (relatively mild winters and severe summer droughts) is similar to that of their origin.

Determine mechanisms of summer dormancy in cool-season perennial grasses Introduce summer-dormant cool-season perennial grasses to grazing systems of the southern Great Plains 2000-2008

Evaluation of forage productivity and persistence of the MaxQ summer-dormant tall fescue Arrow

2002 - 2004

Evaluation of productivity and persistence of tall fescue, orchardgrass, perennial ryegrass, and hardinggrass as a function of summer dormancy

2004 - 2007

Mechanisms of summer dormancy i Breeding of summer-dormant cool-season grasses - A cooperative project with Dr. Jaime Kigel, The Hebrew University of Jerusalem, Israel.

More news: 30 Ideas to make your pots magical

2005 - present

for southern Great Plains

2008

2009

Malinowski, DP, Kigel, J., and WE Pinchak. 2009. Water deficit, heat tolerance, and persistence of summer-dormant grasses in the U.S. Southern Plains. Crop Sci. 49: 2363-2370. Malinowski, D.P., Belesky, D.P., Kramp, B.A., Ruckle, J., Kigel, J., and W.E. Pinchak. 2008. A method to differentiate summer-dormant from summer-active tall fescue and orchardgrass accessions at germination stage. Australian J. Agric.

Texas-Israel Exchange Fund

Grasslands Innovation Ltd. (New Zealand)

  • Adam Floyd