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United States Department of Agriculture

Agricultural Research Service

Research Project: Develop Improved Plant Genetic Resources to Enhance Pasture and Rangeland Productivity in the Semiarid Regions of the Western U.S.

Location: Forage and Range Research

Title: Genetic diversity and variation in North American orchardgrass (Dactylis glomerata L.) cultivars

Authors
item Xie, Wengang -
item Bushman, Shaun
item Ma, Yingmei -
item West, Mark
item Robins, Joseph
item Michaels, Lisa
item Jensen, Kevin
item Zhang, Xinquan -
item Casler, Michael
item Stratton, Samuel -

Submitted to: Grassland Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: May 9, 2014
Publication Date: N/A

Interpretive Summary: Orchardgrass (Dactylis glomerata L.) is a high quality forage grass naturalized to temperate climates. Used extensively in hay and grazing agriculture, hundreds of orchardgrass cultivars have been released over the past 50 years. However, progress in yield and other agronomic characteristics in orchardgrass cultivars has occurred slowly and often inconsistently. One cause of the slow progress could be a lack of genetic diversity among orchardgrass cultivars, or an over-abundance of diversity within cultivars. With an emphasis on North American cultivars, this study assessed the genetic diversity within and among 52 orchardgrass cultivars, breeding lines, and accessions. Genetic similarity within cultivars ranged from 52% to 71%, similar to values from wild-land, unselected accessions. Populations from Wisconsin and Missouri breeding efforts that resulted from two cycles of genotypic recurrent selection were included as checks. Neither group of selection populations exhibited more within-population similarity compared to the wild-land accessions and cultivars. Genetic differentiation was detected only for the selection populations and several cultivars and breeding lines that had a tendency to originate from eastern Asian germplasm and have late flowering times. These results indicated an abundance of genetic variation within the orchardgrass cultivars, but a paucity of genetic differentiation among cultivars.

Technical Abstract: Orchardgrass (Dactylis glomerata L.) is a high quality forage grass naturalized to temperate climates. Used extensively in hay and grazing agriculture, hundreds of orchardgrass cultivars have been released over the past 50 years. However, progress in yield and other agronomic characteristics in orchardgrass cultivars has occurred slowly and often inconsistently. One cause of the slow progress could be a lack of genetic diversity among orchardgrass cultivars, or an over-abundance of diversity within cultivars. With an emphasis on North American cultivars, this study assessed the genetic diversity within and among 52 orchardgrass cultivars, breeding lines, and accessions. Genetic similarity within cultivars ranged from 52% to 71%, similar to values from wild-land, unselected accessions. Populations from Wisconsin and Missouri breeding efforts that resulted from two cycles of genotypic recurrent selection were included as checks. Neither group of selection populations exhibited more within-population similarity compared to the wild-land accessions and cultivars. Genetic differentiation was detected only for the selection populations and several cultivars and breeding lines that had a tendency to originate from eastern Asian germplasm and have late flowering times. These results indicated an abundance of genetic variation within the orchardgrass cultivars, but a paucity of genetic differentiation among cultivars.

Last Modified: 10/20/2014
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