Submitted to: Crop Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: April 20, 2012
Publication Date: September 1, 2012
Citation: Robins, J.G., Bushman, B.S., Jensen, K.B., Blaser, G. 2012. Genetic variation for morphology and maturity among the half-sib progeny of nine orchardgrass germplasm populations. Crop Sci. 52:2276-2282. doi: 10.2135/cropsci2012.02.01.20. Interpretive Summary: To broaden the base of available germplasm resources for orchardgrass breeding, we developed 162 families from nine orchardgrass populations. We then evaluated the families for maturity and morphology during 2008 at Rexburg, ID, and Logan, UT, field sites. We concluded that variation among genetic components for maturity and six of the eight morphological traits existed within these populations. From this genetic variation, orchardgrass breeders should be able to specifically target these orchardgrass populations in breeding programs for early, intermediate, and late maturity. We also found that the parental population 9 from the Xinjiang province of China was genetically distinct and possessed late maturity and short stature. The traits of this population make it an option for the development of later maturing orchardgrass for use in mixture with legumes or for grazing.
Technical Abstract: Orchardgrass (Dactylis glomerata L.) has traditionally been used throughout temperate regions of the world for grazing and harvested forage production. However, orchardgrass production is declining in many regions in favor of perennial ryegrass (Lolium perenne L.) or tall fescue (Festuca arundinacea Schreb.). The utilization of new sources of orchardgrass germplasm into early, intermediate, and late maturing breeding programs would be a source of novel genetic variation to improve orchardgrass deficiencies. The objective of this study was to characterize half-sib progeny developed from the random mating of genotypes from six orchardgrass germplasms and three cultivars. One hundred sixty-two half-sib families were evaluated during 2008 for maturity and morphology at locations in Idaho and Utah. Genetic variation among the half-sib families differed from zero for seven of the nine traits evaluated. Broad-sense heritability estimates for these seven traits ranged from 0.26 (flag leaf width) to 0.74 (maturity). Based on the traits evaluated and genetic similarity as measured by simple sequence repeat markers, parental populations and half-sib progeny were identified that could be used in orchardgrass breeding for the different maturity classes. In particular, the UTDG101 population that originated from collections in northwest China was the most genetically distinct of the parental populations based on SSR markers and also possessed late maturity and short stature. This population could be readily used for the development of later maturing orchardgrass for mixtures with legumes under grazing or hay production.