Genetic Variation for Morphology and Maturity Among the Half‐Sib Progeny of Nine Orchardgrass Germplasm Populations

Abstract

Orchardgrass (Dactytis giomerata L.) acreage has declined compared to perennial ryegrass (Loiium perenne L.) and tall fescue (Festuca arundinacea Schreb.). With the intent of developing new sources of orchardgrass germplasm, 162 half-sib families from six orchardgrass germplasm populations and three orchardgrass cultivars were evaluated during 2008 for maturity and plant morphology at locations in Idaho and Utah. Genetic similarity of the populations was also characterized using simple sequence repeat markers. Genetic variation between families differed from zero for seven of the nine traits evaluated, with broadsense heritability estimates ranging from 0.26 (flag leaf width) to 0.74 (maturity). For each trait that exhibited genetic variation, half-sib families were identified that possessed trait values similar to or more extreme than the values corresponding to the included commercial orchardgrass cultivars. Through principle component analysis, potential groupings of half-sib families with similar phenotypic characteristics were identified; for example, taller plants with earlier maturity. Therefore, germplasm could be targeted for development of improved orcbardgrass with maturity and morphology suitable to specific management practices, such as short stature, narrow leaves, and late maturity for mixture with legumes.

UTDG-101, a Late-Maturing Orchardgrass Germplasm with Increased Winter Hardiness and Forage Quality

“…Due to the lack of variation for location and genotype × location effects, data were pooled across the two locations (Millville, UT, and Rexburg, ID) (Robins et al, 2012b). When combined over locations (Table 4), UTDG‐101 had shorter culms (67.7 cm; P < 0.05) than orchardgrass cultivars Baridana (Barenbrug, USA), Century (FFR Cooperative), DawnXL (Forage First), Frode (DLF International), Haymate (FFR Copperative), and Icon (FFR Cooperative) but had a similar culm length to cultivars Baraula (Barenbrug, USA), Barlemus (Barenbrug, USA), Century, and Intensiv (Barenbrug, USA).…”

“…UTDG‐101 was previously described morphologically (Robins et al, 2012b) and is described only briefly here. Morphological samples were collected by clipping a culm at soil level from the second, fifth, and eighth plants in each plot.…”

“…Morphological traits included culm length (cm), culm width (mm), flag leaf height (cm), flag leaf length (cm), flag leaf width (mm), panicle height (cm), spikelet length (mm), and the number of nodes per spikelet (see Table 4). See Robins et al (2012b) for details on statistical analysis.…”

Heterosis for protein, digestibility, fiber, and water soluble carbohydrates in nine sources of orchardgrass germplasm

“…The germplasm pools derive from Asian, European, and North American sources, including three of the most common varieties grown under irrigated conditions: Latar, Paiute, and Potomac. There exists genetic variation among the nine germplasm pools for morphological and agronomic traits, including plant height, heading date, dry matter yield, nutritive value, and seed production (Robins et al 2012b;Robins et al unpublished data). Differences in simple sequence repeat markers also illustrate the genetic differences among the germplasm sources (Robins et al 2012a), although the genetic differences identified by these molecular markers provided limited heterotic predictive value for these forage quality traits.…”

Registration of USDA‐UTWH‐102 Winter‐Hardy Orchardgrass Germplasm

“…O rchardgrass ( Dactylis glomerata L.) is an important cool‐season grass for temperate forage production worldwide (Stewart and Ellison, 2010). Producers value it for nutritive value, high herbage mass potential, and excellent mixing ability with alfalfa ( Medicago sativa L.; Robins et al, 2012). One of orchardgrass's main limitations is its susceptibility to winter injury and mortality at higher elevations and northern latitudes (Sanada et al, 2007).…”