Sparse‐Flowering Orchardgrass is Stable Across Temperate North America

Abstract

Orchardgrass (Dactylis glomerata L.) is a major component of many pastures in temperate North America. Early and profuse flowering in pastures is problematic due to livestock refusal to consume flowering stems. The objective of this research was to determine the stability and agronomic impact of recently developed sparse‐flowering orchardgrass populations across temperate North America. Six cultivars, three sparse flowering and three normal flowering, were grown at 21 locations in temperate North America and evaluated for panicle density, heading date, and forage yield. Sparse‐flowering cultivars had 57% fewer panicles than normal‐flowering cultivars, but this effect was highly dependent on mean winter temperature, with normal‐flowering cultivars showing twice as much temperature sensitivity compared to sparse‐flowering cultivars. Forage yield of sparse‐flowering cultivars was reduced by approximately 24 to 32% for first harvest and 2 to 9% for regrowth harvests compared to normal‐flowering cultivars and this reduction in forage yield was independent of mean winter temperature. The forage yield reduction associated with sparse flowering is most likely due to a combination of physiological load (loss of stems) and opportunity cost (lack of selection pressure for yield), suggesting an opportunity to improve forage yield potential of this sparse‐flowering germplasm pool.

Flowering traits in tetraploid Brachiaria ruziziensis breeding

“…In this case, the valid association is that individuals with greater forage mass in the cut previous to the beginning of the flowering period were those which had more intense flowering for a longer period. Results observed for TDMY and NPP in B. ruziziensis differ from those obtained by Casler et al (2013) in orchardgrass (Dactylis glomerata L.), whose cultivars with sparse flowering presented 57% fewer panicles than the cultivars with concentrated flowering. They also presented forage yield 24% to 32% lower, depending on the cutting management.…”

Genetic Variation for Dry Matter Yield, Forage Quality, and Seed Traits Among the Half‐Sib Progeny of Nine Orchardgrass Germplasm Populations

“…Despite its place as one of the most important cool-season grasses in temperate agriculture, orchardgrass genetic improvement for either hay or grazing, particularly in North America, is minimal (Casler et al, 2000(Casler et al, , 2001. More recent public orchardgrass germplasm improvement work in the United States focused on the development of nonflowering populations (Casler et al, 2013(Casler et al, , 2014, with little documentation of other objectives. While a number of commercial cultivars from private programs are available in North America, much of this is based on the recycling of older cultivars rather than the incorporation of novel germplasm (Xie et al, 2014a).…”

“…However, each of these studies is more than 20 years old, and the majority of the sponsoring breeding programs no longer exist. The focus of more recent germplasm evaluation was Mediterranean, or winter active, accessions with little potential for most North American locations (Pecetti et al, 2009; Shaimi et al, 2009), efforts for Asian production in Japan and China (Sanada et al, 2007; Yan et al, 2013), and nonflowering orchardgrass (Casler et al, 2013; 2014). Renewed efforts in North America focus on germplasm evaluation for irrigated conditions of the Upper West and Intermountain regions (Bushman et al, 2012; Robins et al, 2012a; 2012b).…”

Lignin and Etherified Ferulates Affect Digestibility and Structural Composition of Three Temperate Perennial Grasses

“…Furthermore, genetic studies have revealed that a considerable portion of the relationship between forage NDF concentration and forage yield is due to pleiotropic effects of genes acting on both traits (i.e., causal relationships between forage NDF concentration and forage yield) (Casler, 2005, 2013). In orchardgrass, this relationship was generated specifically as a result of selection for a reduced amount of stem tissue, reducing forage yield by 30% (Casler et al, 2013) and decreasing forage NDF concentration by 3% (Casler et al, 2014). The consistent and repeatable reduction in leaf sheath, stem, and panicle tissues to selection for reduced concentration of etherified ferulates strongly suggests a concomitant reduction in forage yield is to be expected.…”