Sparse‐Flowering Orchardgrass Represents an Improvement in Forage Quality During Reproductive Growth

Abstract

Orchardgrass (Dactylis glomerata L.) is a major component of many pastures in temperate North America. Early and profuse flowering in pastures is problematic, because livestock refuse to consume flowering stems, prompting many graziers to simply avoid using this species. The objective of this research was to determine the impact of reduced flowering on the quality of harvested forage under two harvest managements of orchardgrass. Six cultivars, three normal cultivars and three sparse‐flowering cultivars (mean panicle density of 141 vs. 61 panicles m⁻2, respectively), were evaluated in field experiments at 21 locations in North America under a 3‐cut harvest management. These cultivars were also evaluated at seven locations under a 5‐cut harvest management. Sparse‐flowering cultivars averaged 9% greater crude protein (CP), 3% lower neutral detergent fiber (NDF), 2% greater NDF digestibility, and 2% greater in vitro dry matter digestibility (IVDMD) than normal cultivars. For the two digestibility measures, differential panicle density between the cultivar groups explained a significant portion of variability, indicating that the increase in forage quality was proportional to the decrease in panicle density below a threshold of about 50 panicles m⁻2. Lastly, differences in regrowth forage quality between cultivar groups were smaller, less consistent, and of lesser statistical significance than for first harvest. While selection for sparse flowering in orchardgrass resulted in significant cause‐and‐effect increases in first‐harvest forage quality, these effects were too small to offset the reduced forage yield associated with the sparse‐flowering trait.

Flowering traits in tetraploid Brachiaria ruziziensis breeding

“…These results differ from those obtained by Casler et al (2014), in which sparse flowering cultivars presented 9% more crude protein and 3% less NDF in orchardgrass, but they corroborate with previous studies in which there was no evidence of the effect of flowering on the forage quality in the same species (Berg et al 1981). …”

Unravelling the inheritance, QST and reproductive phenology attributes of the tetraploid tropical grass Brachiaria ruziziensis (Germain et Evrard)

“…The analysis of interrelationships between the characteristics showed a strong negative genetic correlation ( r a = −0.57) between the number of panicles and NDF in B. ruziziensis , which is consistent with the results of Casler et al. () in orchardgrass. The filled‐seed yield presented a high magnitude of genetic correlations ( r a > 0.29) with NDF, total seed yield, and biomass production associated characteristics (GMY, DM yield and regrowth) in B. ruziziensis tetraploids.…”

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, 2001). More recent public orchardgrass germplasm improvement work in the United States focused on the development of nonflowering populations (Casler et al, 2013, 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).…”