High perennial ryegrass seeding rates reduce plant size and survival during the first year after sowing: does this have implications for pasture sward persistence?

Lee, J. M.; Thom, E. R.; Wynn, K.; Waugh, Deanne; Rossi, Laura; Chapman, D. F.

doi:10.1111/gfs.12243

Cited by 15 publications

(31 citation statements)

References 29 publications

(36 reference statements)

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“…Intensive data from the first year of this experiment have been reported previously by Lee et al. ().…”

Section: Introductionmentioning

confidence: 54%

“…This is likely a result of self‐thinning processes (Harper & White, ), which are described in greater detail for this study by Lee et al. (). The length of time that the effects on botanical composition remained differed across the sites, with differences dissipating much earlier at the Waikato site than the Northland site.…”

Section: Discussionmentioning

confidence: 78%

“…All four cultivars of one seeding rate treatment (18 kg/ha) were monitored for a fifth year at each site. Intensive data from the first year of this experiment have been reported previously by Lee et al (2017).…”

mentioning

confidence: 61%

“…Tiller density differences generally dissipated by the start of the second (Northland and Waikato) or third (Canterbury) year after sowing, at least between treatments within the range of 12-30 kg/ha. This is likely a result of self-thinning processes (Harper & White, 1970), which are described in greater detail for this study by Lee et al (2017). The length of time that the effects on botanical composition remained differed across the sites, with differences dissipating much earlier at the Waikato site than the Northland site.…”

Section: Endophyte Infection Frequencymentioning

confidence: 77%

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High perennial ryegrass seeding rates do not negatively impact pasture sward persistence

Lee

Thom

Chapman

et al. 2017

Grass and Forage Science

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Poor persistence of perennial ryegrass swards is a common problem; however, there is a lack of long‐term studies to understand the mechanisms associated with poor persistence. This study describes an experiment to test the hypothesis that high ryegrass seeding rates (>18 kg seed per ha) reduce long‐term population persistence because of smaller plant size and poorer survival during the first year after sowing. Four cultivars, representing four functional types of perennial ryegrass, were sown at five seeding rates (equivalent to 6, 12, 18, 24 and 30 kg seed per ha) with white clover in three regions of New Zealand. Swards were monitored for 5 years. No evidence was found to indicate a lack of persistence of ryegrass‐based swards sown at higher seeding rates. During the first year, swards sown at higher seeding rates had greater herbage accumulation (except at the Waikato site), greater ryegrass tiller density and greater ryegrass content. This initial impact of high seeding rates had largely dissipated by the fourth year, resulting in swards with similar annual herbage accumulation, tiller density and botanical composition. Similarly, there were relatively few differences among cultivars for these variables. Although high seeding rates did not negatively impact sward persistence, geographical location did, with strong evidence of ryegrass population decline at the Waikato site for all treatment combinations, some decline in Northland, and stable populations in Canterbury. It is possible that productive perennial ryegrass pastures can only be sustained for 4–5 years in some situations, even when the best ryegrass technology and management practices are used.

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“…Intensive data from the first year of this experiment have been reported previously by Lee et al. ().…”

Section: Introductionmentioning

confidence: 54%

Section: Discussionmentioning

confidence: 78%

mentioning

confidence: 61%

Section: Endophyte Infection Frequencymentioning

confidence: 77%

See 2 more Smart Citations

High perennial ryegrass seeding rates do not negatively impact pasture sward persistence

Lee

Thom

Chapman

et al. 2017

Grass and Forage Science

Self Cite

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show abstract

“…For HA, divergent selections were made in each selection population based on a simple additive index of HA GEBVs (models described in [20]), weighted towards growth in the Waikato environment, which is considered most challenging for ryegrass growth [32,33]:…”

Section: Selection and Polycross Isolationsmentioning

confidence: 99%

Divergent Genomic Selection for Herbage Accumulation and Days-To-Heading in Perennial Ryegrass

et al. 2020

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Increasing the rate of genetic gain for dry matter (DM) yield in perennial ryegrass (Lolium perenne L.), which is a key source of nutrition for ruminants in temperate environments, is an important goal for breeders. Genomic selection (GS) is a strategy used to improve genetic gain by using molecular marker information to predict breeding values in selection candidates. An empirical assessment of GS for herbage accumulation (HA; proxy for DM yield) and days-to-heading (DTH) was completed by using existing genomic prediction models to conduct one cycle of divergent GS in four selection populations (Pop I G1 and G3; Pop III G1 and G3), for each trait. G1 populations were the offspring of the training set and G3 populations were two generations further on from that. The HA of the High GEBV selection group (SG) progenies, averaged across all four populations, was 28% higher (p < 0.05) than Low GEBV SGs when assessed in the target environment, while it did not differ significantly in a second environment. Divergence was greater in Pop I (43%-65%) than Pop III (10%-16%) and the selection response was higher in G1 than in G3. Divergent GS for DTH also produced significant (p < 0.05) differences between High and Low GEBV SGs in G1 populations (+6.3 to 9.1 days; 31%-61%) and smaller, non-significant (p > 0.05) responses in G3. This study shows that genomic prediction models, trained from a small, composite reference set, can be used to improve traits with contrasting genetic architectures in perennial ryegrass. The results highlight the importance of target environment selection for training models, as well as the influence of relatedness between the training set and selection populations.

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Establishing phenotypic performance of grass varieties on Irish grassland farms

et al. 2017

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SUMMARYConventionally perennial ryegrass evaluations are conducted under simulated grazing studies to identify varieties with the best phenotypic performance. However, cut-plot environments differ greatly to those experienced on commercial farms as varieties are not exposed to the same stress levels in test environments. It could be argued that plot-based testing regimes provide little direction to plant breeders in the development of advanced varieties. Varietal phenotypic performance needs to be quantified in ‘commercial’ situations. The objective of the current study was to evaluate the phenotypic performance of a range of perennial ryegrass varieties under commercial farm conditions. Monocultures of 11 Irish Recommended List perennial ryegrass varieties were sown on 66 commercial farms throughout Ireland where performance was evaluated over a 3-year period from 2013 to 2015, inclusive. A linear mixed model was used to quantify variety effects on grassland phenotypic performance characteristics. No significant variety effect was estimated for total, seasonal or silage herbage production. Despite the lack of variety effects, pairwise comparisons found significant performance differences between individual varieties. Grazed herbage yield is of primary importance and was shown to be correlated strongly with total production (0.71); Grazed herbage yield differed significantly by variety, with a range of 1927 kg dry matter (DM)/ha between the highest and lowest performing varieties. Sward quality (dry matter digestibility [DMD]) and density were influenced by variety with a range of 44 g/kg DM for DMD and 0.7 ground score units between the highest and lowest performing varieties. Results of the current study show that on-farm evaluation is effective in identifying the most suitable varieties for intensive grazing regimes, and the phenotypic variance identified among varieties performance for many traits should allow for improved genetic gain in areas such as DM production, persistence and grazing efficiency.

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High perennial ryegrass seeding rates reduce plant size and survival during the first year after sowing: does this have implications for pasture sward persistence?

Cited by 15 publications

References 29 publications

High perennial ryegrass seeding rates do not negatively impact pasture sward persistence

High perennial ryegrass seeding rates do not negatively impact pasture sward persistence

Divergent Genomic Selection for Herbage Accumulation and Days-To-Heading in Perennial Ryegrass

Establishing phenotypic performance of grass varieties on Irish grassland farms

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