• A note on the conservation characteristics of baled grass silages ensiled with different additives.

      Keles, G.; O'Kiely, Padraig; Forristal, P.D. (Teagasc, Oak Park, Carlow, Ireland, 2010)
      The effects of contrasting conventional silage additives on chemical composition, aerobic stability and deterioration, and mould development in baled silage were investigated. Herbage from a grassland sward was wilted for 24 h and treated with acid (formic or sulphuric), sugar (molasses), bacterial (Lactobacillus plantarum, L. plantarum + Serratia rubidaea + Bacillus subtilis, or L. buchneri) or sugar + bacterial (molasses + L. plantarum) additives prior to baling and wrapping. Silage made without an additive preserved well and had a low incidence of mould growth, and the effects of additives were minor or absent. It is concluded that little practical benefit was realised when conventional additives were applied to wilted, leafy, easy-to-ensile grass prior to baling and ensilage.
    • A note on the effect of elevated concentrations of greenhouse gases on spring wheat yield in Ireland

      Donnelly, A; Finnan, John; Jones, M. B.; Burke, James I. (Teagasc (Agriculture and Food Development Authority), Ireland, 2005)
      Spring wheat (Triticum aestivum L., cv. Minaret) was grown to maturity in open-top chambers under two concentrations of CO2 (ambient and 680 μmol/mol) and two concentrations of O3 (ambient and ambient +90 nmol/mol). Elevated concentrations of CO2 increased grain yield whereas yield was reduced by elevated O3. The damaging effect of elevated O3 on grain yield was reduced when the crop was grown in a combination of elevated CO2 and elevated O3. It is concluded that wheat production in Ireland is expected to benefit from rising concentrations of atmospheric CO2.
    • Novel Approaches to Optimise Early Growth in Willow Crops

      Donnelly, Isabella; McDonnell, Kevin; Finnan, John; Teagasc Walsh Fellowship Programme (MDPI, 2019-06-03)
      Willow is a fast growing, high yielding biomass crop that can help reduce reliance on fossil fuels. However, long establishment times to get to profitability and sustainable yield may deter interest in planting the crop. A number of different approaches were investigated to optimise and accelerate early growth. These approaches were water immersion, plastic application, altering stem orientation at planting, altering coppicing timings and applying growth hormone. Glasshouse and field trials were used to test the different approaches. In this work, planting material was soaked for a varying number of days and plastic was applied or not applied in field trials. In the planting orientation approach, stems were planted diagonally or vertically with half of the planting material above the ground level or horizontally below ground level. Additionally, willow crops were coppiced at different times throughout their first growing season and a growth hormone trial was also incorporated in this work. Water soaking, plastic application, coppicing during the growing season or hormone application did not improve early growth or yield. However, early growth and yield were increased by manipulating the planting orientation of willow stems. Planting orientation treatments in which part of the stem was left above the ground increased early growth and yield significantly compared to the control without requiring extra inputs at planting. The beneficial effects of coppicing can be achieved by manipulating the planting procedure so that the first year’s growth is not disregarded.
    • A Novel Multivariate Approach to Phenotyping and Association Mapping of Multi-Locus Gametophytic Self-Incompatibility Reveals S, Z, and Other Loci in a Perennial Ryegrass (Poaceae) Population

      Thorogood, Daniel; Yates, Steven; Manzanares, Chloé; Skot, Leif; Hegarty, Matthew; Blackmore, Tina; Barth, Susanne; Studer, Bruno; Biotechnology and Biological Sciences Research Council; Swiss National Science Foundation; et al. (Frontiers, 2017-08-02)
      Self-incompatibility (SI) is a mechanism that many flowering plants employ to prevent fertilisation by self- and self-like pollen ensuring heterozygosity and hybrid vigour. Although a number of single locus mechanisms have been characterised in detail, no multi-locus systems have been fully elucidated. Historically, examples of the genetic analysis of multi-locus SI, to make analysis tractable, are either made on the progeny of bi-parental crosses, where the number of alleles at each locus is restricted, or on crosses prepared in such a way that only one of the SI loci segregates. Perennial ryegrass (Lolium perenne L.) possesses a well-documented two locus (S and Z) gametophytic incompatibility system. A more universal, realistic proof of principle study was conducted in a perennial ryegrass population in which allelic and non-allelic diversity was not artificially restricted. A complex pattern of pollinations from a diallel cross was revealed which could not possibly be interpreted easily per se, even with an already established genetic model. Instead, pollination scores were distilled into principal component scores described as Compatibility Components (CC1-CC3). These were then subjected to a conventional genome-wide association analysis. CC1 associated with markers on linkage groups (LGs) 1, 2, 3, and 6, CC2 exclusively with markers in a genomic region on LG 2, and CC3 with markers on LG 1. BLAST alignment with the Brachypodium physical map revealed highly significantly associated markers with peak associations with genes adjacent and four genes away from the chromosomal locations of candidate SI genes, S- and Z-DUF247, respectively. Further significant associations were found in a Brachypodium distachyon chromosome 3 region, having shared synteny with Lolium LG 1, suggesting further SI loci linked to S or extensive micro-re-arrangement of the genome between B. distachyon and L. perenne. Significant associations with gene sequences aligning with marker sequences on Lolium LGs 3 and 6 were also identified. We therefore demonstrate the power of a novel association genetics approach to identify the genes controlling multi-locus gametophytic SI systems and to identify novel loci potentially involved in already established SI systems.
    • A Novel Multivariate Approach to Phenotyping and Association Mapping of Multi-Locus Gametophytic Self-Incompatibility Reveals S, Z, and Other Loci in a Perennial Ryegrass (Poaceae) Population

      Thorogood, Daniel; Yates, Steven; Manzanares, Chloé; Skot, Leif; Hegarty, Matthew; Blackmore, Tina; Barth, Susanne; Studer, Bruno; Biotechnology and Biological Sciences Research Council; Swiss National Science Foundation; et al. (Frontiers, 2017-08-02)
      Self-incompatibility (SI) is a mechanism that many flowering plants employ to prevent fertilisation by self- and self-like pollen ensuring heterozygosity and hybrid vigour. Although a number of single locus mechanisms have been characterised in detail, no multi-locus systems have been fully elucidated. Historically, examples of the genetic analysis of multi-locus SI, to make analysis tractable, are either made on the progeny of bi-parental crosses, where the number of alleles at each locus is restricted, or on crosses prepared in such a way that only one of the SI loci segregates. Perennial ryegrass (Lolium perenne L.) possesses a well-documented two locus (S and Z) gametophytic incompatibility system. A more universal, realistic proof of principle study was conducted in a perennial ryegrass population in which allelic and non-allelic diversity was not artificially restricted. A complex pattern of pollinations from a diallel cross was revealed which could not possibly be interpreted easily per se, even with an already established genetic model. Instead, pollination scores were distilled into principal component scores described as Compatibility Components (CC1-CC3). These were then subjected to a conventional genome-wide association analysis. CC1 associated with markers on linkage groups (LGs) 1, 2, 3, and 6, CC2 exclusively with markers in a genomic region on LG 2, and CC3 with markers on LG 1. BLAST alignment with the Brachypodium physical map revealed highly significantly associated markers with peak associations with genes adjacent and four genes away from the chromosomal locations of candidate SI genes, S- and Z-DUF247, respectively. Further significant associations were found in a Brachypodium distachyon chromosome 3 region, having shared synteny with Lolium LG 1, suggesting further SI loci linked to S or extensive micro-re-arrangement of the genome between B. distachyon and L. perenne. Significant associations with gene sequences aligning with marker sequences on Lolium LGs 3 and 6 were also identified. We therefore demonstrate the power of a novel association genetics approach to identify the genes controlling multi-locus gametophytic SI systems and to identify novel loci potentially involved in already established SI systems.
    • An Optimized Chloroplast DNA Extraction Protocol for Grasses (Poaceae) Proves Suitable for Whole Plastid Genome Sequencing and SNP Detection

      Diekmann, Kerstin; Hodkinson, Trevor R; Fricke, Evelyn; Barth, Susanne; Teagasc Walsh Fellowship Programme (PLoS, 30/07/2008)
      Background Obtaining chloroplast genome sequences is important to increase the knowledge about the fundamental biology of plastids, to understand evolutionary and ecological processes in the evolution of plants, to develop biotechnological applications (e.g. plastid engineering) and to improve the efficiency of breeding schemes. Extraction of pure chloroplast DNA is required for efficient sequencing of chloroplast genomes. Unfortunately, most protocols for extracting chloroplast DNA were developed for eudicots and do not produce sufficiently pure yields for a shotgun sequencing approach of whole plastid genomes from the monocot grasses. Methodology/Principal Findings We have developed a simple and inexpensive method to obtain chloroplast DNA from grass species by modifying and extending protocols optimized for the use in eudicots. Many protocols for extracting chloroplast DNA require an ultracentrifugation step to efficiently separate chloroplast DNA from nuclear DNA. The developed method uses two more centrifugation steps than previously reported protocols and does not require an ultracentrifuge. Conclusions/Significance The described method delivered chloroplast DNA of very high quality from two grass species belonging to highly different taxonomic subfamilies within the grass family (Lolium perenne, Pooideae; Miscanthus×giganteus, Panicoideae). The DNA from Lolium perenne was used for whole chloroplast genome sequencing and detection of SNPs. The sequence is publicly available on EMBL/GenBank.
    • A Pathogen-Responsive Leucine Rich Receptor Like Kinase Contributes to Fusarium Resistance in Cereals

      Thapa, Ganesh; Gunupuru, Lokanadha R.; Hehir, James G.; Kahla, Amal; Mullins, Ewen; Doohan, Fiona; Department of Agriculture, Food and the Marine; Science Foundation Ireland; 11/S/103; 10/IN.1/B3028; et al. (Frontiers, 2018-06-26)
      Receptor-like kinases form the largest family of receptors in plants and play an important role in recognizing pathogen-associated molecular patterns and modulating the plant immune responses to invasive fungi, including cereal defenses against fungal diseases. But hitherto, none have been shown to modulate the wheat response to the economically important Fusarium head blight (FHB) disease of small-grain cereals. Homologous genes were identified on barley chromosome 6H (HvLRRK-6H) and wheat chromosome 6DL (TaLRRK-6D), which encode the characteristic domains of surface-localized receptor like kinases. Gene expression studies validated that the wheat TaLRRK-6D is highly induced in heads as an early response to both the causal pathogen of FHB disease, Fusarium graminearum, and its’ mycotoxic virulence factor deoxynivalenol. The transcription of other wheat homeologs of this gene, located on chromosomes 6A and 6B, was also up-regulated in response to F. graminearum. Virus-induced gene silencing (VIGS) of the barley HvLRRK-6H compromised leaf defense against F. graminearum. VIGS of TaLRRK-6D in two wheat cultivars, CM82036 (resistant to FHB disease) and cv. Remus (susceptible to FHB), confirmed that TaLRRK-6D contributes to basal resistance to FHB disease in both genotypes. Although the effect of VIGS did not generally reduce grain losses due to FHB, this experiment did reveal that TaLRRK-6D positively contributes to grain development. Further gene expression studies in wheat cv. Remus indicated that VIGS of TaLRRK-6D suppressed the expression of genes involved in salicylic acid signaling, which is a key hormonal pathway involved in defense. Thus, this study provides the first evidence of receptor like kinases as an important component of cereal defense against Fusarium and highlights this gene as a target for enhancing cereal resistance to FHB disease.
    • A Pathogen-Responsive Leucine Rich Receptor Like Kinase Contributes to Fusarium Resistance in Cereals

      Thapa, Ganesh; Gunupuru, Lokanadha R.; Hehir, James G.; Kahla, Amal; Mullins, Ewen; Doohan, Fiona; Department of Agriculture, Food and the Marine; Science Foundation Ireland; 11/S/103; 10/IN.1/B3028; et al. (Frontiers, 2018-06-26)
      Receptor-like kinases form the largest family of receptors in plants and play an important role in recognizing pathogen-associated molecular patterns and modulating the plant immune responses to invasive fungi, including cereal defenses against fungal diseases. But hitherto, none have been shown to modulate the wheat response to the economically important Fusarium head blight (FHB) disease of small-grain cereals. Homologous genes were identified on barley chromosome 6H (HvLRRK-6H) and wheat chromosome 6DL (TaLRRK-6D), which encode the characteristic domains of surface-localized receptor like kinases. Gene expression studies validated that the wheat TaLRRK-6D is highly induced in heads as an early response to both the causal pathogen of FHB disease, Fusarium graminearum, and its’ mycotoxic virulence factor deoxynivalenol. The transcription of other wheat homeologs of this gene, located on chromosomes 6A and 6B, was also up-regulated in response to F. graminearum. Virus-induced gene silencing (VIGS) of the barley HvLRRK-6H compromised leaf defense against F. graminearum. VIGS of TaLRRK-6D in two wheat cultivars, CM82036 (resistant to FHB disease) and cv. Remus (susceptible to FHB), confirmed that TaLRRK-6D contributes to basal resistance to FHB disease in both genotypes. Although the effect of VIGS did not generally reduce grain losses due to FHB, this experiment did reveal that TaLRRK-6D positively contributes to grain development. Further gene expression studies in wheat cv. Remus indicated that VIGS of TaLRRK-6D suppressed the expression of genes involved in salicylic acid signaling, which is a key hormonal pathway involved in defense. Thus, this study provides the first evidence of receptor like kinases as an important component of cereal defense against Fusarium and highlights this gene as a target for enhancing cereal resistance to FHB disease.
    • Pathways for Nutrient Loss to Water; Slurry and Fertilizer Spreading

      Ryan, T. Declan; Holden, Nicholas M.; Carton, Owen T.; Fitzgerald, D.; Murphy, F.; Environmental Protection Agency (Teagasc, 08/07/2008)
      There are almost 150,000 farms in Ireland and these contribute substantial quantities of N and P to inland and coastal waters. Some of these nutrients are carried from wet soils by overland flow and by leaching from dry soils. Farm practice can reduce the loss from farms by judicious management of nutrients. Improvements are required to diminish export of nutrients without impairing operations on the farm. Literature regarding nutrient loss from agriculture was reviewed in this project and maps were prepared to predict best slurry spreading times around Ireland. Two further maps were prepared to show slurry storage requirement on farms.
    • Physiological and Transcriptional Response to Drought Stress Among Bioenergy Grass Miscanthus Species

      Vega, Jose J. De; Teshome, Abel; Klaas, Manfred; Grant, Jim; Finnan, John; Barth, Susanne; European Union; FP7-KBBE-2011-5-289461; CLNE/2017/364 (Biomed Central, 2020-07-28)
      Background: Miscanthus is a commercial lignocellulosic biomass crop owing to its high biomass productivity, particularly in the temperate regions. This study was conducted to elucidate physiological and molecular responses of four Miscanthus species subjected to well-watered and droughted greenhouse conditions. Results: A signicant biomass loss was observed under drought conditions for all genotypes. A sterile M. x giganteus showed a lower reduction in biomass yield under drought conditions compared to the control than the other species. Under well-watered conditions, biomass yield was as good as or better than control conditions in all species tested. M. sinensis was more tolerant than M. sacchariorus to both water stress conditions. 4,389 of the 67,789 genes (6.4%) in the reference genome were differentially expressed among four Miscanthus species. Most of the genes were differentially expressed in a single species, but the enrichment analysis of gene ontology (GO) terms revealed that the same biological processes were regulated in all the species during stress conditions. Namely, upregulated differentially expressed genes were signicantly involved in sucrose and starch metabolism, redox, and water and glycerol homeostasis and channel activity. Multiple copies of starch metabolic enzymes BAM and waxy GBSS-I were strongly up-regulated in drought stress in all Miscanthus genotypes. Twelve aquaporins (PIP1, PIP2 and NIP2) were also up-regulated in drought stress across genotypes. On the other hand, downregulated differentially expressed genes were signicantly involved in protein kinase activity, cell receptor signalling and phosphorylation. Conclusions: Findings in the present study can assist in implementing molecular breeding approaches of drought resistant Miscanthus and its domestication.
    • Plastid genome sequencing reveals biogeographical structure and extensive population genetic variation in wild populations of Phalaris arundinacea L. in north‐western Europe

      Perdereau, Aude; Klass, Manfred; Barth, Susanne; Hodkinson, Trevor R.; European Union; 289461 (Wiley, 2016-03-31)
      New and comprehensive collections of the perennial rhizomatous reed canary grass (Phalaris arundinacea) were made in NW Europe along north‐to‐south and east‐to‐west clines from Denmark, Germany, Ireland, Poland, Sweden and the United Kingdom. Rhizome, seed and leaf samples were taken for analysis and genetic resource conservation. A subsample covering the geographical range was characterized using plastid genome sequencing and SNP discovery generated using a long‐read PCR and MiSeq sequencing approach. Samples were also subject to flow cytometry and all found to be tetraploid. New sequences were assembled against a Lolium perenne (perennial ryegrass) reference genome, and an average of approximately 60% of each genome was aligned (81 064 bp). Genetic variation was high among the 48 sequenced genotypes with a total of 1793 SNPs, equating to 23 SNPs per kbp. SNPs were subject to principal coordinate and Structure analyses to detect population genetic groupings and to examine phylogeographical pattern. Results indicate substantial genetic variation and population genetic structuring of this allogamous species at a broad geographical scale in NW Europe with plastid genetic diversity organized more across an east‐to‐west than a north‐to‐south cline.
    • Pooled DNA sequencing to identify SNPs associated with a major QTL for bacterial wilt resistance in Italian ryegrass (Lolium multiflorum Lam.)

      Knorst, Verena; Byrne, Stephen; Yates, Steven; Asp, Torben; Widmer, Franco; Studer, Bruno; Kölliker, Roland; Swiss National Science Foundation; 31003A_138358 (Springer Science and Business Media LLC, 2018-11-30)
      Italian ryegrass (Lolium multiflorum Lam.) is one of the most important forage grass species in temperate regions. Its yield, quality and persistency can significantly be reduced by bacterial wilt, a serious disease caused by Xanthomonas translucens pv. graminis. Although a major QTL for bacterial wilt resistance has previously been reported, detailed knowledge on underlying genes and DNA markers to allow for efficient resistance breeding strategies is currently not available. We used pooled DNA sequencing to characterize a major QTL for bacterial wilt resistance of Italian ryegrass and to develop inexpensive sequence-based markers to efficiently target resistance alleles for marker-assisted recurrent selection. From the mapping population segregating for the QTL, DNA of 44 of the most resistant and 44 of the most susceptible F1 individuals was pooled and sequenced using the Illumina HiSeq 2000 platform. Allele frequencies of 18 × 106 single nucleotide polymorphisms (SNP) were determined in the resistant and susceptible pool. A total of 271 SNPs on 140 scaffold sequences of the reference parental genome showed significantly different allele frequencies in both pools. We converted 44 selected SNPs to KASP™ markers, genetically mapped these proximal to the major QTL and thus validated their association with bacterial wilt resistance. This study highlights the power of pooled DNA sequencing to efficiently target binary traits in biparental mapping populations. It delivers genome sequence data, SNP markers and potential candidate genes which will allow to implement marker-assisted strategies to fix bacterial wilt resistance in outcrossing breeding populations of Italian ryegrass.
    • Potato Breeding at Oak Park 2000-2006

      Dowley, L.J.; Griffin, Denis (Teagasc, 01/07/2009)
      The potato breeding programme at Oak Park was started in the 1960's and has consisted of a number of distinct phases. In the first phase the focus was on the evaluation of the main domestic and foreign varieties for suitability for the Irish market. This was followed by a breeding programme for the domestic market, with particular emphasis on the production of a blight resistant replacement for Kerr’s Pink. The emphasis then switched to breeding for the export market, with the focus on the UK and Mediterranean markets. Since then the breeding programme has been focused on both the domestic, processing and export markets. The process of breeding, testing and multiplying a new potato variety from the making of the initial cross until the new variety can be commercially grown takes about 15 years (see Appendix 1). This report covers the period 2001-2006 (RMIS NO 4720).
    • Potatoes and livelihoods in Chencha, southern Ethiopia

      Tadesse, Yenenesh; Almekinders, Conny J.M.; Schulte, Rogier P.O.; Struik, Paul C.; Wageningen University and Research; Vita (Irish Aid); Teagasc Walsh Fellowship Programme (Elsevier BV, 2018-06-18)
      Potato is highly productive crop and can provide a cheap and nutritionally-rich staple food. Its potential as a cash generator and source of food is much under-utilized in many emerging economies. In this paper we study the impact of an intervention that introduced improved potato technologies in Chencha, Ethiopia on the livelihoods of smallholder farmers. We collected information through in-depth interviews in order to explore possible pathways of impact on farmers’ livelihoods; and used this information as the basis for designing a household survey. The results show changes in agronomic practices and consumption; these changes were most pronounced among wealthy farmers who participated in the intervention. Farmers used the additional income from potato in different ways: wealthier farmers improved their houses and increased their livestock, whereas poor farmers mainly invested in furniture, cooking utensils, tools and in developing small businesses like selling and buying cereals, milk and weaving products in the local markets. Some wealthy farmers, who did not participate in the project, also derived some indirect benefits from the intervention. This underscores: i) interventions that promote uniform farming technologies in themselves are not always sufficient to improve the livelihoods of poor farmers, and ii) the need to broaden the scope of interventions so as to take into account the resources available to farmers in different wealth categories, and the diversity of strategies that they employ for improving their livelihoods. Our approach allows to understand and describe the different developmental effects of a single technological intervention on the different aspects of farmers’ livelihoods.
    • Potential for gene-flow from cultivated Irish grasses and cereals

      Mullins, Ewen; Ryan, Eimear; Meade, Connor (Teagasc, 01/08/2009)
      The importance of gene movement from cultivated plants has been highlighted in regard to minimising the movement of seed and/or pollen between GM and non-GM crops (i.e. gene flow). Although ryegrass covers in excess of 90% of Ireland’s agricultural area, very little is known about gene flow from ryegrass populations from an Irish context. The goal of this project was to address this lack of data by measuring the degree of pollen-mediated gene-flow between two Lolium spp. in a field environment. Ryegrass (esp. Lolium perenne) was selected because as the dominant pasture grass it is critical for the livestock industry as well as being a current target for novel improvements. The results from this research indicate that the potential for pollen-mediated gene flow from perennial ryegrass decreases exponentially with increased distance from the pollen source, with hybridisation events recorded out at 192m. In parallel to this research, a separate study was conducted to assess the degree of genetic diversity within feral and wild Lolium spp across Ireland and also within the important crop weed Avena fatua (‘wild oats’); thereby providing an insight into the degree of historic gene flow that has occurred within each species and in regard to the latter, identifying the potential for non-native A. fatua to colonise the Irish agrienvironment.
    • Precise Application of Fertiliser

      Forristal, Dermot; Plunkett, Mark (The Fertilizer Association of Ireland in association with Teagasc, 2017-05)
      The role of the fertiliser spreader is often under estimated in the delivery of fertilisers (N, P & K) as evenly and as accurately as possible. Fertilisers are a significant cost in grassland and tillage farming systems, representing between 20 to 30% of total production costs for either a cereal or grass silage crop. There are many steps involved in determining the actual rate of fertiliser from soil sampling to preparing a fertiliser plan. To profit from fertiliser planning it is essential that fertilisers are applied precisely and accurately. There are a number of factors to consider before spreading fertiliser such as: 1. Selecting the correct machine for the bout width and fertiliser to be used 2. Using good quality fertiliser 3. Correct setting of the machine Technical bulletin No. 3 produced by the Fertilizer Association of Ireland in conjunction with Teagasc identifies the steps to consider for the precise application of fertilisers to optimise farm profitability and sustainability.
    • Predicting soil moisture conditions for arable free draining soils in Ireland under spring cereal crop production

      Premrov, Alina; Schulte, Rogier P.; Coxon, Catherine E.; Hackett, Richard; Richards, Karl G. (Teagasc, 2010)
      Temporal prediction of soil moisture and evapotranspiration has a crucial role in agricultural and environmental management. A lack of Irish models for predicting evapotranspiration and soil moisture conditions for arable soils still represents a knowledge gap in this particular area of Irish agro-climatic modelling. The soil moisture deficit (SMD) crop model presented in this paper is based on the SMD hybrid model for Irish grassland (Schulte et al., 2005). Crop and site specific components (free-draining soil) have been integrated in the new model, which was calibrated and tested using soil tension measurements from two experimental sites located on a well-drained soil under spring barley cultivation in south-eastern Ireland. Calibration of the model gave an R2 of 0.71 for the relationship between predicted SMD and measured soil tension, while model testing yielded R2 values of 0.67 and 0.65 (two sites). The crop model presented here is designed to predict soil moisture conditions and effective drainage (i.e., leaching events). The model provided reasonable predictions of soil moisture conditions and effective drainage within its boundaries, i.e., free-draining land used for spring cereal production under Irish conditions. In general, the model is simple and practical due to the small number of required input parameters, and due to model outputs that have good practical applicability, such as for computing the cumulative amount of watersoluble nutrients leached from arable land under spring cereals in free-draining soils.
    • Quantitative trait loci associated with different polar metabolites in perennial ryegrass - providing scope for breeding towards increasing certain polar metabolites

      Foito, Alexandre; Hackett, Christine A; Stewart, Derek; Velmurugan, Janaki; Milbourne, Dan; Byrne, Stephen L.; Barth, Susanne; Department of Agriculture, Food and the Marine, Ireland; RSF 06–346 (Biomed Central, 10/10/2017)
      Background Recent advances in the mapping of biochemical traits have been reported in Lolium perenne. Although the mapped traits, including individual sugars and fatty acids, contribute greatly towards ruminant productivity, organic acids and amino acids have been largely understudied despite their influence on the ruminal microbiome. Results In this study, we used a targeted gas-chromatography mass spectrometry (GC-MS) approach to profile the levels of 25 polar metabolites from different classes (sugars, amino acids, phenolic acids, organic acids and other nitrogen-containing compounds) present in a L. perenne F2 population consisting of 325 individuals. A quantitative trait (QTL) mapping approach was applied and successfully identified QTLs regulating seven of those polar metabolites (L-serine, L-leucine, glucose, fructose, myo-inositol, citric acid and 2, 3-hydroxypropanoic acid).Two QTL mapping approaches were carried out using SNP markers on about half of the population only and an imputation approach using SNP and DArT markers on the entire population. The imputation approach confirmed the four QTLs found in the SNP-only analysis and identified a further seven QTLs. Conclusions These results highlight the potential of utilising molecular assisted breeding in perennial ryegrass to modulate a range of biochemical quality traits with downstream effects in livestock productivity and ruminal digestion.
    • Response of two-row and six-row barley to fertiliser N under Irish conditions

      Hackett, Richard (Teagasc (Agriculture and Food Development Authority), Ireland, 2016-12-30)
      A range of cultivar types, including two-row and six-row types as well as line and hybrid types, are used for winter barley production in Ireland. There is little information available on the fertiliser nitrogen (N) requirements or the N use efficiency of these different types, particularly under Irish conditions. The objectives of the work presented here were to compare the response to fertiliser N of a two-row line cultivar, a six-row line cultivar and a six-row hybrid cultivar in terms of grain yield and aspects of N use efficiency. Experiments were carried out over three growing seasons, in the period 2012-2014, on a light-textured soil comparing the response of the three cultivars of winter barley to fertiliser N application rates ranging from 0 to 260 kg N/ha. There was no evidence that cultivar type, regardless of whether it was a two-row or six-row line cultivar or a six-row hybrid cultivar, influenced the response to fertiliser N of winter barley. There were some indications that six-row cultivars were less efficient at recovering soil N but used accumulated N more efficiently than the two-row cultivar. This work provided no evidence to support adjustment of fertiliser N inputs to winter barley based on cultivar type