Now showing 1 - 1 of 1
  • Publication
    Optimising the agronomic management of spring andwinter-sown oats (Avena sativa) for milling
    (University College Dublin. School of Agriculture and Food Science, 2021) ;
    Agronomic research in oats has been inhibited due to limited acreage and higher interest in other cereal crops, but recent recognition of the dietary health benefits of oats have led to a rekindled interest in the crop. This study presents the findings of a four-year research project into the agronomic and genetic factors affecting the production of milling oats under Irish conditions. This study aims to identify and quantify crop responses to agronomic inputs both in grain yield and grain milling quality, while also investigating the potential to breed and select disease resistant cultivars. The key agronomic parameters of cultivar, seed rate, applied N fertilizer rate and application of plant growth regulators were investigated in factorial trials with grain yield, yield components and grain quality effects recorded in winter and spring oats. In a separate set of factorial trials, the effects of N rate and application timing were investigated on spring and winter oats. Cultivar selection was of importance in the attainment of high grain yield due to genetic yield potential, with seed rate and applied N rate increasing yield through increases in grain number. Application of N during early developmental periods resulted in increased grain yield due to increases in panicle number and grains/panicle, with late application of N resulting in increased grain protein. Significant lodging at higher input levels justifies the inclusion of PGR application as a management tool, with significant yield responses observed. Cultivar choice was shown to be a key contributor to grain quality in line with previous reports, with the agronomic effects of PGR application and seed rate of minor importance. Applied N had significant effects on grain hullability due to reductions in kernel size, while grain protein also increased. Groat percentage was predominantly determined genetically, with climatic conditions during grain-fill of greater importance than any agronomic factor. A diallel cross was completed to determine the genetic nature of powdery mildew resistance in selected cultivars. These diverse cultivars were assembled and grown under Irish conditions with powdery mildew resistance successfully identified and transferred. Combining ability analysis indicated the importance of specific combining ability for powdery mildew resistance in the cultivars selected. These crosses were examined for segregation of resistance genes in the F2 generation, with crosses between resistant and susceptible genotypes resulting in inheritance patterns indicative of dominant gene action. Crosses between resistant genotypes resulted in distributions with no susceptible phenotypes, indicating the genes controlling the exhibition of resistance in these cultivars are inherited separately. This study has two key focus areas, Agronomy and Genetics. The significance if the agronomic study lies in the key responses to applied N rate, N application timing and cultivar selection over a large number of experiments while highlighting that the agronomic issues of lodging and climatic conditions have not yet been genetically mitigated. The significance of the genetic study is the successful identification of R genes in relevant cultivars and the potential to develop oat varieties with lower chemical input requirements.