Understanding germination for improved propagation and field establishment of the bioenergy crop Miscanthus

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Student thesis: Doctoral ThesisDoctor of Philosophy

Original languageEnglish
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Award date2017
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Abstract

Miscanthus is an important source of biomass and can be grown on marginal sites so as not to compete with food crops. The crop requires few inputs, is perennial, and yield increases to economic levels over around three years, so Miscanthus must be cost effective to establish. Establishment by seed is more cost effective than by rhizome; therefore, improving seed agronomy is vital for the success of the crop. This study contributes an assessment of many previously unknown factors on Miscanthus germination. Hormone treatments and cluster sowings are tested, predominantly for direct sowing but also for plug-based establishment. Cluster sowings improved the chance of establishing a plot, some first year competition effects were identified; however, the number of seeds required may not be economic without additional treatments. An optimal set of treatments for successful germination was identified using a Taguchi design experiment. Complex hormone interactions were tested plus effects of light and seed priming. Methodologies and automation of seed germination assessment were developed. The unreliability of manual seed germination scoring with highlighted and germination scoring was only assisted by imaging due to low throughput. A selection of Miscanthus genotypes were characterised, for base temperatures of germination and elongation. From this information, a model was parameterised for Miscanthus seed germination; this was tested against different sowing methods in field and laboratory conditions and against real data collected from experiments that tested first year agronomic methods, such as sowing time, film, and seed priming. Film was found to have positive temperature effect but mixed effects on germination due to soil water, while priming had little benefit. This model can be used and refined further to test and develop hypotheses for future improvements in seed agronomy.