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Ecological and genetic drivers of silicon accumulation in cereal crops Peetoom Heida, Isaac

Abstract

Over the past 30 years, the potential of silicon to improve crop plant performance has gained increasing recognition in the field of plant science. Silicon may be a key tool to guard crop production against uncertain future growing conditions by improving crop tolerance to abiotic and biotic stressors. In this thesis, I take recent advances in our understanding of silicon ecology and extend them into cereal crops, testing for the presence of rapid (< 24 hour) silicification in common Canadian crops after defence induction events, including herbivory, and used a genome-wide association study to identify potential genetic markers associated with high silicon content. We found that overall, simulated herbivory, but not cricket herbivory, increased silicon leaf content. However, at the species level, we found no significant increases in silicon content in response to herbivory treatments. This may be due to a silicon-poor soil environment or could reflect the effect of herbivore identity on specific defensive outcomes. In our genetic analysis, we found no genetic markers with significant associations to silicon content but did find a marker that had a significant correlation with manganese content. Our limited results may reflect the polygenic nature of silicon content in plants, or strong environmental effects. Future studies could build upon our results by developing a mapping population using genotypes we identified as representing the extremes of silicon content. Applications of silicon research into crop production techniques are still limited by crucial gaps in our understanding of how ecology and genetics control silicon uptake, but this work provides yet another steppingstone towards the broader adoption of silicon into agricultural systems.

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