Improving bioenergy crop yield and quality through manipulating senescence

Senescence impacts harvestable biomass yield and quality in Miscanthus. Very earlyautumn senescence shortens canopy duration reducing yield potential. When senescence is too late or slow, the crop does not ripen sufficiently before harvest, resulting in high moistureand nutrient content in harvested material that reduces biomass quality and affects cropsustainability. In this study, variation in senescence was monitored over 3 years in a trialof 244 Miscanthus genotypes planted in four replicate blocks. To test the hypothesis thatthrough optimal timing of senescence it is possible to achieve high biomass accumulation and high crop quality, the progression of senescence was correlated to moisture contentand interactions between senescence and yield studied in all years. To optimise crop yield and quality in different regions we need to better understand andidentify the variation in the control of senescence. Senescence is a complex trait that isdifficult to assay, particularly at the level of whole plant senescence necessary for bioenergycrops in which the whole above ground crop is harvested. We have tested high-throughputand quantitative analysis techniques that may contribute to improved senescence studiesincluding detached leaf assays, digital image analysis and gene expression. This studyprovides information for the future optimisation of Miscanthus, and potentially other energygrasses, where new varieties are needed to maximise net energy yields and crop quality.