Improving bioenergy crop yield and quality through manipulating senescence

Abstract

Senescence impacts harvestable biomass yield and quality in Miscanthus. Very early autumn 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 moisture and nutrient content in harvested material that reduces biomass quality and affects crop sustainability. In this study, variation in senescence was monitored over 3 years in a trial of 244 Miscanthus genotypes planted in four replicate blocks. To test the hypothesis that through optimal timing of senescence it is possible to achieve high biomass accumulation and high crop quality, the progression of senescence was correlated to moisture content and interactions between senescence and yield studied in all years. To optimise crop yield and quality in different regions we need to better understand and identify the variation in the control of senescence. Senescence is a complex trait that is difficult to assay, particularly at the level of whole plant senescence necessary for bioenergy crops in which the whole above ground crop is harvested. We have tested high-throughput and quantitative analysis techniques that may contribute to improved senescence studies including detached leaf assays, digital image analysis and gene expression. This study provides information for the future optimisation of Miscanthus, and potentially other energy grasses, where new varieties are needed to maximise net energy yields and crop quality.