WP Leader: Dr. Gail TAYLOR (
The overall objective of WP 1 is to understand the genetic and genomic determinants of optimised yield in energy poplar and to test new genotypes suitable for breeding and gene stacking in WP3.
Previous work within the consortium has identified a set of high yield SRC poplar genotypes and these will be studied further in marginal poor agricultural soils to understand the basis of high yield in these conditions. We wish to test architectural and developmental traits alongside to key biochemical characteristics indicative of high water- and nitrogen-use efficiency and the allocation of biomass to wood. Here we will focus on one area of the Populus genome with QTL for yield traits detected in year 1, 2, 3 and 5 of SRC trial and also known to be important for yield in willow. We will utilise several years of investigation and data of Populus yield QTL that have given us good leads on the underlying genes determining yield and early diagnostic traits linked to yield. Using our preliminary findings and the eQTL database (SOTON) and further verification through microarrays and RT qPCR, we will investigate associations between below- and above-ground traits, and yield in Populus nigra where considerable research on quantifying genetic diversity has already been completed. Recent analysis of nucleotide diversity has revealed that although diversity is lower in P. nigra than in crop plants such as maize, it is still significant with levels of LD that should enable association mapping to be successful. Using a wide (‘diversity’) population of P. nigra that captures considerable natural genetic variation we will establish associations between genes and yield. We will initiate a programme to test functionality using transgenic approaches, from our own candidate genes involved in shaping root and shoot architectures, and using ideas already available from the literature. Both knock-down and over-expression are feasible in poplar (Boerjan, 2005) and once again the consortium has a rich set of resources already in place from which the project can benefit.
Our aim is to optimise yield – thus an understanding of the fundamental controls on traits determining water- and nutrient-use efficiency will be central to ensuring that the project is able to deliver information of relevance to the development of novel genotype in WP3. To address this, we are placing considerable efforts and resource into investigating the below-ground aspects of yield and resource optimisation, both for nutrients, including the role of ectomycorrhizal fungi and C sequestration, by considering the architecture and patterning of root growth.