Pre-Breeding at NIAB - Ppd alleles and markers QTL for earliness per se and novel variation from synthetic wheat useful to UK/EU wheat improvement

For the future, plant-based processes offer sustainable solutions to many of the nutritional, health and environmental challenges that face humankind. The UK has an extremely strong and vibrant plant science research community with many internationally competitive research groups based in the universities and institutes. Whilst their discoveries have the potential to impact on the key sustainability issues such as the supply of high quality nutritious food, response to climate change and identifying sources of bioenergy, it is evident that translation to successful outcomes suffers from the lack of an effective delivery mechanism to end users. It is against this backdrop that NIAB is investing £1.25 million over 5 years to establish a Centre for Pre-Breeding that will provide a product conferring capability available to all UK researchers and end-users. The Centre will develop a unique platform for delivery of novel traits and associated marker technologies in wheat, oilseed rape, pulses and selected non-food crop applications. Trait genes and markers will be validated in pre-competitive, UK adapted germplasm that can be accessed by commercial breeders and end-users in the non-food area. The Centre will not produce finished varieties and hence won't compete with commercial breeders. NIAB's investment will be used to establish infrastructure and initiate longer-term pre-breeding activities. Funding from this initiative is sought to support pre-breeding in two key areas that address key targets in sustainability of the wheat crop in the UK. Firstly, we will exemplify the translation of a research breakthrough in publicly funded science to practical outcome. The wheat gene Ppd uses day length as a cue to determine when the plant flowers. It is a key adaptability gene; breeders can use variants of the gene to produce varieties that match local environments. An early flowering variety is better suited to hot dry summers where it is important to fill grain before water is scarce and temperatures soar. Conversely, a delay in flowering sustains yield in cooler and wetter summers, such as those generally experienced in the UK, with a longer period suitable for grain filling. The Laurie group at the John Innes Centre has recently identified three Ppd genes in wheat. In the research proposed here, we will provide the molecular markers for these genes and important new data on their developmental effects. Importantly, there is more to this work than simply accelerating the breeding process; new Ppd variants and flowering time genes will be identified and characterised. This novel variation will be fundamental in providing alternative genes that breeders can exploit to tune flowering in varieties in response to global warming and climate change. Secondly, we will establish a platform for introducing novel variation across a range of wheat traits based on exploitation of a collection of synthetic wheats from the International Centre for Maize and Wheat Improvement (CIMMYT) in Mexico. The conventional view is that the genetic base for wheat improvement in the UK and Europe is very narrow. Synthetic wheats address this issue as they recreate the rare hybridisations that gave rise to the progenitors of our modern bread wheats but dramatically increase genetic diversity by using a range of parents. NIAB will initiate a crossing programme with selected synthetic wheats and varieties from CIMMYT that have a synthetic origin. The objective is to deliver pre-breeding materials to commercial breeders that provide novel traits in key sustainability targets such as novel pathogen and insect pest resistance, biomass and yield potential and tolerance to drought. This work will be undertaken in close collaboration with UK industry facilitated by the British Wheat Breeders and the HGCA and represents the open 'public-private partnership' that will define how the pre-breeding Centre at NIAB operates across all crop targets.

This project is divided into three work programmes that will deliver pre-breeding outputs. The first will exploit the recent identification of the three wheat Ppd genes (the major determinants of photoperiod response) by the Laurie group at JIC and will: 1 characterise the extent of allelic variation for wheat Ppd 2 develop molecular markers to aid breeding 3 develop near isogenic lines with principal allelic variants to characterise developmental effects attributable to individual alleles. This will provide a robust data set linking individual Ppd alleles to effects on flowering time, ear development and yield potential. Donor germplasm for novel alleles will have been defined and diagnostic molecular markers for all allelic types will aid rapid exploitation by commercial breeders. In the second work programme, we will investigate other loci known to affect flowering time; These 'earliness per se' (Eps) genes are important because they can fine-tune development and adaptation, but this class of genes are very poorly understood. We will use existing mapping populations and data for current varieties to localise Eps genes and quantify their effects. This will provide information on Eps loci that complements Ppd, define their effect on wheat development and identify of sources of variation and linked markers. In the final work area, we will undertake a crossing programme from CIMMYT synthetic hexaploid wheat (SHW) lines and CIMMYT varieties derived from SHW into UK adapted germplasm. Between 30 and 40 non-redundant SHW will be crossed to an adapted UK wheat to the BC1F2 and then by single seed descent to F5 generating 100 inbred donor lines per original cross. From ten SHW derived varieties, donor segments will be identified by genotyping and transferred by backcross introgression to a UK wheat. After seed multiplication, all lines will be tested for key agronomic and sustainability traits, including drought tolerance.