15-IWYP. A genetic diversity toolkit to maximise harvest index by controlling the duration of developmental phases

The project will identify new genes in bread wheat that will alter the timing of developmental well known landmarks in the wheat crop such as heading date and the crop maturity, but also more subtle changes, invisible in everyday observation of the wheat crop. These include stages in the very earliest days of the development of the wheat spike, which are crucial in determining the number of grains finally produced to build the foundations of new high yielding wheat varieties. The project is a collaboration between scientists in the UK, Argentina, Spain, Australia and the Centre for Improvement of Wheat and Maize (CIMMYT) based in Mexico. These partners will target an increase in yield potential in CIMMYT wheat, which reaches countries for which these improvements can do most to improve global food security.

Together with rice and maize, wheat forms the staple of the human diet (Braun et al. 2010). It is the most widely grown crop, and a vital component of the agricultural system on every continent except for Antarctica. As well as providing starch calories it is also the main source of plant protein for the global poor. Rates of genetic gain in wheat breeding are not sufficient to meet the demand for wheat (Rosegrant et al., 2013). Failure to address this problem will be catastrophic. An exciting proposition that could increase the rate of genetic gain for wheat is the efficient channeling of basic understanding of biological mechanisms controlling inflorescence development into a programme of breeding for grain yield by developing improved trait combinations delivering benefit in breeders' plots and farm fields. None of the traits that contribute to yield are better understood at the genetic level than flowering time and phenology (by which we mean here, the timing, duration, and environmental interactions of developmental phases of wheat inflorescence development). The work proposed here will further that understanding through the application of genetics, physiology and simulation modeling and will implement breeding interventions at several levels that can be used to maximise harvest index (HI) and yield in wheat.

The overarching IWYP goal is a 50% yield increase over 20 years. Therefore we have interpreted short, medium, and long term aspects as 5, 10, and 20 years respectively. We propose that, currently, the Harvest Index (HI) is ~40% globally in high potential environments with low levels of stress. In this diagram immediate project outputs are shown as orange arrows. Theyrepresent high biomass germplasm in which HI is increased using tools and knowledge (purple boxes with green text) generated here. This knowledge will be built upon and our approach will be extended in breeding to more efficient varietal improvement with our most tangible project outcomes such as new varieties shown in blue boxes. These will emerge first from CIMMYT and this will be a very direct consequence of mechanisms put in place here. The approach will be easily transferable to other spring wheat programmes and then, with further support and focus, in winter wheat. Commercial support and interaction will expedite this extension. The blue box outcomes will also be new ways of breeding so that the physiological and genetic dissection of phenology described here can be replayed in a synthesis step by which best trait combinations can be predicted and built afresh for new environments and within diverse pools of germplasm. The research direction established in this work and fully integrated into IWYP will accelerate scientific understanding of phenology and floral organogenesis relevant to wheat breeding because of their role in building sink strength, which in turn drives HI, so that mean global HI has increased to 50% after 10 years. The unique interaction between molecular, genetic, physiological, modelling, and breeding approaches causing the boundaries between these disciplines to blur, shown in green. Because all of the tools and resources, including germplasm and markers, will be made freely available to IWYP partners upon discovery/development the impact will be amplified. In twenty years the most striking outcome will be that the approaches established, now experimental, will be considered a routine element of wheat breeding essential to achieve IWYPs ambition and ingrained in breeding as almost tacit knowledge. The new understanding of yield per se applied to high potential environments for IWYP will be applicable under heat and drought, because the genetic and physiological basis of breeding progress made under IWYP will be understood, this transfer will be efficient. Together, these outputs will result in a mean global HI in drought free environments of 60% in 20 years.
The teams involved in the consortium have exceptional track records (see CVs) and deliver state of the art research and breeding in these areas. Much of the progress in phenology research of the last twenty years has been achieved by these groups. They are supported by excellent existing infrastructure, services, and management systems in host institutions so that all can engage fully in achieving the above goals with no infrastructural investment necessary from IWYP. Resources in germplasm, genomics, specialised methodologies, field experimentation platforms, skilled staff base, database structures are brought to the table from projects like ADAPTAWHEAT, WISP, WHEAT CRP, BBSRC GRO, CSIRO, and MasAgro. For these reasons the proposed work presents exceptional value for money, many of the concepts and methodologies employed are free from ongoing projects, so all involved can 'hit the ground running'.