description
- With the global population set to reach nine billion by 2050, there is an urgent need to increase food production by at least 60%. Wheat production has plateaued in many areas of the world due to a lack of novel genetic variation for agronomically important traits compounded by the effects of climate change. The lack of genetic variation in modern wheat is a direct consequence of significant genetic bottlenecks during its evolution. As a result, the amount of genetic variation for agronomically important traits available in wild ancestors and landraces of wheat is significantly greater than in present day elite varieties. In contrast to modern wheat, its distant relatives provide a vast resource of genetic variation for potentially all agronomically important traits, including photosynthesis. However, only a fraction of the genetic variation available has been exploited in breeding programmes. There is now recognition that improved grain yields of major crops require enhanced total dry weight production which must arise mostly from an improvement of radiation-use efficiency (RUE). Raising RUE requires a higher leaf and canopy photosynthesis rate and this remains an important target to underpin future yield progress. There is compelling evidence that C3 photosynthesis is not optimized for high biomass and moreover there is unrealized genetic potential. The fastest way to raise photosynthesis by genetic improvement in wheat is to seek existing variation in relevant traits that can be used for breeding and pre-breeding. This may represent new variation in photosynthesis that was either lost from the wheat genome during breeding or never present. Traits include (1) properties of Rubisco (2) regulation of Rubisco activity, (3) photoprotective processes (4) electron transport/ RuBP regeneration (5) photorespiration (6) canopy structure and distribution of photosynthesis and pigments (7) internal leaf and chloroplast morphology (8) stomatal responses (to soil and atmospheric water) and leaf water use efficiency. objective of the programme at Nottingham is to transfer small chromosome segments from related species which carry a target gene but lack any deleterious genes, into wheat. In this project we will generate, using wide crosses, landraces and existing cultivars, lines with substantial variation in their photosynthetic properties and use high throughput screening techniques to identify progeny with enhanced photosynthetic capacity and efficiency. We will investigate the genetic basis of the photosynthetic variation and with the IWYP HUB integrate these discoveries into a pre-breeding and breeding strategy. The programme will bring together a multi-disciplinary research team: UoN (wide crossing, wheat physiology, photosynthesis phenotyping), (UoB: Genetic marker analysis), University of Essex (UoE: novel photosynthesis phenotyping, Calvin cycle engineering), Lancaster University Environment Centre (LEC: whole plant carbon gain and water use, Rubisco engineering), CIMMYT (field phenotyping and genotyping).