description
- Most major changes in UK wheats, such as the introduction of dwarfing genes (which reduced plant height, but increased the yield) have been introduced from wide crosses. Wide crosses can still be used to introduce new genes which allow further major changes to be made in UK wheats. The proposal presented here will introduce new genes conferring longer ear rachis (= axis of the ear) associated with improved ear fertility from Mexican wheats (from CIMMYT) which could facilitate a quantum leap in overall yield in UK wheats. The material to test this has already been produced. Specifically, we have created a population of lines from a cross between the Mexican 'big-ear' line and a productive (highly efficient at turning sunlight into sugar) UK adapted wheat, Rialto. In a preliminary study, we have shown rachis length to be positively correlated with ear fertility (and grain number per unit land area). This proposal asks for funds to look at why the Mexican wheat produces more grain for each ear than UK wheat and whether we can use the same genes to improve UK wheat yields. The programme works with UK plant breeders from CPB-Twyford Ltd to produce wheat pre-breeding lines containing these new genes from the Mexican material. For breeders to introduce novel traits into elite UK varieties, they must first know which genes are responsible for controlling the traits and how they work to cause differences between varieties. So, we will map the genes controlling ear fertility and in doing so develop genetic markers to facilitate their selection in breeding programmes. The weather and environmental conditions can vary considerably between different countries and genes that may be useful in some countries may not be in others. We plan to carry out physiological experiments which would identify why the Mexican wheat has more grains in each ear and how this might help improve wheat yield in the UK varieties. We will also carry out experiments to examine whether these genes influence other important determinants of yield at the crop level, such as ear number and grain weight. Crucially, there should be added benefits due to the high photosynthetic ability of Rialto combined with more fertile ears in the 'big-ear' line. We already have seed from the crosses which are needed to do this work, but need funding to understand how wheat controls the number of grains produced per ear. Our industrial partner will use their breeding expertise to make new lines suited to UK breeding, and we will help develop these lines and also use these lines to help us understand the genetics of how many grains are produced per ear. Using this combined approach we will then identify a pool of candidate genes which may directly influence this trait.