Molecular Improvement of Disease Resistance in Barley (MIDRIB)

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This project develops an approach, genomic selection, to increase the rate at which varieties of Spring barley are developed. This is a very important crop in national agriculture, particularly for the malting, brewing and distilling industries. It is important that the rate with which improved varieties are created is increased so that more effort can be placed by breeders on improving disease resistance while maintaining or increasing grain yield and grain quality, which remain of greatest importance to growers and end users.Genomic selection represents a way of predicting traits purely from genetic markers rather than by direct measurement. These predictions require that a set of plants is first measured for the target traits so that the effect of each marker can be estimated. However, after that, selection can occur for several generations purely on markers.Direct measurement of many traits can take much longer than a single growing season: seed must first be bulked up over several generations to provide a sufficient quantity for yield trials. In contrast, marker data can be collected within the generation time of any crop and is therefore much faster than conventional selection.Other approaches to plant breeding using genetic molecular markers have been in use for many years. In these, a very small numbers of markers with strong evidence of an affect on a trait are first identified. These are then tracked through the breeding programme. Genomic selection differs in that all available markers are used to predict traits: the more markers the better. The inclusion of all markers gives more accurate prediction of overall trait values even though the precise involvement of each marker is known with less certainty.Our study has four themes. Firstly, throughout the life of the project, we shall develop new statistical methods to establish relationships between very high numbers of genetic markers and traits. The methods we develop will be more focussed on the problems of plant breeding: most methods to date have been targeted at animal breeding. Secondly, we shall test methods which are available now using historical data available from to an existing Spring barley scheme. Results will be used immediately to make selections within this scheme. We expect to register new varieties from these selections within the five year life of the project.Next, we shall use results from the analysis of the historical data together with any early methodological developments we make to create crosses specifically to exploit genomic selection. These crosses may not necessarily be the typical crosses between two parents which are commonly used by breeders but may involve more complicated crossing schemes involving, for example four parents. Within the life of the project, we shall test whether this approach gives a greater response to selection that achieved by more conventional breeding, but there will be insufficient time to resister a new variety.Finally, we shall integrate results and methods from the first three phases to completely redesign the breeding programme to get the greatest advantage out of genomic selection.In short, we plan to develop a new approach to Spring barley breeding .Genomic selection could result in a fundamental change to the way crops are bred and enable targets for increased food production and environmental sustainability to be met. Compared to other temperate crops, Spring barley has a short generation time which make it well suited to develop and test these ideas, which may also be applicable to other crops.