Wheat cultivars represent optimal combinations of genes to maximize yield, quality and disease resistance. In this sub-project we determined the ways in which important leaf rust resistance genes combine to confer disease resistance. Some of these genes are effective only against wheat leaf rust, while other such as Lr34 and Lr67 are multi-pest resistance genes which provide resistance to all of the rust pathogens of wheat and other diseases.  We found that both these genes work with other resistance genes to give a better and longer lasting form of resistance.  We also gained a better understanding of the molecular function of Lr34, which could be considered one of the single most important genes in the wheat genome.  Understanding the contribution of the various molecular forms of Lr34 will lead to more durable disease control in wheat.  Molecular markers were developed that will help select for many of the important rust resistance genes in future wheat cultivars.