Plant Genomics. Chapter 8: Genomic Approaches to Developing Molecular Markers Linked to Grey Leaf Spot Resistance Loci in Ryegrasses

Abstract

Ryegrass grey leaf spot (GLS), which is also called ryegrass blast, is caused by Magnaporthe oryzae (anamorph Pyricularia oryzae). It is a serious disease in ryegrasses including perennial ryegrass (Lolium perenne L.) and Italian ryegrass (L. multiflorum Lam.). Heavily infected young seedlings die within days, and grass stands can be seriously damaged by the disease. Thus, the development of GLS-resistant cultivars has become one of the most important objectives in ryegrass breeding. This chapter provides an overview of the current information regarding molecular marker development in the breeding of GLS-resistant ryegrass cultivars. It focuses on the pathology of GLS, heritability and breeding of GLS resistance, and development of molecular markers linked to a major ryegrass GLS resistance gene.