Epidemiology and molecular characterization of quantitative trait loci (QTLs) for resistance to common rust (Puccinia sorghi) and gray leaf spot (Cercospora zeae maydis) diseases of maize in Ethiopia

Abstract

Maize (Zea mays L.) is an important component of farming systems and staple food crop in sub-
Saharan Africa. In Ethiopia maize is a staple food and one of the main sources of calories in the major
maize producing regions. It is cul vated on about 1.7 million hectares of land. The national average yield
of maize under subsistence produc on is about 2200kg/ha. This is too much below the world’s average
yield. This low yield is attributed to foliar diseases and insect pests such as stalk borer. One of the bottle
necks in developing countries like Ethiopia which have lowered the yielding ability of maize is the usage of
inferior genes which are susceptible to diseases, insects, weeds, low yield and quality. Another is lack of
adequate investment and skilled manpower to improve varieties for high yield and disease resistance,
diminishing land and water resources and environmental stresses. The most common potentially
economic diseases on maize in Ethiopia are common rust and gray leaf spot. Despite the presence of
food shortage in Ethiopia, every year a heavy toll of maize yield is taken by these pathogens. For example,
23% yield reduc on by common rust and 37% loss by gray leaf spot were recorded. Genomic research can
provide new tools and resources to revolutionize crop genetic improvement and production. Recognizing
the enormous potential of DNA markers in plant pathology and breeding, many agricultural research
centers with plant pathology and breeding institutes in developed countries have adopted the capacity
for marker development and marker-assisted selection (MAS) and due to rapid developments in marker
technology, statistical methodology for identifying quantitative trait loci (QTLs) and the jargon used by
molecular biologists, the utility of DNA markers in plant pathology and breeding is clearly understood by
molecular biologists. But these technologies are scanty in Ethiopia. Therefore, in this review epidemiology
of these pathogens and molecular approaches helpful in boosting maize productivity were discussed.
Hence, this information can help plant pathologists, plant breeders and geneticist to promote further
studies in this new research area in Ethiopia.