Abstract

Henry A Njom, Joyce Mebalo, Tarekegn G Terefe, Roland N Ndip, Graeme Bradley

Three types of wheat rusts and Russian wheat aphid (RWA) are important constraints to wheat production in South Africa. Genetic resistance provides an effective and safe option to control these pests. However, breeding for resistance to rusts and RWA in South Africa largely depends on screening thousands of germplasm in the field at several localities. The success of such trials depends on optimum development of diseases and insects, which is mostly difficult to achieve due to seasonal variations in climatic conditions. Therefore, there is a need to improve this laborious and time-consuming screening method. Protective plant phenols, which are involved in resistance to biotic factors, are gaining more attention from plant breeders as potential biochemical markers. Such markers assist in overcoming the above limitations by allowing accurate and faster selection of resistant materials. For example, higher levels of phenolic compounds such as phytoalexins have been observed in resistant than in susceptible wheat cultivars suggesting that phenols may possibly be used as biochemical markers. This review paper discusses the different types of phenols, their significance in resistance to biotic factors and their potential application in breeding for resistance to wheat rusts and insects in South Africa.