African Journal of Soil Science

African Journal of Soil Science ISSN 2375-088X Vol. 5 (5), pp. 426-434, May, 2017. © International Scholars Journals

Review

Phenolics and their potential as biochemical markers for wheat rust and Russian wheat aphid resistance in South Africa

1Henry A Njom, 2Joyce Mebalo, 2Tarekegn G Terefe, 1,3Roland N Ndip, 1Graeme Bradley*

1Plant Stress Response Group, Department of Biochemistry and Microbiology, University of Fort Hare, Private Bag X1314, Alice 5700, South Africa,

2Agricultural Research Council, Small Grain Research Institute, Bethlehem, South Africa,

3Department of Microbiology and Parasitology, Faculty of Science, University of Buea, Box 63, Buea, Cameroon.

*Corresponding author. E-mail: gbradley@ufh.ac.za

Accepted 27 April, 2017

Abstract

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.

Keywords: Phenolics, disease, resistance, breeding, South Africa.