A review of breeding for resistance to maize streak virus disease in sub-Saharan Africa.

Abstract

Meeting the food demand for the teeming population is a herculean task in sub-Saharan Africa (SSA), where population growth rate is rapid at the expense of crop productivity. Maize is a staple food for millions of people but yield per unit area is limited by an array of biotic and abiotic factors. Among the several viruses infecting maize, Maize streak virus (MSV; genus Mastrevirus, family Geminiviridae) is the most economically important in the sub-region. Maize streak virus induces white chlorotic streak on the leaves of infected plants, necrosis, dieback, stunting and sterility. Incidence and yield losses vary from 0 to 100 % depending on the level of tolerance or susceptibility of the maize germplasm. Resistance to MSV infection is conditioned by monogenic or oligogenic genes. Of the various control strategies recommended, adoption of genetically resistant cultivars is the most cost-effective, efficient and sustainable. Breeding for MSV resistance is accomplished using conventional or Marker-Assisted Breeding (MAB). In addition, transgenic MSV tolerant maize plants have been developed using the mutated MSV replication associated gene. This paper reviews the current status of breeding activities for maize streak virus disease resistance in sub-Saharan Africa