A Comparative Analysis of Conventional and Marker-Assisted Selection Methods in Breeding Maize Streak Virus Resistance in Maize

Reliable information regarding comparative advantage of marker-assisted selection (MAS) over conventional selection (CS) in breeding for maize streak virus (MSV) resistance in maize (Zea mays L.) is scarcely available. A comparative study was, therefore, conducted to determine the efficiency of both methods in breeding for MSV resistance in Uganda. Backcross and selfed-progenies were derived from inbred lines CML202 (resistant), CML321, and CML384 (susceptible) using MAS and CS. The experimental lines and their testcross progenies were evaluated for MSV resistance and yield across three locations. Although both breeding approaches were effective in generating MSV-resistant lines, disease incidence was higher in populations under CS (79%) than MAS (62%). A similar trend was observed for area under disease progress curve. However, an equal number of lines generated by MAS and CS displayed high yield potential and MVS resistance in testcrosses. Because all required DNA analysis was performed in an existing laboratory and on a well-characterized quantitative trait locus, costs of capital, equipment maintenance, and marker development were excluded in costing the MAS procedure. Considering total running costs, MAS was cheaper than CS by 26%, which was realized by using fewer plants. Therefore, when laboratory facilities are already established MAS would be recommended in breeding for MSV resistance.