Comparing the Effectiveness of the “weevil warehouse” and “laboratory bioassay” as Techniques for Screening Maize Genotypes for Weevil Resistance

Abstract

The maize weevil (Sitophilus zeamais Motschulsky), causes devastating post-harvest grain losses, especially in tropical countries. Development of weevil resistant maize hybrids requires a rapid, inexpensive but effective screening method which can easily be incorporated in a maize breeding program without any advanced training in entomology. The current study compared the efficacy of weevil warehouse which is a kind of free-choice test with laboratory bioassay following a no-choice test, for discriminating maize genotypes into different weevil resistance/susceptibility classes. Fourteen maize genotypes were simultaneously screened using the weevil warehouse and the laboratory bioassay techniques. Results from both shelled grain and suspended ears under weevil warehouse assessments were compared with those from laboratory bioassay technique. Grain damage and grain weight loss were measured. High levels of consistency were detected during grouping of maize genotypes. The shelled grain option of the weevil warehouse and the laboratory bioassay screening methods were equally effective towards discriminating maize genotypes for their response to weevil attack (CVs of 7.1% vs 6.5% for grain damage and 12% vs 13% for grain weight loss, respectively). Therefore, the “weevil warehouse” technique, which is simple, inexpensive, time saving and precise would be recommended for rapid screening of maize germplasm for maize weevil resistance.