INVESTIGATIONS ON THE INHERENT RESISTANCE OF TWENTY-ONE MAIZE VARIETIES TO MAIZE WEEVIL, Sitophilus zeamais Motschulsky AT F2 GENERATION
GERALD M. UGAGU
Department of Science Laboratory Technology, Imo State Polytechnic, Owerri, Nigeria.
GODFREY M. PETGRAVE
Agronomy Unit, Precision Agriculture for Development, Boston, Massachusetts, USA.
OYINLOLA A. AJAYI
Department of Science Laboratory Technology, Federal Polytechnic Ede, Nigeria.
AKUBUIKE N. ELUWA
Department of General Studies, Federal College of Agriculture, Ishiagu, Nigeria.
LUKE C. NWOSU *
Department of Crop and Soil Science, University of Port Harcourt, Nigeria.
PETER I. ISIAKA
Department of Science Laboratory Technology, Imo State Polytechnic, Owerri, Nigeria.
BENJAMIN C. ONWUBUCHE
Department of Science Laboratory Technology, Imo State Polytechnic, Owerri, Nigeria.
NNAEMEKA K. OPARA
Department of Science Laboratory Technology, Imo State Polytechnic, Owerri, Nigeria.
BERTRAM E. B. NWOKE
Department of Animal and Environmental Biology, Imo State University, Owerri, Nigeria.
UWAOMA O. AGUWA
Department of Crop Science and Horticulture, Nnamdi Azikiwe University, Nigeria.
*Author to whom correspondence should be addressed.
Abstract
It has been internationally accented that use of resistant variety is a key strategy to save maize (Zea mays L.) grains from the pernicious activities of the maize weevil, Sitophilus zeamais Motschulsky (Coleoptera: Curculionidae). Therefore, twenty improved varieties and one local maize variety were studied in the laboratory using standard methods. The test varieties were selected because they are palatable, good-yielding and survive early season planting. Patterns of S. zeamais susceptibility index and adult mortality were plotted. Association between susceptibility index and adult mortality revealed that the two are connected in an inverse relationship. Eight varieties (38%) were resistant to S. zeamais attack. Aside allowing significantly minimal support for the survival and the development of S. zeamais, the varieties were consistently least damaged and lost. The cultivation and use of the resistant varieties identified will permit the postharvest storage of maize for long duration and reduce other problems associated with S. zeamais infestation. Thirteen moderately resistant maize varieties (62%) were revealed and their use under long storage condition should come with caution. The local maize variety had equivalent inherent moderate resistance with 57% of the varieties investigated. Most of the resistant maize varieties showed high viability when planted in the laboratory. This is an added advantage.
Keywords: Resistant variety, S. zeamais, postharvest, long storage, high viability