Are variations in kernel-related morphometric and chemical parameters correlated with differences in Sitophilus oryzae attack in maize?

Abstract

Insect infestation during seed storage affects cereal productivity. Sitophilus oryzae, which is present in various climates, is one of the primary pests for maize (Zea mays) seeds. In this study, kernels of a set of eight inbred lines of importance for both maize breeding and research activities were characterised for morphological and biochemical parameters as well as for their susceptibility to S. oryzae. S. oryzae was reared in laboratory- controlled conditions and the susceptibility index (SI, range: 0-11), which depends on both number of emerging adults and their median developmental period, was measured. Maize kernels of each of the eight maize lines were put in contact with less than 3-day old males and females of S. oryzae for 13 days. Infested kernels were checked daily for new adult emergence. Four maize lines were susceptible to S. oryzae attack (SI = 7.5 to 9.7) while the others appeared to be moderately resistant (SI = 4.6-6.9). Our results highlighted the occurrence of variability for insect susceptibility among different maize genotypes, however, variations in the kernel traits analysed do not allow us to make predictions about the response to insect attack.