Use of X-ray to evaluate damage caused by weevils in cowpea seeds

Abstract

In Brazil, the cowpea [Vigna unguiculata (L.) Walp], is important in the Northeast Region, where it is typically grown on family farms. The importance of the damage caused to the seed quality of this species by stored pests has been described in various studies. Using X-ray, it is possible to see the internal seed structures and identify possible changes and damage. The objective of this study was to identify the damage caused by the weevil [Callosobruchus maculatus (Fabr.)] by analyzing X-ray and evaluate its relationship to the physiological quality of the cowpea seed. Three cultivars were used (IPA-206, BRS-Pajeu and BRS-Potengi) and two lines (L 281.005 and L ESP 10). The samples were exposed to X-ray and germination test to determine the cause-effect relationship between weevil damage and seed germination. X-ray images were evaluated to determine damage severity and location in the seed. Seed damage classified as severe, located in the embryonic axis or in the cotyledons, resulted in abnormal seedlings or dead seeds. The X-ray test, therefore, is efficient for evaluating weevil damage in cowpea seeds and the damage caused to be associated with any resulting adverse germination effects.