Genetic variation and sterility percentages in adults of fall armyworm, Spodoptera frugiperda (Lepidoptera: Noctuidae) produced from gamma irradiated pupae

Abstract

The objective of the present study was to evaluate the molecular variation in adults of the fall armyworm, Spodoptera frugiperda (J.E. Smith) (Lepidoptera: Noctuidae) irradiated with doses 20, 40, 60 and 80 Gy as full-grown pupae. Results from RAPD-PCR showed that DNA fragments in the irradiated adults as pupae and unirradiated adults under investigation died. In the present study, six primers of  uniformed sequences were used to identify the genomic DNA of S. frugiperda. The weight of fragments varied from 185 bp to 1480 bp  when compared with unirradiated adults. In the study, irradiated adults were contrasted to unirradiated ones to explore any potential  variation to the DNA structure that may be induced by gamma radiation implementation. The data revealed polymorphic, monomorphic  and unique fragments in the fingerprints generated in the adults resulting from gamma irradiated pupae when compared with the  unirradiated adults. Additionally, the highest number of amplified fragments was 28 generated from the two primers, OP-C15 and OP-D1;  whereas the lowest number of amplified bands was 16 generated from primer OP-B3 in gamma irradiated adults. Primer OP-C9  showed the lowest value of similarity index 0.28 between unirradiated adults and irradiated adults as pupae with 80 Gy which reflects the  highest degree of alteration in DNA sequence and arrangement. Gamma irradiation of the parent generation induced different sterility  levels in the offspring, females were more radiosensitive than males. These results are encouraging and indicate that inherited sterility  might be used for control of this pest. Large field experiments should be implemented to confirm the laboratory findings.