Molecular Investigation Using RAPD-PCR Marker Field Populations of Pectinophora gossypiella Saunders (Lepidoptera: Gelechiidae) Exposed to Some Insecticide

Seasonally the cotton plant cultivated in Egyptian fields is suffering from the cotton Pink Bollworm Pectinophora gossypiella (Saunders) (Lepidoptera: Gelechiidae) attacking fruits and buds. Insecticide applications reported control failure by the most recommended conventional classes. Monitoring pest DNA changes after sublethal exposure become the new technique to investigate. Then four insecticide treatments were screened by using the molecular marker polymerase chain reaction (PCR) inspection, using four Random amplified polymorphic deoxyribonucleic acid analysis (RAPD-PCR) primers partitioned based on band reproducibility. Result of LC50 was 0.55, 61.1, 69.3, and 0.23 for spinoteram, novaluron, metaflumezone, and dimeuron respectively. The insecticide treatments band of gel produced detected 47 loci ranging from 87 to 63 % polymorphism. The primer efficiency value of PIC =0.361, 0.34, 0.34, 0.355, and 0.262, RP = 5.30, H = 0.473, 0.434, 0.434, 0.462 and 0.31, and MI = 0.10, 0.1386, 0.138, 0.167 and 0.0582 for the same treated samples respectively. Distance and similarity were quantified based on Nei’s and genetic dissimilarity by the UPMGA method then a phylogenetic tree was constructed and grouped the entire genotypes into 2 major clusters and 6 subclusters. The RAPD primers revealed the number of alleles (Na = 0.324, 0.318, 0.318, 0.326, and 0.328), and the effective number of alleles (Ne = 0.571, 0.569, 0.558, 0.574, and 0.5784). The fixation-index (Fst) analysis narrated a very great genetic diversity (Fst = 0.626, 0.684, 0.684, 0.2, and 0.695) exists within the four treated samples respectively. The level of gene flow was (Nm = 0.239, 0.230, 0.230, 0.233, and 0.2187) respectively across the four genotypes studied. Results proved that the RAPD-PCR technique was suitable for distinguishing between insecticide treatments.