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Genetic variability of the European corn borer, Ostrinia nubilalis, suggests gene flow between populations in the Midwestern United States

Author:
Krumm, Jeffrey T., Hunt, Thomas E., Skoda, Steven R., Hein, Gary L., Lee, Donald J., Clark, Pete L., Foster, John E.
Source:
Journal of insect science 2008 v.8
Subject:
Ostrinia nubilalis, population genetics, molecular genetics, amplified fragment length polymorphism, genetic variation, geographical variation, gene flow, ecotypes, univoltine habit, multivoltine habit, Midwestern United States
Abstract:
The European corn borer, Ostrinia nubilalis (Hübner) (Lepidoptera: Crambidae), is a widely distributed and serious economic pest to corn production in the U.S. Genetic variability of O. nubilalis was studied in 18 sub-populations in the upper Midwestern United States using amplified fragment length polymorphism. The relatively low GST values indicate that more variation exists within populations than between populations. High gene flow (Nm) values were indicated across the entire O. nubilalis population; the lowest degree of gene flow was in the northern samples (Nm = 1.96) and the highest degree of gene flow was in the southern samples (Nm = 2.77). The differences observed in the respective regions (north vs. south) may be explained by the voltinism patterns (univoltine vs. multivoltine, respectively) of O. nubilalis: southern multivoltine populations have opportunities for multiple matings for the duration of the year, further mix alleles. AMOVA results also indicated that most of the genetic variation was within sub-populations (approximately equal to 81% of total variation); less variation (approximately equal to 13%) was detected among populations within each of the three regions as designated for this study. However, the most striking and unexpected result was the low percentage of variation between all groups (approximately equal to 6%), further supporting implications of a high degree of gene flow. These results provide support for current requirements of refugia corn planting in Bt-corn management. These results also indicate that if resistance to Bt were to evolve in O. nubilalis, quick action would be necessary to deter the rapid spread of the gene for resistance.
Agid:
27493
Handle:
10113/27493