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Frequency of Cry1F resistance alleles in Spodoptera frugiperda (Lepidoptera: Noctuidae) in Brazil
Author(s) -
Farias Juliano R,
Andow David A,
Horikoshi Renato J,
Bernardi Daniel,
Ribeiro Rebeca da S,
Nascimento Antonio RB do,
Santos Antonio C dos,
Omoto Celso
Publication year - 2016
Publication title -
pest management science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.296
H-Index - 125
eISSN - 1526-4998
pISSN - 1526-498X
DOI - 10.1002/ps.4274
Subject(s) - spodoptera , noctuidae , lepidoptera genitalia , allele , biology , resistance (ecology) , allele frequency , confidence interval , population , veterinary medicine , botany , agronomy , genetics , mathematics , statistics , demography , gene , recombinant dna , medicine , sociology
BACKGROUND The frequency of resistance alleles is a major factor influencing the rate of resistance evolution. Here, we adapted the F 2 screen procedure for Spodoptera frugiperda (J. E. Smith) with a discriminating concentration assay, and extended associated statistical methods to estimate the frequency of resistance to Cry1F protein in S. frugiperda in Brazil when resistance was not rare. RESULTS We show that F 2 screen is efficient even when the resistance frequency is 0.250. It was possible to screen 517 isoparental lines from 12 populations sampled in five states of Brazil during the first half of 2012. Western Bahia had the highest allele frequency of Cry1F resistance, 0.192, with a 95% confidence interval ( CI ) between 0.163 and 0.220. All other states had a similar and lower frequency varying from 0.042 in Paraná to 0.080 in Mato Grosso do Sul. CONCLUSION The high frequency in western Bahia may be related to year‐round availability of maize, the high population density of S. frugiperda , the lack of refuges and the high adoption rate of Cry1F maize. Cry1F resistance alleles were not rare and occurred at frequencies that have already compromised the useful life of TC1507 maize in western Bahia. © 2016 Society of Chemical Industry