Effects of the pesticides Captan, Folpet, Guthion®, and Dichlorvos on recombination in maize ( Zea mays L.)

Abstract

This study was designed to determine if commercial preparations of the pesticides Folpet, Captan, Guthion®, and Dichlorvos, have a significant effect on genetic recombination in maize ( Zea mays L.). The pesticides were applied in aqeous solutions of 1.5% dimethyl sulfoxide with 0.04% X-77 Spreader®. Premeiotic treatment s to heterozygous females were applied as a foliar spray. Testcrosses were analyzed for changes in frequencies of recombination between loci 1 g− g12 and a- et on chromosomes 2 and 3, respectively. Sib-crosses were analyzed for changes in frequencies of recombination between the 1 g− g12 loci and the a2− bt loci on chromosomes 2 and 5, respectively. Between the a- et markers, significant increases in genetic recombination were produced by the 0.17 M level of Folpet, the 0.50 M level of Captan, the 0.50 M level of Guthion®, and the 0.66% v/v and 1.00% v/v levels of Dichlorvos. Between the a2− bt markers, significant increases in recombination were produced by the 0.33 and the 0.50 M levels of Guthion®. Analysis of variance for simple regression was conducted on each pesticide/marker group combination to determine possible linear dose responses. Significant increases in genetic recombination were induced linearly in the a− et linkage group with increasing levels of Captan, Guthion®, and Dichlorvos. Genetic recombination also was increased linearly in the a2− bt linkage group with increasing concentrations of Captan and Guthion®. The conclusion from this study is that commercial preparations of the pesticides Captan, Guthion®, Dichlorvos, and possibly Folpet, have the ability to increase the frequency of genetic recombination between markers of maize. This study therefore supports the consensus that certain pesticides, at abnormally high rates of application, are genetically active, environmental recombinagens.