Induction of Tetraploid Derivatives of Maize Inbred Lines by Nitrous Oxide Gas Treatment

Maize (Zea mays L.) is a model organism for various genetic and physiological studies. Induction of autotetraploid lines from elite inbred lines is valuable for investigating gene dosage effects on the molecular level. We applied nitrous oxide gas at the time of fertilization (30–36 h after pollination) for 20 h on maize inbred line Oh43. The nitrous oxide gas treatment between pressures of 600–1000 kPa proved to be effective in inducing tetraploids. The treatment also significantly increased the rates of germless and shriveled kernels. Twelve inbred lines were treated with nitrous oxide gas for 20 h at either 800 or 900 kPa pressures,30 or36 hafterpollination. Althoughtetraploidor tetraploid classaneuploidplantsfrom 9of 12inbredstestedwere successfully generated, only six genotypes produced progenies. The successful tetraploid inbred lines were from the A188, B73, H99, Oh43, Stock 6, and W22 genetic backgrounds. Aneuploids, plants with broken chromosomes and chimeras, were also found among the treated materials.