Doubling Efficiency of Maize Haploids Treated by Different Herbicides

The objective of this investigation was to explore a new technology of doubling maize haploids using herbicides. Maize haploids used in this research were induced from three hybrids: Pioneer 335, N-D 4, and 8607×8609. Herbicides, Amipro-phos-methyl (APM), pronamide and trifluralin with the concentration of 20, 40, 80, and 160 μmol L?1, respectively, were used for doubling the haploids by drop into the interior leaf whorls of the haploid from the 3-leaf stage to the 5-leaf stage. The haploid plants having pollens were self-pollinated during the pollen shedding stage and the doubling rates of three herbicides were inves-tigated at the mature stage. Both chromosome number of root tip cells and pollen fertility among sampling haploid plants were analyzed. The results showed that all three herbicides had effects on doubling haploids with the rates of 3.42% and 26.32%. The doubling rates of haploids from Pioneer 335, N-D 4 and 8607×8609 were 4.29–26.32%, 3.85–20.81%, and 3.42–17.61%. The doubling rates of haploids from Pioneer 335, N-D 4 and 8607×8609 teated by 80 μmol L?1 APM were 25.02%, 20.13%, and 14.99%, respectively. The results showed that there were significant differences between Pioneer 335 and N-D 4, Pioneer 335 and 8607×8609, and N-D 4 and 8607×8609 for the doubling rates. To sum up, APM, pronamide and trifluralin all have significant effect on doubling maize haploids and the sensitivity of maize haploids from diverse sources to the same herbicide is different.