Doubling effect of anti-microtubule herbicides on the maize haploid

Doubled haploid (DH) technology is widely used in crop breeding programs. Colchicine is the most frequently used chemical agent in the DH inducing. However, colchicine has disadvantage of high poisonousness. It is necessary to find some non-toxic or low toxic substitutes that should have the same effect as colchicine. In this study, two anti-microtubule herbicides, amiprophosmethyl (AMP) and Oryzalin, were used to double the haploids under different treatment conditions, and the doubling effects were compared with colchicine. The results showed that the highest doubling rate induced by APM is about 45% in the condition of 20 mu M 24h. We calculated the actual doubling rate (survival rate x double rate), 38.23%, 20.64%, and 19.4% are the highest actual doubling rates induced by APM, colchicine, and oryzalin, respectively. Although both APM and Oryzalin can induce maize haploid doubling, comparing with the actual doubling rate, APM is better than colchicine. In addition, soaking seed had been proved the best way to operate and obtain the highest doubling haploids in all conditions. As a low toxic mitotic inducer, APM is a good substitute of colchicine in doubling maize haploids, which is suitable for application in the DH-based breeding pipeline.