Abstract: Many instances of polyploid poplars indicate that it is probable to achieve multi-objective and integrated improvement of poplars and to produce varieties characterized by fast growth, long fiber length, low content in lignin, high content in fiber and strong adversity resistance through one round of polyploid breeding process based on sexual polyploidization. In practice of polyploid breeding of poplars, it is helpful for increasing the efficiency and effect of polyploid production to master the methods for instant determination of effective treating period of gametic and zygotic chromosome doubling. Furthermore, because phenotype of one polyploid is associated with its heterozygosity, it is important to select suitable parents, mating individuals and approaches for gametic chromosome doubling. Maximization of the heterozygosity in polyploids can carry out advantages of both ploidy vigor from gene dosage effects and heterosis from union of heterologous female and male gametes, leading to maximize the potential of techniques for polyploid breeding of poplars.