ABSTRACT
Polyploid breeding is one of the most effective approaches for improvement of poplars, as allotriploid poplar varieties exhibit good growth and wood quality properties. Several methods have been developed in poplars in order to produce allopolyploids efficiently, including hybridization with spontaneous 2n gametes, crossing with 2n pollen or eggs induced by colchicine or high temperature treatment, and chromosome doubling of zygotes or somatic cells. In the practice of polyploid poplar breeding, knowledge of reproductive biology characteristics is the key to improving chromosome doubling efficiency. Furthermore, utilization of both heterosis and vigor due to increased ploidy via sexual polyploidization is very important in poplar polyploid breeding. However, due to the normal segregation of trait phenotypes during sexual polyploidization of poplar, strong selection based on a large polyploid population is necessary for polyploid varieties.
