Polyploid Induction and Identification of Begonia × benariensis

Begonia × benariensis series varieties have high ornamental and economic value and are excellent varieties for large-area group planting in gardens and green areas. At present, the B. × benariensis series varieties grown in China rely on foreign imports, and the price of imported germplasm resources is expensive, which greatly increases the cost of flower enterprises. In view of this, B. × benariensis (2n = 2x = 34) was used as the material, the callus was treated with colchicine to induce polyploid plants, and the polyploid plants were subjected to morphology, DNA content identification, and stomatal identification, as well as comparisons of the morphophysiological indexes of the plants. The results showed that the polyploid was better induced with the treatment of 0.05% colchicine for 4 h, and the induction rate was 46.67%. Among the mutagenized plants, there were 42 triploids (2n = 3x = 51) and 98 tetraploids (2n = 4x = 68). The stomatal density of diploid leaves was about 1.09 times that of the triploid and 1.67 times that of the tetraploid, the defense cells of the leaves increased gradually, and the stomatal density decreased; with the increase in ploidy, the height of the plants increased, while the crown width decreased; the maximum length and width of the leaves decreased, the color of the leaves became darker, and the chlorophyll content increased. This study provides abundant variation materials and technical support for the selection and breeding of new varieties of B. × benariensis in the future.