Induction and identification of tetraploids of pear plants (Pyrus bretschneideri and Pyrus betulaefolia)

Polyploid plants usually exhibit broader leaves, thicker stems, bigger flowers and fruits, dwarfing stature, as well improved biotic abiotic resistance. Therefore, increasing the polyploidy is one of most important strategies used in plant breeding. Here, we reported successful induction tetraploids two pear varieties, ‘duli’ (Pyrus betulaefolia), a wildtype for rootstocks grafting, ‘Xinli No.7′ bretschneideri), popular cultivated variety China. This was achieved by treating their seeds, shoot tips tissue cultured or field grown seedlings with colchicine pendimethalin using three different methods: impregnation, mixed culture smearing. The best condition seeds impregnating them 0.4% 24 h where mutation rate 2.0% no chimera found. For 0.2% 6.67% (48 h) 13.0% (24 were mutated. In addition, found that method mixing 1.0% while it 0.5% colchicine. smear method, ‘duli’, h. Subsequently, DNA content these putative polyploid estimated flow cytometry, confirming ploidy nature. Also, compared morphological differences between tetraploid diploid seedlings. Obviously, appeared to be dwarfed shorter internode length reduced number stems.