Polyploid induction of <i>Luculia pinceana</i> Hook. by aseptic germination combined with chemical agents

Summary To obtain polyploid Luculia pinceana Hook., chemical mutagenesis, tissue culturing and rapid propagation technology were used, and the resulting germplasm may be bred to produce new varieties. The seeds of L. pinceana were used as induction materials, soaked in different oryzalin and colchicine concentrations, and then, mutant plants were obtained through seed germination. The variation rate of the plants was calculated on the basis of hypocotyl enlargement. Morphological characterization, stomatal characteristics, chromosome counts, and flow cytometry were used to identify mutant plants. The seeds soaked in 0.6% colchicine for 48 h had the best induction effect, and the mutation rate reached more than 70%. The chromosome count determined that the diploid chromosome number of L. pinceana was 2 n = 2 x = 44 and the tetraploid chromosome number was 2 n = 4 x = 88. In total, 11 tetraploid strains were identified by chromosome count and seven were identified by flow cytometry. Tetraploid plants had a dwarfed phenotype, with round leaves and thick roots, and a low density of large stomatal guard cells. In this study, a new polyploid L. pinceana germplasm was obtained for the first time, and it provided intermediate materials and a scientific basis for the breeding of new varieties.