Induced Autotetraploids in Salvia miltiorrhiza and Their Agronomic Traits

Salvia miltiorrhiza is an important medicinal plant for its special pharmacological activity in cardiovascular and cerebrovascular diseases. The objective of this work was to develop S. miltiorrhiza autotetraploid through colchicine and to reveal their agronomic traits. For polyploidy induction of S. miltiorrhiza, seedlings at the shoot apexes stage were treated with colchicine in various concentrations [0, 0.1%, 0.2%, and 0.3% (w/v)] in three treated times (3, 5, and 7 applications). Putative autotetraploid were selected by morphological and stomatal characteristics, and their ploidy level was confirmed by flow cytometry analysis and chromosome counting. As expected, the chromosome number was 2n=2x=16 in diploids, and 2n= 4x= 32 in the autotetraploid. According to the results, 0.2% (w/v) of colchicine treatment 6 times can be effective for polyploidy induction in S. miltiorrhiza. The autotetraploid plants usually were accompanied by larger leaf size, stoma size, and pollen grains, but a decrease in the percentage of normal pollen. Since some autotetraploid plants showed morphological and physiological traits, antioxidant enzyme activity, wet weight, and bioactive compounds content superiorities compared to diploid plants, they can be used as germplasm materials for the breeding of S. miltiorrhiza.