In vitro induction and characterization of hexaploid Pennisetum × advena , an ornamental grass

Pennisetum × advena (purple fountain grass) is an ornamental grass with considerable commercial value. In vitro induction of hexaploids and evaluation of the morphological and anatomical traits in P . × advena were conducted in this study. Nine independent hexaploids were generated from calli, which was initiated from immature inflorescence tissue of triploid P . × advena , treated with 0.1% colchicine for 24 h. Their ploidy levels were first screened by flow cytometry and further identified by chromosome counting. Compared with the triploids, the hexaploids showed a significant delay in flowering, and reduction in plant height, the number of tillers and number of inflorescences per plant, leaf length and width, inflorescence diameter, and the number of florets per inflorescence, but an increase in floret fresh weight, and anther diameter and length. Pollen grains in the hexaploids were well developed, and their fertility was restored. The production of hexaploids of P . × advena by colchicine treatment, and assessment of their growth parameters and pollen fertility, provide important information for future breeding of P . × advena .