Abstract

Bell flower (Platycodon grandiflorum (Jacq.) A. DC.) has been widely cultivated for medicinal, edible and ornamental purposes. In this study, a stable male-sterile line, GP1BC1-12, was developed based on the discovery of original male-sterile plants of bell flower from cultivated populations in 2004. And three hybrid cultivars, “Zhonggeng No. 1”, “Zhonggeng No. 2” and “Zhonggeng No. 3”, were further bred using GP1BC1-12 as female parent in producing hybrids seeds. Deduced from the assay of crosses between GP1BC1-12 and 18 self-cross lines, GP1BC1-12 belonged to the nucleo-cytoplasmic interaction type of male sterility and its maintainers exited extensively. Over-standard heterosis of the hybrids was common and evident, and average over-standard heterosis in the weight of root, the weight of main root per plant and the rate of taproot was 47.50, 44.33 and 25.45%, respectively. The strain comparison and regional yield trials of three hybrid cultivars were conducted. The results showed that the hybrids had higher yields than the mainly cultivated populations in China. This is the first report about the development of a stable male-sterile line and the breeding of new hybrid cultivars for bell flower. It can be predicted that the extension and utilization of the new hybrid cultivars with high yield and high disease resistance will benefit the growers of bell flower. Moreover, the consistent genetic background of hybrid cultivars will contribute to the quality control of medicinal materials.

Key words: Platycodon grandiflorum (Jacq.) A. DC., male-sterile line, cytoplasmic male sterility (CMS), heterosis, hybrid cultivar.