| Catharanthus roseus is one of the most popular herbal ornamental species in China, and it is also a highly valued medicinal plant containing over 100 pharmaceutically important terpenoid indole alkaloids such as vindoline, catharanthine and vinblastine. Currently, there are few reports about C. roseus resources, its contained alkaloids content as well as the correlation between agronomic traits and alkaloids content. To investigate the agronomic traits of different C. roseus varieties and their correlations with the important alkaloids content is important for introduction and breeding of high alkaloids-content C. roseus varieties.In this study, the main agronomic traits (plant height, internodal distance, stem diameter, the first lateral branch number, leaf length, leaf width, leaf length/width ratio, one-hundred-leaf weight, whole plant leaf weight, petal diameter, seed pod length, seed number/pod and flower color) of 24 major C. roseus varieties currently grown worldwide, including China Hainan variety, Pacifica series varieties, Mediterranean series varieties, Cooler series varieties, HeatWave series varieties, SunStorm series varieties and Kirin Titan series varieties, and their correlations with the contents of important alkaloids including diterpene indole alkaloid vinblastine and monoterpene indole alkaloids vindoline and catharanthine were investigated. The major results are as follows:1. Significant difference existed in agronomic traits among different C. roseus species. China Hainan variety was superior to other varieties in most agronomic traits while European and American varieties (Pacifica series varieties, Mediterranean series varieties, Cooler series varieties, HeatWave series varieties, SunStorm series varieties) had abundant flower color, more branches and shorter plant height. Therefore, different varieties could be chosen as breeding materials with different breeding goals.2. The contents of 3 important alkaloids including vindoline, catharanthine and vinblastine were significantly different among different varieties. Vindoline content was the highest in HeatWave variety Mix Color (HWMC), reaching 2.34μg mg-1DW (leaf dry weight) (about 2.34‰DW), followed by China Hainan variety (2.31μg mg-1DW) and the lowest in HeatWave variety Pink (HWP) (0.26μg mg-1DW, about 0.26‰DW). Catharanthine content was the highest in Pacifica variety Polka Dot (PPD), reaching 3.79μg mg-1DW (about 3.79‰DW), followed by Mediterranean variety Rose Red (MRR) (3.52μg mg-1DW) and the lowest in Cooler variety Pink (CP) (0.9μg mg-1DW, about 0.9‰DW). Vinblastine content was the highest in Pacifica variety Cherry Red (PCR), reaching 0.51μg mg-1DW (about 0.51‰DW), and the lowest in HeatWave variety Pink (HWP) (0.03μg mg-1 DW). In C. roseus, vinblastine content was much lower than vindoline and catharanthine contents.3. The SPSS statistic software (version 13.0) was used in the correlation and path analyses of agronomic traits and the 3 alkaloids contents of different C. roseus varieties. The results showed that different agronomic traits had different correlations with the alkaloids contents. The correlation of vindoline content with the first lateral branch number and stem diameter reached the significant level (P<0.05), and near significant level with internodal distance. Path analysis indicated that among all the agronomic traits, the positive influence of internodal distance, the first lateral branch number and whole plant leaf weight on vindoline content reached the significant level (P<0.05). Internodal distance significantly influenced positively catharanthine content (P<0.05), while the first lateral branch number and petal diameter positively affected significantly vinblastine content (P<0.05). In addition, flower color was also found to have certain correlations with alkaloids contents, and the contents of all the three important alkaloids (vindoline, catharanthine, vinblastine) in deep color flower C. roseus varieties were high. This study indicates that agronomic traits could be used as the reference for the breeding of high-alkaloids content C. roseus varieties.The current study provides useful information for the introduction and breeding of high-alkaloids content C. roseus varieties.
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