J Syst Evol ›› 2022, Vol. 60 ›› Issue (6): 1281-1290.DOI: 10.1111/jse.12810

• Research Articles • Previous Articles     Next Articles

Natural interploidy hybridization among the key taxa involved in the origin of horticultural chrysanthemums

Shuai Qi1,2, Alex D. Twyford3,4, Jun-Yi Ding1,2, James S. Borrell5, Long-Zhen Wang1,2, Yue-Ping Ma6, and Nian Wang1,2,7*   

  1. 1 State Forestry and Grassland Administration Key Laboratory of Silviculture in Downstream Areas of the Yellow River, College of Forestry, Shandong Agricultural University, Tai'an 271018, Shandong, China
    2 Mountain Tai Forest Ecosystem Research Station of State Forestry and Grassland Administration, College of Forestry, Shandong Agricultural University, Tai'an 271018, Shandong, China
    3 Institute of Evolutionary Biology, Ashworth Laboratories, University of Edinburgh, Edinburgh EH9 3FL, UK
    4 Royal Botanic Garden Edinburgh, Edinburgh EH3 5LR, UK
    5 Royal Botanic Gardens Kew, Richmond TW9 3AB, UK
    6 College of Life and Health Sciences, Northeastern University, Shenyang 110004, China
    7 State Key Laboratory of Crop Biology, Shandong Agricultural University, Tai'an 271018, Shandong, China

    *Author for correspondence. E‐mail: nian.wang@sdau.edu.cn
  • Received:2021-05-26 Accepted:2021-07-30 Online:2021-08-18 Published:2022-11-01


Understanding hybridization and introgression between natural plant populations can give important insights into the origins of cultivated species. Recent studies suggest differences in ploidy might not create such strong reproductive barriers as once thought, and thus studies into cultivated origins should examine all co-occurring taxa, including those with contrasting ploidy levels. Here, we characterized hybridization between Chrysanthemum indicum L., Chrysanthemum vestitum (Hemsley) Ling and Chrysanthemum vestitum var. latifolium (Zhou & Chen), the most important wild species involved in the origins of cultivated chrysanthemums. We analyzed the population structure of 317 Chrysanthemum accessions based on 13 microsatellite markers and sequenced chloroplast trnL-trnF for a subset of 103 Chrysanthemum accessions. We identified three distinct genetic clusters, corresponding to the three taxa. We detected 20 hybrids between species of different ploidy levels, of which 19 were between C. indicum (4x) and C. vestitum (6x) and one was between C. indicum and C. vestitum var. latifolium (6x). Fourteen hybrids between C. indicum and C. vestitum were from one of the five study sites. Chrysanthemum vestitum and C. vestitum var. latifolium share only one chloroplast haplotype. The substantially different number of hybrids between hybridizing species was likely due to different levels of reproductive isolation coupled with environmental selection against hybrids. In addition, human activities could play a role in the different patterns of hybridization among populations.

Key words: Chrysanthemum, hybrid, microsatellite marker, symmetrical introgression, trnL-trnF