Pollen competition between cultivated and wild rice species (Oryza sativa and O. rufipogon)

Authors

  • Zhiping Song,

    1. School of Life Sciences, Wuhan University, Wuhan 430072, China;
    Search for more papers by this author
  • Baorong Lu,

    1. Ministry of Education Key Laboratory for Biodiversity Science and Ecological Engineering, Institute of Biodiversity Science, Fudan University, Shanghai 200433, China
    Search for more papers by this author
  • Yingguo Zhu,

    1. School of Life Sciences, Wuhan University, Wuhan 430072, China;
    Search for more papers by this author
  • Jiakuan Chen

    Corresponding author
    1. Ministry of Education Key Laboratory for Biodiversity Science and Ecological Engineering, Institute of Biodiversity Science, Fudan University, Shanghai 200433, China
      Author for correspondence: Jiakuan Chen Tel: +86 021 656 424 68 Fax: +86 021 656 424 68 Email: jkchen@fudan.edu.cn
    Search for more papers by this author

Author for correspondence: Jiakuan Chen Tel: +86 021 656 424 68 Fax: +86 021 656 424 68 Email: jkchen@fudan.edu.cn

Summary

  •  Post-pollination competition is reported here in cultivated rice (Oryza sativa) and a perennial wild rice (O. rufipogon) to investigate the occurrence of crop-to-wild gene flow.
  •  Wild and cultivated rice (variety Minghui-63) were grown in a common garden in Hunan province, China, and crop-specific genetic markers were used to detect hybridization following hand-pollinations. Using 11 sequential pollination treatments, the effects of the relative timing of pollination on the success of foreign pollen was investigated.
  •  Foreign pollen from the crop resulted in lower pollen germination, fewer pollen tubes per style, and a significant reduction of seed set, demonstrating a disadvantage of foreign pollen even in the absence of pollen competition. When 1 : 1 pollen mixtures were applied, only 2% of the resulting seeds were hybrids, revealing a much stronger disadvantage of foreign pollen when competing with conspecific pollen. Testing the effects of the relative timing of pollination on the success of foreign pollen suggested that conspecific pollen is often more successful than foreign pollen. Nonetheless, hybridization is possible following the deposition of pollen mixtures, especially when foreign pollen arrives earlier than conspecific pollen.
  •  Pollen competition between wild and cultivated rice could slow the rate of crop-to-wild gene flow, but even if pollen competition was ubiquitous it would not prevent gene flow from the crop.

Ancillary