Reproductive barriers to hybridizations between narrow-leaf and broad-leaf Anoectochilus roxburghii

ABSTRACT

Narrow-leaf and broad-leaf Anoectochilus roxburghii were used as reciprocal parents to explore the reason for low seed setting rate. Pollen-pistil interaction was observed by fluorescence microscopy and hybrid embryo development by paraffin section technology. The results indicated that pollen tube growth could reach the embryo sac, and double fertilization could be completed. These findings showed that a pre-fertilization barrier was not the major factor in the cross of narrow-leaf and broad-leaf A. roxburghii. The endosperm development of the hybrid was abnormal and eventually promoted abortion of the embryos. A post-fertilization barrier appears to be the major factor for low seed setting rate in the cross of narrow-leaf and broad-leaf A. roxburghii. In addition, an efficient protocol of embryo rescue, the development of which is reported elsewhere, was used to compare the time needed for rescue between the reciprocal crosses.

KEYWORDS:

• Anoectochilus roxburghii
• hybridization
• pollen-pistil interaction
• hybrid embryo development

Acknowledgements

We thank the anonymous reviewers for carefully reviewing our manuscript and making many valuable suggestions.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This work was supported by the National Natural Science Foundation of China [grant numbers 81303167; 81673531], and major science and technology projects of breeding new varieties of agriculture in Zhejiang province.