Advances in the study of breeding system and pollination biology of gingers (Zingiberaceae and Costaceae)

Abstract

In this paper we presented a review of the advances in the studies of breeding system and pollination biology of gingers. The Zingiberaceae is a large family of animal-pollinated pantropical monocotyledons with more than 1500 species in ca. 50 genera. There are many kinds of sexual variations occurring in the ginger family, such as gynodioecy, andromonoecy, flexistyly, protandry and self-incompatibility. Major pollinators include bees, hawkmoth, butterfly and birds, and different pollinators correspond with different morphological characteristics of flowers. Among the relatively few studies on the pollination biology, members of this family display some unique pollination mechanisms and breeding systems. Flexistyly, found in the genera of Amomum and Alpinia, is regarded as a unique behaviour mechanism that encourages outcrossing; a new self-pollination mechanism has been discovered in Caulokaempferia coenobialis, in which a film of pollen is transported from the anther by an oily emulsion that slides sideways along the flower’s style and into the individual’s own stigma. These studies and discoveries give us a better understanding on the diversity of pollination and breeding systems of gingers. For future research, we suggested that more studies should be carried out on the pollination and breeding systems of gingers in a wider range, and phylogenetic research should be conducted to understand the evolution of pollination and breeding system in Zingiberaceae, and for the flexistyly, more detailed studies should be done about this unique sexual polymorphism.