Pollination studies in large cardamom (Amomum subulatum Roxb.) of Sikkim Himalayan region of India

Pollination studies in large cardamom were carried out at the research farm of ICAR Sikkim Centre, Gangtok, Sikkim, India during 2009–2010 to assess the effectiveness and efficiency of pollinators. Polleniferous flowers (65,890 ± 11,346.5 pollen/anther) of large cardamom produce spherical, large (108.64 μm × 96.32 μm) and echinate pollen with high pollen/ovule ratio (585.2 ± 134.8). Native bumblebee (Bombus braviceps Smith.), a nectar forager, was identified as the most effective pollinator in terms of pollination potential index score (0.88), pollen removal (55.39%) and deposition rate (4.5%), pollination efficiency and pollen delivery mechanism whereas honey bee acted as a pollen robber. Flowers appeared to be generalized; however, functional specialization was exhibited indicating that only bumblebee is adaptable for pollination moreover, pollination mechanism was an indicative of “pollination syndrome”.

► Bombus braviceps Smith, a nectar forager, was identified as the most effective pollinator in terms of pollination potential index score, pollen deposition rate pollination efficiency and pollen delivery mechanism.
► Honey bee (Apis cerena) acted as a pollen robber.
► Flowers of large cardamom appear generalized; however, functional specialization was exhibited by making only bumble bee adaptable for pollination.
► In this study we conclude that native bumblebee (B. braviceps) is the most important pollinator for large cardamom.