Asian Program

Japanese

Data

Former Fellows

Dissertation Abstracts

Thailand

  In this thesis, I describe various aspects of reproductive biology, diversity and abundance of canopy insects, pollinators and their behaviors in natural (wild, W) and plantation (clonal seed orchards, CSO) forests. The research relates these areas to the breeding system of teak.
  The number of morphospecies of pollinators in the plantation canopy (59) is higher than that in the natural canopies (51). The plant produces many inflorescences with a large number of flowers and pollen grains but produces mature few fruits. Teak is weakly protandrous but this is an inefficient mechanism to prevent selfing. Teak flowers can be easily self-pollinated by many pollinators found in the canopy. This results in a lack of cross-pollination causing a high rate of fruit abortion. Based on the number of insect visits and their contribution to the flowers being pollinated, two bee species, Ceratina sp. and Trigona collina were the major pollinators at Saraburi plantation and at the Phayao seed orchard, respectively. Self-incompatibility mechanisms are responsible for pollen-tube growth inhibition in the self-pollinated ovaries (GSI). The index of self-incompatibility, which indicated that teak is mostly self-incompatible, explains the capability and difficulties in setting fruit by self-pollinations.
  These results indicate that the low natural fruit set of teak predominantly relates to pollinator species and their foraging behavior. Large pollinators, i.e. Nomia sp., A. cerana show a high foraging rate, low ratio of visits within the same inflorescence, and an approach to flowers from the top. These behaviors benefit pollination of teak which is an outcrossing species. Based on these findings, I suggest some future work to ensure the quality of improved seeds in seed orchards.