The study of conservation and recreation in K. davidiana var. formosana

Keteleeria davidiana var. formosana are indigenous trees only in the northern and southern parts of Taiwan. These trees had already been listed as one of conservative tree species and protected by the government due to their scarce population and low ratio of seed setting. These trees numbered less than 400. Moreover, their vigor is decreasing coupled with few regeneration offsprings in nature stands for their low quality of seed production- more than 97% seeds per cone is empty. Cone and seed development was observed from 1993 to 1998 in wind-pollinated K. davidiana var. formosana trees grown at Taipei Botanical Garden. Seed efficiencies per cone were persistently less than 1% during the investigation period. Sections of large seeds at different stages during the period from polyembryos to cotyledonary embryos revealed that 80% of them were successfully fertilized initially, and then almost all degenerated before developing into mature embryos. We plan to pollinate between the northern and southern provenances to determine the effect of imbreeding on the embryo aborting in this project and to broaden the genetic base of K. davidiana var. formosana. The grafts derived from two provenances have been established several years ago in TFRI. However, they have not flowered yet until now. Since GA4/7 has been proved to be effective to promote flowering in Pinaceae, we will apply GA4/7 on these grafts to induce flower buds. Controlled pollination will be conducted in these grafts, in stead of a difficult job doing in the giant trees. Seed efficiency and their offspring will be investigated.