Geographic Variation of China Fir (Cunninghamia lanceolata (Lamb.) Hook) in Taiwan: Analysis of Provenance Division by Ecotype and by Province

Abstract

China fir shows significant geographic variation because it grows in a great diversity of ecological environments; it is subject to geographic and reproduction isolation; and it has been cultivated selectively and separately by many local farmers. In order to match provenances and planting sites for greater genetic gain, seed collection zones are to be delineated. Forest geneticists in mainland China have separated China-fir provenances into 9 ecotypes. Using growth and isozyme data obtained from 2 test plantations (Liukuei and Lienhuachih) we tested the effectiveness of such ecotype delineation. We found that the grouping of China-fir provenances into 9 ecotypes was most effective for the analysis of early growth at the Liukuei plantation. It was only moderately effective for analysis of later growth at the Lienhuachih plantation. The grouping of provenances was not useful for isozyme frequency or heterozygosity analysis. The different degrees of effectiveness may be possible because the construction of such ecotype classifications in China were based solely on early growth data; no isozyme data were used. Grouping provenances by ecotypes was superior to grouping by political provincial origins for early growth. On the other hand, provincial grouping seemed to be better than ecotype grouping for later growth. When the 2 best ecotypes or 2 best provinces were selected, provincial selection seemed to be able to yield a higher genetic gain than ecotype selection. However, the selection results and their rankings seemed to be more consistent in the ecotype division than in the provincial division.