Study on phenology and morphological characteristics of some provenances of dalbergia tonkinensis prain in Vietnam
2014
Pham Quang Thu; Nguyen Minh Chi; Dao Ngoc Quang; Bernard Dell
Dalbergia tonkinensis Prain is a rare and precious species, with high economic value, and as the price of timber can be up to 18 billion VND/m 3, exploitation threatens eradication of this species. Average number of leaflets compound leaf is 12.1-15.8, in which the lowest is Lang Son provenance (12.1) and the highest is Hue provenance (original obtained from Laos) (15.8). The provenances in Northern Vietnam have reached a height of over 17 m, with a single stem of good form, and cracked white or light grey bark. The other provenances are lower in height, low-branched or multi-stemmed, and with smooth greyish- white bark. The stage of development from flower bud to the mature fruit usually lasts about 10 months (April to January next year). Flowering is earlier, fruit development is faster, and leaves abscise earlier in Hue, Gia Lai, Ninh Binh, Thanh Hoa and Nghe An provenances than Lang Son, Hung Yen, Ha Noi and Vinh Phuc provenances. There is a clear difference in fruit characteristics: Trees of Ninh Binh provenance have long and thick fruits, but trees in Gia Lai provenance have very big fruits. Fruit shells of Lang Son, Nghe An and Gia Lai provenances are often soft, and fruit shells of Thanh Hoa provenance are very soft. Seed of D. tonkinensis is usually yellowish brown, thin, and oval; however, the seed from Hue and Ninh Binh provenances is dark grey, thick, long and tapering. Weight of 1,000 seeds range from 80 g (Hue provenance) to 137.3 g (Gia Lai provenance). The percentage of high quality seeds of Lang Son, Ninh Binh and Hue provenances is quite low (33.2 to 51.1%), compared to other provenances such as Hung Yen, Gia Lai and Hanoi (over 81%)
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