Research on ploidy identification and characterization of acacia mangium tetrapolids in comparision with diploid clones in Vietnam
2009
Le Dinh Nha, R. Giriffin, Ha Huy Thinh, J. Harbard; Le Son; Duong Thanh Hoa; Nghiem Quynh Chi
Research on ploidy identification and characterization of Acacia manguium tetraploids in comparison with diploid clones introduced from Australia and selected diploids from Vietnam have been conducted in laboratory and field trials at Ba Vi (Ha Noi), DongHa (Quang Tri) and Bau Bang (Binh Duong). The specific characteristics of diploid and tetraploid clones as ploidy index, stomatal cell's relative pollen lump have been identified. The most of in vitro propagated clones derived from colchicine treated Acacia Manguium have been identified as tetraploids (4n), but some clones are diploid (2n). The ploidy identification by Flow Cytometry showed that the polyploid index of 4n forms is more than 180 while ploidy index of 2n is varied between 75 and 95. The stomatal cell's relative area of 4n is varied over the range 14,413 to 14,421 while of 2n is 8,480 to 9,030 units. The relative pollen lump volume of 4n is varied from 55,726 to 65,804 while of 2n is 30,730 to 32,764 units. The clones with exactly identified ploidy levels are that ones that have identified chromosome numbers or possessed all characteristics as ploidy index, stomatal cell's relative area and relative pollen lump volume, specially characterized for each ploidy level as above-mentioned. The stem volume of 4 years-old tetraploid Acacia manguium trees is varied from 7.03 to 67.22 dm3/tree, while of respective diploids is 20.2 to 99.99 dm3/ tree. Wood fiber length in stems and branches of 4n (644.5-695.4µ m) is not significantly different with that of 2n (600.8-626.6 µ m), while wood fiber diameters of 4n and 2n are signficantly different , 16.91-19.52 and 13.80-15.96 µ m respectively. The selected tetraploid clones will be used for triploid heterotic breeding program.
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