Objective To investigate the variations in morphology and sowing quality of Dalbergia tonkinensis seeds, and provide a basis for elite germplasm selection and further genetic improvement.

Method Morphology and germination of D. tonkinensis seeds of 47 families collected from 10 provenances in Vietnam were studied.

Result Seed length ranged from 10.22 mm to 15.43 mm, seed width ranged from 5.76 mm to 8.56 mm, seed thickness ranged from 1.59 mm to 2.56 mm and 1 000-seed mass ranged from 64.90 g to 153.73 g. The seeds from Gia Lai provenance had the highest germination rate of 72.6%, followed by those from Bắc Ninh of 69.4% germination rate, and the seeds from Huế had the lowest germination rate of 30.0%. Analysis of variance revealed that seed length, seed width, 1 000-seed mass, germination potential and germination index had highly significant differences (P<0.01) among provenances. Seed germination rate and seed thickness/width ratio had significant differences (P<0.05) among provenances. Seed thickness and seed length/width ratio had the lowest differences among provenances. There were also significant differences in seed length, seed width, and seed thickness among different families within individual provenances. The variability in 1 000-seed mass among provenances which ranged from 72.410 g to 139.671 g was much higher than the variability in 1 000-seed mass among families within individual provenances which ranged from 76.77 g to 118.11 g. Seed germination rate had highly significant positive correlation with 1 000-seed mass and seed width. Seed length, seed width and 1 000-seed mass had highly significant positive correlation with altitude and hours of sunshine. Cluster analysis indicated that the production areas of D. tonkinensis could be divided into three major regions.

Conclusion Seed size and seed proportion are the key factors affecting seed germination. Three major production regions of D. tonkinensis can be divided in Vietnam.