Genome size variation and evolution in some species of Dalbergia Linn.f. (Fabaceae)

The present study deals with the extent of genome size variation and evolution in some species of Dalbergia. The interspecific 4C DNA content variation has been analyzed in 30 accessions belonging to ten species of Dalbergia. The 4C DNA content in ten Dalbergia species ranges from 5.85 pg in D. lanceolaria to 7.88 pg in D. borrida, about 1.3 fold variation is apparent at a constant chromosome number 2n=2x=20. ANOVA test reveals significant variation between species. Like other woody angiospermic taxa, tree species of Dalbergia exhibit small genome size ranging from 5.85 pg in D. lanceolaria to 7.22 pg in D. sissoides. In contrast, the shrubs and climbers of this genus also reveal a narrow range of genome size variation from 7.36 pg in D. rubiginosa to 7.88 pg in D. horrida The climber species of this genus exhibits higher DNA amount than the tree species. The present investigation indicate that lianas or climber species of Dalbergia have evolved from tree species through evolutionary increase in genome size. The extent of DNA amount differences between the Dalbergia species has been discussed in the light of their interrelationships and diversity.