Breeding Polyploid Varieties of Acacia: Reproductive and Early Growth Characteristics of the Allotetraploid Hybrid (Acacia mangium × A. auriculiformis) in Comparison with Diploid Progenitors

Diploid clones of the hybrid acacia (Acacia mangium × A. auriculiformis) are widely planted in Vietnam because their high productivity, adaptability, and commercial wood yields. Polyploid breeding offers possibilities for further enhancing vigor generating new value genotypes. In a field trial, we compared three diploid with respective colchicine-induced tetraploid lines. Flowering seed production each cytotype were observed open pollinated collected determination outcrossing rate ploidy, inbreeding depression marker inheritance progeny. Comparisons also made published characteristics autotetraploids derived from mangium. Compared corresponding cytotypes, allotetraploids flowered slightly later but more intensely; produced same number seeds per pod larger seeds; showed greatly reduced level (an average 14% 87%). Inbreeding height growth was less progeny allotetraploid lines (17%) than those original diploids (33%). 96% tetraploid, triploids at low frequency both stages. The segregation molecular markers outcrossed progenies demonstrated disomic tetrasomic inheritance, indicating that behaves as segmental allotetraploid. Results suggest an strategy is practical option improving polyploid hybrids.