Performance of Acacia auriculiformis in second-generation progeny trials in Thailand

Two progeny trials of Acacia auriculiformis were established using open-pollinated seed from selected trees in first-generation seedling seed orchards. In total there were 106 families of which 13 came from three original Thai land races, 47 from four original Papua New Guinea provenances, 25 from six original Queensland provenances and 21 from seven original Northern Territory provenances. In addition, two local unimproved seed trees were included. Height and diameter assessed 24 months after planting confirmed the very poor growth rate of all Thai selections compared with families from Papua New Guinea and from Queensland and Northern Territory, Australia. Families from the Queensland provenance region were generally more productive than their counterparts from Papua New Guinea and Northern Territory. On the basis of these results it is proposed to focus on selected genetic material from Australia and Papua New Guinea for the improvement program of this species in Thailand.