Abstract:

The two international provenance trials of Casuarina junghuhniana Miq. were established in Zhangzhou, Fujian Province and Dianbai, Guangdong Province in southern China. The 28 seedlots of seeds all came from Australian Tree Seed Centre, CSIRO. A complete randomized block design was employed for each site, with 16 or 25 trees per plot and 4 blocks or replicates. From 1 to 4 years old, tree height (H, m) and diameter at breast height (DBH, cm) were measured, calculated single tree volume (V) and tree survival percentage (S, %). The results showed that there were significant differences in all traits between sites, between provenances, and between interaction of provenance x site (G x E) , which indicated that those provenances were not only genetic variation in tree growth indexes at each site but also genotype x site interaction. Provenance broad heritability was calculated. Using H, DBH,V and S at 4 years, by the Multiple Objective Strategic Decision Analysis method, provenances in each trial was optimized and ranked. On the purpose of high wood yield in plantation, the selected provenance rate was 25% of the total seedlots in the trials. Then the 7 seedlots 19238, 18847, 18853, 17877,18950,18852 and18949 at Zhangzhou (E 966), and the 7 seedlots 18844, 19489, 19240, 17877, 19491, 19490 and 19239 at Dianbai (E 968), were screened out as better provenances. These seedlot comprehensive estimating index values (Wi) were significantly bigger than the mean value of the whole seedlots. Genetic variation coefficients and broad-sense heritability (H²) of provenance in all traits were estimated from 1 to 4 years after planting. The early age-age phenotypic/genetic correlation coefficients of tree heights from 1 to 4 years old, and between H, DBH, V and S traits were all.significant positive, which could be benefited to the early age-age prediction for tree height, or indirect selection and comprehensive selection for provenance. Possible suitable areas of Casuarina junghuhniana provenances were predicted in southern China, by means of Booth's model.

Key words: Casuarina junghuhniana, Provenance trial, Genetic variation parameter, Selection, Southern China