The objective of this research was to study the genetic differences among provenances, grown under same environment. Analysis of variance (Table.3) show that there are highly significant differences between provenances growth during different period of times. A question frequently studied for provenance trail: the question is that which provenance performs best and why? The answer to this question for aspen provenances in Athabasca is MN provenance; the reason is that area of MN provenance has high genetic level of diversity. One of the main findings of the experiment is that MN provenance shows highest growth rate during higher temperature and lowest growth rate during lower temperature. It also indicates that MN growth is positive correlated with temperature, increase in temperature leads to increase in growth of MN provenance and decrease in temperature results into decrease in growth.
Table 3. Analysis of variance of provenances growth over 5 year
Another exciting result from this trail is that during wet climatic conditions, all the provenances perform better in growth but during dry and hot environmental condition, only MN and SK perform better in growth than other provenances. It shows that MN has higher genetic resistance to higher temperature than other provenances. Results also show that growth of MN provenance decline by decrease in temperature, but growth of ABf provenance rises by decrease in temperature, it reveals that MN provenance has lower genetic resistance to lower temperature, and ABf has higher genetic resistance to lower temperature (Table 4).
Table 4. analysis of variance of annual provenances growth
By comparing MN provenance growth with other provenances during 2003, 2004 and 2008, Tukey’s multiple comparisons of means shows that MN provenance shows highly significant difference with other provenances
(Table 5).
(Table 5).
Table 5. Tukey's multiple comparison of means of provenances growth during 2003,2004 and 2008.
Based on these results, MN provenance shows the best growth under dry and hot conditions than other provenances and can be used as a source for future plantation in western North America. Moreover, further research on genotype to environment interaction is needed to provide more information about genetics of MN provenance.