Clonal propagation and genetic testing of Virginia pine (Pinus virginiana Mill.)

The purpose of this research was to investigate the potential for incorporating clonal propagation into the Virginia pine Christmas tree improvement program. Information was needed on how tissue culture plantlets performed in the field. Field trials were established to test field performance of plantlets relative to seedlings; and to test for genotype-by-environment (GxE) interactions and stability in plantlets, seedlings and individual clones. Plantlets and seedlings from two genetic sources were tested.; Plantlets appeared comparable to seedlings for survival, except for a higher rate of mortality during the establishment phase of one of the field trials, which was possibly due to drought stress. Plantlets were significantly smaller than seedlings in two of the three field performance trials, but these differences were largely confined to only one of the genetic sources tested. There were no significant differences in plant types for relative height growth (RGR).; GxE interactions, due to different locations or different years, were not significant for plantlets or seedlings, indicating that the additive genotype-by-environment (AxE) component was not critical. Stability of plantlets and seedlings for RGR was relatively comparable, and stability for survival was mixed, depending on the genetic source. GxE interaction was significant at the clonal level, for both survival and RGR, indicating the importance of the non-additive genotype-by-environment (NAxE) component.