© 2004 by Institute of Chartered Foresters
The after-effects of reproductive environment in shortleaf pine
A1 USDA Forest Service, Southern Research Station, Southern Institute of Forest Genetics, 23332 Hwy 67, Saucier, MS 39574, USA A2 USDA Forest Service, NFGEL Laboratory, Placerville, CA, USA
Thirteen identical controlled crosses were made among 22 shortleaf pine (Pinus echinata Mill.) clones growing in two contrasting reproductive environments: a seed orchard in central Arkansas, USA (34.6°N) and a clone bank in south Mississippi (30.5°N). The resulting seedlings from both reproductive environments were planted at both locations where the seed was produced. After 4 years in the field (5 years from seed), trees from seed produced in the two environments differed significantly in height. The reproductive environment x family interaction was also significant, however, indicating that the effect depended upon the genetic background of the parent trees. By age 9 years, differences were no longer statistically significant. Allozymes were assayed in seed produced in the two reproductive environments. Chi-squared tests of heterogeneity of segregation ratios for polymorphic loci showed significant differences between the two environments for many cross/loci combinations. Although the pattern of differences was not obviously linked to differences in growth, gametophytic selection is suggested as a possible explanation for the after-effects.