QUANTITATIVE GENETIC-VARIATION AND GENOTYPE BY ENVIRONMENT INTERACTION OF EMBRYO DEVELOPMENT RATE IN PINK SALMON (ONCORHYNCHUS-GORBUSCHA)

Quantitative genetic variation of development rate was evident among 2 0 half-sib and 40 full-sib families within each of two seasonally sepa rate components of a population of pink salmon (Oncorhynchus gorbuscha ) (H-o: no sire effect on temperature units at hatch, P < 0.02). Diffe rences between averages of families spawned 3 weeks apart may have had genetic or environmental sources (e.g., in constant 8 degrees C, earl y embryos hatched at 606 temperature units, and late embryos, at 625). Statistical interactions between paternal effects and environment (em bryos were cultured in four temperature regimes, two simulated natural regimes and two constant temperatures; H-o: no sire by regime interac tion effect on temperature units at hatch, P < 0.09) were weak evidenc e that genotype by environment interactions contributed to variation. Paternal effects in analysis of variance (evidence of additive genetic variation) were detected only at later stages. Evidences of genetic v ariation and of interactions between genotypes and environments are pe rtinent to resource conservation because they suggest that harvest man agement or hatchery practice have the potential to reduce genetic vari ation in salmon populations.