Genotype × environment interaction in Norway spruce involving three levels of genetic control: seed source, clone mixture, and clone

Abstract

A total of 913 Piceaabies (L.) Karst. clones was tested for height at ages 1 and 5 in two series on six and three locations, respectively, in Sweden. The genotype × environment interaction was studied for three levels of genetic control, i.e., seedling checklot, clone mixture, and clone. Stability of all three was estimated using regression coefficients. The alternative method, genetic correlation between locations, was also used to measure stability. Height differences among seedling checklots and among clones were substantial at age 5, while the variation among clone mixtures was not significant. Genotype × environment interaction was found to be significant for clones and accounted for an average of 2.1% of the total variance at age 5. No significant interaction was found between mixtures and locations. The genotype × environment interaction for seedling checklots was not significant and accounted for 0.5% of the total variation at age 5. The stability of seedling checklots at age 5 was high. For the clone mixtures, stability was found to be about average. Individual clones showed wide variation in stability. There was an apparent negative relationship between clone performance and stability. Genetic correlations indicated close agreement between locations in the ranking of clones for height growth.