Genetic parameters of 2‐year‐old full‐sib families of Pinus contorta and correlation with field test data

Abstract

Height increment among full‐sib families of lodgepole pine plus trees were assessed during different growth phases of the first and second year in nursery. The percentage of the total variance in seedling height and increment due to general combining ability was similar for all growth phases (4–6%). Specific combining ability was significant only at 5 weeks in year 1 (16.2%). Maternal effects were significant at 5 weeks both in year 1 (10.0%) and year 2 (2.5%). Total increment each year was not maternally influenced. The variance component of general combining ability and also the coefficient of variation for height were of a similar size among the corresponding half‐sib families in a 10‐year‐old field test, while the family ranking differed. Present results indicate that breeding should follow methods that make use of general combining ability.

Key words:

• Pinus contorta
• height growth
• general and specific combining ability
• maternal effects
• coefficient of variation
• progeny testing
• early testing
• growth rhythm