Effect of maternal soil treatment on first year growth and autumn frost hardiness of Pinus sylvestris L. full‐sib families

Abstract

After‐effects of maternal soil treatment, controlling for photoperiod and weather conditions, were tested in a nursery experiment with Pinus sylvestris L. seedlings. Three full‐sib crosses were replicated in 4 different soil treatment plots of a grafted experimental seed orchard (63"54'N). Weight of filled seeds, percentage of empty seeds, first year hypocotyl and epicotyl length, and autumn frost hardiness (from artificial freeze testing) were evaluated. Systematic effects from maternal soil treatment were small compared to family differences for all characters studied. However, epicotyl length of the progenies showed a positive relationship with N needle content of the mother grafts. The results also indicated an important interaction between maternal soil treatment and autumn frost hardiness of the families. It is suggested that the altered mother tree treatment could lead to a change in progeny performance, corresponding to a 1.5 degree difference in latitudinal origin of natural stand seedlings. The results demonstrate the advantages of providing the mother tree with uniform conditions in early progeny testing.

Key words:

• Pinus sylvestris
• after‐effects
• environmental preconditioning
• maternal environment
• full‐sib families
• freeze testing
• early testing