NURSERY SELECTION OF PICEA-ABIES CLONES AND EFFECTS IN-FIELD TRIALS

The effects of early selection of clones in the nursery on field perfo rmance after 6 yrs in the field were studied in a material comprising 794 cutting propagated clones of Picea abies (L.) Karst. A 20% selecti on for height in the nursery gave gains of approximately 3% in height after 6 yrs. Attempts to improve the early selection procedure were ma de. Stratification of the nursery beds in two blocks according to loca tion had almost no effect on the gain, and selection within growth rhy thm classes was less effective. Correlations between other characters measured in the nursery and field characters were generally low. The p ositive, though moderate, relationships between nursery height and hei ght after 6 yrs in the field are encouraging for further research to i mprove selection efficiency.