GENETIC-VARIATION IN THE NATURAL POLLEN CLOUD OF PINUS-SYLVESTRIS - ASTUDY BASED ON PROGENY TESTING

Seeds from open pollination of individual female stroboli on different days in June 1990 in a coastal clone archive of Pinus sylvestris (L.) in northern Sweden (latitude 63-degrees 39' N) were used for a short- term progeny experiment to study differences over time in the genetic composition of the background pollen. Analysis of progeny growth and c old acclimatization in artificial whole-plant freezing tests suggested no genetic differences in the fertilizing pollen between pollination days. A clinal variation with the latitude of pollen origin was observ ed for reference progenies from fertilization with pollen of known geo graphical origin. Comparisons between open-pollinated progenies and re ference progenies indicate that the pollen cloud originated from appro ximately 1-degree latitude (based on height growth) or 1.5-degree lati tude (based on freezing injury) north of the pollination site.