Open access publications in the SLU publication database

Abstract

The female and male flowering frequency were studied in a clone trial of Picea abies at Röskär nine kilometers north-east of Stockholm. During 1971 the extension in time of pollen shedding and female receptivity was recorded following daily examination of individual strobili. The data obtained revealed a great variation in female as well as male flowering between the clones. Only a part of this variation could be attributed to differences in height of the clones. Great yearly variations in flowering of individual grafts were noticed. Based on the flowering frequency as well as the pollen shedding and female receptivity during each day, the expected contribution of the different clones to the offspring was calculated. According to the calculations four of the clones contributed 55 per cent of the genes to the offspring. Many (66) of the 190 theoretically possible combinations among the 20 clones occurred in a lower frequency than 0.1 per cent. The consequences of the data obtained for the genetic composition of the seed orchard progeny were discussed.