Epsilon Open Archive

Abstract

Some applications of the isozyme technique for studies in seed orchards are discussed. The basis for these studies is the opportunity to use clones in the seed orchard which are isozymetically distinct from the others. If a clone ill one locus carries one or two alleles unique or rare to the orchard, it may then be possible to trace the contribution of this particular clone to the seed formation. The use of this method in studies on the net effect of open pollination in a seed orchard is pointed out. In the absence of such unique alleles for tile estimation of the pollination situation, another method is suggested. This method cart be made use of by collecting open-pollinated seeds from a clone and counting plants from these which, by means of the isozyme pattern, show a documented cross-pollination. In this way it is possible to obtain information on the occurrence of selfing. Checking of the isolation technique for controlled crosses is also possible with this isozyme technique. The theoretical opportunities for future studies of correlations between economically important traits and allozymes (allelic isozymes) are discussed briefly. The theoretical possibilities are partly illustrated by results obtained from Swedish Scots pine seed orchards. No indication of deviation from random mating were found. The frequency of plants originating from selfing following open pollination was indicated to be in the range of 2-5 per cent. Such plants seemed to be more common in the lower than in the upper part of the crowns of the ramets. The relevance of checking controlled crosses is demonstrated by means of an applied example.