Open access publications in the SLU publication database

Abstract

The purpose of the present investigation was to compare the megasporogenesis in a clone of Norway spruce with an ordinary seed set and a clone of a reduced seed set. The early prophase I stages had the same appearance in both clones. During the last part of diplotene there was a separation of the bivalents (i.e. desynapsis occurred) in the clone with the reduced seed set. During metaphase I-anaphase I 97 per cent of the embryo sac mother cells from the desynaptic clone contained at least one univalent. As a consequence of the occurrence of univalents micronuclei and other irregularities were observed during subsequent stages. Frequently the irregularities caused a degeneration of the cells. Thus, it was proved that the desynapsis was responsible for the poor seed set in the desynaptic clone of Norway spruce.