Population genetics in a pilot project on intraspecific crossing of the silver fir (Abies alba Mill.) in Saxony
1996
Llamasgomez, L.
The conservation of the residual populations of Silver fir (Abies alba MILL.) in Saxony requires activities to get over the isolation e.g. controlled crossings. In 1994; the Saxon State Institute for Forestry began first experiments to pollinate isolated Silver fir trees by controlled crossing. Isolated macrostrobili mere pollinated with pollen from 6 single trees and a pollen mixture from 4 of them simultaniously with controlled selfing. The pollen mixture was also applicated to macrostrobili without isolation. Seeds sired by the controlled selfing showed a lower proportion of filled seeds than by outcrossed combinations. Nevertheless, a relatively high self- fertility of Silver fir has been observed. The genotyps of the parent trees and their offsprings, based on 10 gene loci, were determinated by means of isozyme analysis. Segregation distortion was not found in any of the single combinations. 35% of the progenies sired by selfing and free pollination were not heterozygous at any locus. 65% of these progenies were heterozygous at only 1 locus. Progenies derived from pollination with the pollen mixture showed 85% of heterozygous embryos at 2 or more gene loci. The parental analysis indicates no differences between the progenies from selfing and free pollination. The proportion of seeds sired by each of the male parents in the polycross mixture differs from the expected value. It was found that gametes which produce a low proportion of filled seeds in certain combinations may have a selection advantage in the pollen mixture. The additional pollination of macrostrobili without isolation contributed to 85 % of the progenies at least.
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