An attempt of using of Scots pine (Pinus sylvestris L.) seed orchard for plus trees testing purposes
Mass plus trees testing may be made only by means of half-sibs family tests. Family orchards are composed of such half-sibs, situates exactly as in the experiments using the complete randomized design method with one-tree plots. In the commercial half-sibs seed orchards the following have been estimated: the breeding value of each of 142 half-sibs as well as half-sibs and individual heritability, phenotypic, genotypic and environmental correlations between height, dbh, stem volume and absolute form factor.
The conclusions resulting from the experiment are as follows. Family seed orchards may be at least partially used for progeny tests purposes, as well as to estimate the genotypic parameters of the trees (families, and provenances, if the families represent different provenances).
The disadvantage of the family seed orchard in the scope of progeny tests purposes is lack of standards to compare and different parental population for each progeny (if plus trees derive from different populations). Family effects may be compared only with a mean that results in selection of particularly valuable families, however there are no unequivocal bases to reject the least valuable. Pines originating from Bory Tucholskie are of such high individual heritability of height, dbh, volume and absolute form factor (0.27–0.31) that selection of these features is purposeful. Family heritability is higher (0.49–0.53) that means that the selection of elite trees (family selection) shall bring more beneficial effects than the selection of trees according to their phenotype (individual selection).
Genotypic correlation of volume and dbh and height shows that the selection focused on height and dbh is simultaneously the selection focused on volume. Genotypic correlation of volume and dbh is higher comparing to correlation of volume and height. No genotypic correlation of volume and dbh has been found that may suggest that these features are inherited independently.
The plus trees are registered in the national register under the following numbers: 3887, 230, 3965, 4984, 3849, 3793, 3868, 3765, 3797, 3855, 1187, 3759, 3850, 1478, 3869, 1485, 3784, 3794 and 3779 and are of significantly high breeding value. Due to young age of the examined progeny this assessment may not be considered final.
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