Abstracts

Up to now, the formation of forest-seed base of the main foresting species in Russia is based on using plus trees. However, an attitude to the efficiency of plus selection is different. It has been noted that a genetic effect as to growth rate on forest-seed orchards of the 1st order is 8-9% and even may reach up to 25%. At the same time, some researchers point out a low efficiency of plus selection due to an insignificant part (1-10%) of fast-growing trees. As a result, on forest-seed orchards of the 1st order formed by untested plus trees, the effect of character improvement may appear to be low. To our mind, one of the causes of nonuniformity of plus trees is objectivism of researchers (valuers). Moreover, when under mountain conditions, an environmental factor may have a great effect on the quality of plus trees bred for gross productivity. Mapping of soil thickness under trees on rocky bottom has shown that it varies from 10 cm to a few meters, thus having a substantial effect on soil nutrition conditions. The preliminary quality check of Siberian-cedar plus trees for gross productivity and tree trunk quality (taken from mid-mountain subbelt of forest belt in the North-Eastern Altai taiga), selected by the adopted selection criteria of height and diameter, has been carried out for three years in a production greenhouse of the former Mountain Altai experimental timber-industrial complex enterprise. The families from 53 plus trees have been tested, with comparison plantings made in three replications. An estimate was made within each replication, with mean values of seedlings height used as a check. In view of natural perishing and partial usage of seedlings for production needs, we have tested, from the remaining plantings, 44, 36 and 38 families in the 1st, 2nd and 3rd replications, respectively. By using a coefficient of variation, we have revealed a pronounced variation in families height, which amounted to 36%, 18.8% and 29.9% in the 1st, 2nd and 3rd replications, respectively. Intrafamily variation turned out to be higher, i.e. 41% in the 1st replication, whereas 34% in the 2nd and 3rd replications. Vigor growth was evidently observed: in the 1st replication – 5 of 44 families (13%), in the 2nd replication – 5 of 38 families (14%), in the 3rd replication – 4 of 38 families (10.5%). Poor growth was evidently observed: in the 1st, 2nd and 3rd replications – 18%, 11% and 13%, respectively. The analysis of seedling growth dynamics in families for years has shown synchronism and sufficient stability of rank in the majority of families to be tested during the first three years. On the whole, it is evident that all plus trees are heterogeneous. Great interfamily and intrafamily variation makes it possible to select the best families and individual trees as to quality even at the stage of preliminary test.

Note. Abstracts are published in author's edition

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