The results of long-term study of vegetatively propagated apple rootstocks in the mother tree of vertical layering in the conditions of forest-steppe zone of the Southern Urals

The research objective was to give an assessment to new forms of dwarf clonal stocks of an apple-tree in stool-bed of vertical layers in the conditions of a forest-steppe zone of South Ural on a complex of signs and to allocate the most adaptive. The research problems were the assessment of the indicators of winter hardiness, drought resistance, the efficiency of mothering bushes and rooting of the layers. Under the conditions of the Middle Volga region, dwarf rootstocks Ural 1, Volga 3, semi-dwarf Ural 5, Ural 2, Ural 6, Volga 12 from open pollination of stocks of the Michurinsk SAU selection were studied. They are characterized by increased frost resistance of their root system, drought tolerance, and a high reproduction rate - over 100 thousand/hectares of liners, high yield of nursery trees in the nursery (up to 80-85 %) and productivity in the garden was 1.5-2 times higher than in the etalon (54-118, 62-396). A group of rootstocks and elite forms, most adapted to the conditions of the forest-steppe zone of the Southern Urals, were selected from the collection of clonal rootstocks in the stool-bed. The highest yield of stocks from a bush was up to 10-15 units in forms 64-143, Arm 18, Ural 2, Volga 12, elite forms P-8-8, S57-490 V, 19-10, 19-7, OB 3-4, OB 2-15, OB 3-14. Theleast number of layering was obtained in units 6-8 from the bush of SPS-7, 62-223, 4-5. The yield of liners was obtained up to 150 thousand / hectare and more for forms 64-143, Arm 18, SPS-7A, Volga 12, Volga 8,elite forms P8-8, s-c 57-490 V, 19-10, 19-7. Less than 100 thousand / hectare were in etalon 54-118 - 82.4 thousand / hectare. Rooting ability of stocks was higher than 4.0 points, and in the etalon it was 3.7 points. When the temperature dropped to minus 13-16 °C, the damage to the stool and overgrowing roots up to 2.0-2.5 points was noted. In this regard, the yield of the stocks was reduced by more than 2 times even for the most frost-resistant stocks (64-143, E-56).