Evaluation of apple-tree clonal rootstocks from the Michurinsk State Agricultural University in the nursery of the Leningrad Region

Abstract

The introduction of apple-tree clonal rootstocks into the Leningrad Region requires their evaluation under the specific soil and climatic conditions. The studies were conducted in the educational and experimental orchard of the Saint Petersburg State Agricultural University from 2020 through 2023. Layer vertical type parent stock of clonal rootstocks of apple-tree developed in the Michurinsk State Agricultural University was set up in open ground. The following rootstocks were tested: 54-118, 57-490, 62-396, 62-223, 71-3-150, and Malysh Budagovskogo. The last three forms of rootstocks were tested for the first time in the region. It was determined that the full seasonal development cycle of the apple-tree rootstock forms with the formation of layers in the Leningrad Region showed that the biological rhythms of these genotypes were well-suited to the conditions of the introduction region. The graft survival rate was 82.9-90.0% when grafting the Mantet and Papirovka varieties onto the studied rootstocks. Additionally, the highest growth was observed in one-year-old seedlings of the Mantet / 57-490, Papirovka / 54-118, Papirovka / 57-490, and Papirovka / 62-223 combinations. The tallest two-year-old Mantet seedlings were recorded on rootstocks 57-490, 62-223, 71-3-150, and 54-118, ranging from 152.8 to 160.4 cm, while the shortest were in the Mantet / Malysh Budagovskogo combination (130.5 cm). The height of two-year-old Papirovka seedlings ranged from 142.6 cm (Papirovka / Malysh Budagovskogo) to 172.3 cm (Papirovka / 57-490). The stem diameter of two-year-old seedlings in the studied variety-rootstock combinations ranged from 12.5 to 15.6 mm. Papirovka seedlings formed fewer lateral branches on all studied rootstocks compared to Mantet variety. For Mantet seedlings, the root system length ranged from 34.4 cm (Mantet / Malysh Budagovskogo) to 45.5 cm (Mantet / 54-118), while for Papirovka seedlings, it ranged from 32.3 cm (Papirovka / Malysh Budagovskogo) to 40.2 cm (Papirovka / 57-490). The clonal rootstocks 62-223, 71-3-150, and Malysh Budagovskogo studied under the conditions of Northwestern Russia showed promising results for growing in the region’s fruit-farming industry.