Potcelma Krymsk-1 ietekme uz plūmju jaunkoku ražu = The effect of rootstock Krymsk-1 on the yield of young plum tree

In Latvian gardens height-reducing rootstocks for growing plum trees have been introduced at a very small scale. It is possible to plant more trees per unit of an area when growing trees of smaller height and, in addition, less time is spent on their formation, because the volume of the crowns is smaller. Crop care and harvesting are easier because the trees are lower. The most widely used rootstock, not only in Latvia but also in other European countries, is the seedling rootstock P. cerasifera. In this trial, this rootstock was compared with the Krymsk-1 (VVA-1) rootstock, which reduces tree height the most significantly. The trial was established in the spring of 2015 without an irrigation system in the garden of the Institute of Horticulture in Dobele. The cultivars ‘Victoria’ and ‘Jubileum’ were included in the study. The measurements used in the study had the average yield per tree (kg) in the period from 2018 to 2022, and the calculated yield per trunk cross-sectional area in 2022. The average yield per tree on average for all years for the cultivar ‘Victoria’ on P. cerasifera was 14 kg, on Krymsk-1 4 kg; for the cultivar ‘Jubileum’ on P. cerasifera 5 kg, on Krymsk-1 2 kg. The average yield per trunk cross-sectional area for the cultivar ‘Victoria’ on P. cerasifera was 0.49 kg cmE−2, on Krymsk-1 0.40 kg cmE−2; for the cultivar ‘Jubileum’ on P. cerasifera 0.09 kg cmE−2, on Krymsk-1 0.14 kg cmE−2. The visual evaluation of the trees growing in the trial revealed that the growth of the cultivar ‘Victoria’ had been reduced very strongly, and the annual shoots were very short therefore strong spring pruning was necessary to obtain sufficient new growth. The height of the cultivar ‘Jubileum’ was moderately reduced, and the crown formation was easier.