Influence of rootstock on plum trees performance during the early years after grafting

Plum cultivars (×13) were grafted on Prunus cerasifera and on ‘Wangenheim Prune’ (P. domestica) seedlings and compared for 4 successive years after planting in the orchard. Several vegetative and reproductive traits were monitored including trunk diameter, flowering intensity, yield, fruit weight, soluble solids content (SSC) and the yield efficiency index was determined, too. Cultivar ‘Kubanskaya Kometa’ was the most precocious. It started to yield in the first year after the planting. Cultivars ‘Kubanskaya Kometa’, ‘Violeta’, ‘Valor’, ‘Stanley’ and ‘Oda’ showed the highest yield in the young orchard. Cultivars ‘Jubileum’, ‘Kijevas vēlā’ and ‘Cacanska Rana’ produced attractive large tasty fruit: their weight reached 55-59 g and taste was estimated at 4.4-4.6 points in 1-5 score scale. The ‘Wangenheim Prune’ rootstock reduced tree trunk diameter by 29% in comparison with P. cerasifera seedlings. Average fruit yield per plot was 34% higher from trees grafted on P. cerasifera rootstock. Only yield efficiency of ‘Kubanskaya Kometa’ and ‘Valor’ were influenced by rootstock being higher when grafted on P. cerasifera. Rootstock had no effect on average fruit weight and SSC.