Field performance of grafted fruit-tree rootstocks was not affected by micropropagation

Abstract

The use of micropropagated trees has been widely extended, since micropropagation is a convenient technique of vegetative propagation that shows a number of interesting advantages, mainly for woody fruit trees. However, only few studies can be found in the literature on the field performance of micropropagated trees. In this work, the performance of different micropropagated fruit-tree rootstocks, grafted with some peach and nectarine varieties, was compared with grafted rootstocks propagated by conventional methods. The Prunus rootstocks ‘Adafuel’, ‘Adarcias’ (both, almond x peach hybrids) and ‘Adesoto 101’ show different problems when propagated by conventional techniques that reduce the propagation rate, including: low percentage of rooting (‘Adesoto 101’, ‘Adarcias’), roots of bad quality (‘Adarcias’), excessive vigor in the nursery and uneven growth (‘Adafuel’). However, micropropagation solved these problems supplying uniform plants with good behavior and size in the nursery. Both plant types, micropropagated or cutting-derived plants, were grafted with different varieties: ‘Adafuel’ and ‘Adarcias’ were grafted with the varieties ‘Baby Gold 5’, and ‘Super Crimson Gold’, and ‘Adesoto 101’ with ‘Catherine’ and the selection NJC 97. After one year of growth in the nursery, suitable trees were planted in the field. Data obtained during the first years of field growth suggest that the rootstock propagation method did not seem to influence the field performance of fruit trees, since no remarkable differences were observed, for each combination rootstock/scion, between the different propagation methods for any of the observed characters: crop production, vigor, fruit weight, yield, and fruit quality (soluble solids concentration - SSC, pH, acidity, firmness) and color.