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The agronomic performance and leaf mineral nutrition of the non-melting clingstone peach cv. 'Catherina' was evaluated on seven hexaploid plum rootstocks, as well as one Prunus persica seedling. They were assessed over a period of 15 years in a field trial at the Experimental Station of Aula Dei-CSIC (Zaragoza, Spain), located in the Ebro Valley (NE Spain). Growing conditions generated varying levels of tree mortality, the highest with Constantí 1, Monpol and Montizo, whereas all Adesoto, GF 655/2 and PM 105 AD trees survived well. GF 655/2 and P. Soto 67 AD proved to be the most dwarfing rootstocks, while Constantí 1 and Monpol were the most invigorating and generated greater cumulative yields. However, the highest yield efficiency was recorded on GF 655/2 and Montizo, although they did not differ significantly from Adesoto and P. Soto 67 AD. The highest average values for fruit weight were observed on PM 105 AD and the lowest on GF 655/2, but they did not differ significantly from the rest of the rootstocks. The highest average values for the soluble solids content were observed on the Pollizo rootstocks Adesoto and PM 105 AD, followed by P. Soto 67 AD. All rootstocks induced nitrogen deficiency, with the exception of Constantí 1, GF 655/2 and Montizo, and iron deficiency, except PM 105 AD. The invigorating rootstock Constantí 1 seemed to induce higher SPAD values. According to the ΣDOP index, Montizo presented the most suitable balanced nutritional index, but it did not differ significantly from the rest of the rootstocks except GF 655/2 and P. Soto 67 AD.Additional key words: iron chlorosis; vigour; yield; SSC; SPAD.Correspondence should be addressed to María Angeles Moreno: mmoreno@eead.csic.es Authors' contributions: MAM has designed and conducted the study since 1997. LM collected samples and performed the leaf mineral, SPAD and fruit quality analysis. JAB supervised the leaf mineral analysis. MAM supervised the research and guided data interpretation. LM, GR and MAM carried out statistical analysis and wrote the manuscript. All authors read and approved the final manuscript. Competing interests:The authors have declared that no competing interests exist.

Agronomic and physicochemical fruit properties of 'Big Top' nectarine were evaluated in the Ebro Valley (Zaragoza, Spain), under replant and heavy-calcareous soil conditions typical of the Mediterranean area. Fruits were harvested at commercial maturity from trees budded on four peach-almond hybrids (Prunus amygdalus × Prunus persica): Adarcias, Felinem, GF 677 and Mayor; two P. persica × Prunus davidiana hybrids: Barrier and Cadaman; two hexaploid plums: Adesoto (Prunus insititia) and Tetra (Prunus domestica); and one almond-plum hybrid (Prunus cerasifera × P. amygdalus): Replantpac. Significant differences among the different rootstocks were found for most of the fruit quality traits analyzed at harvest maturity. The average of the four years of study showed that the brightest (high L* value) and most red colored skin fruits (high a* and b* values) were found on GF 677, while the lowest b* and h were recorded on Tetra and Felinem, respectively. Adesoto, GF 677 and Replantpac induced good fruit quality traits based on anthocyanins, Vitamin C, relative antioxidant capacity and/or total phenolic content (TPC). GF 677 also showed higher values on cumulative yield (CY) and yield efficiency (YE), with no significant differences with Replantpac for CY and Adesoto for YE. Barrier and Cadaman seem to delay maturity of 'Big Top' fruits based on flesh firmness (FF), titratable acidity (TA) and CIELAB parameters, and showed lower TPC and anthocyanins, which could be partly explained due to their worst adaptation to calcareous soil conditions. Results from this study underlined the important relationships between plant adaptability and fruit quality traits.

Since there are many different factors which affect peach orchard profitability, it is necessary to conduct long-term studies to find the best scion/rootstock combination within the constraints imposed by local climate and economic conditions. The influence of six peach-almond hybrids (“Adafuel”, “Adarcias”, Garnem”, “GF 677”, “PADAC 9902-01” and “Rootpac 70”); one P. persica × P. davidiana hybrid: “Cadaman”; five hexaploid plums (“Adesoto 101”, “PM 44 AD”, “PM 105 AD”, “PM 150 AD”, and “Penta”); three plum × peach-almond hybrids (“PADAC 04-01”, “PADAC 04-03” and “PADAC 99-05”), and one plum x almond hybrid (“Rootpac R”) on agronomic, basic fruit quality parameters, and flower and leaf mineral nutrients of the “Big Top” nectarine was tested. The highest vigor was induced by “Adafuel”, while the lowest vigor was exhibited by “PM 105 AD”, although the latter did not differ from the rest of the rootstocks. Yield efficiency was higher for “Adesoto 101” and lower for “Adafuel”. Regarding the soluble solids content (SSC), “PADAC 04-01” rootstock induced the highest average content, although it did not differ from “Adarcias”, “Adesoto 101”, “PADAC 99-05”, “PM 105 AD”, and “Rootpac R”. In addition, significant effect of rootstock was found on the flower and leaf mineral analysis traits evaluated. The medium (“Adarcias”, “Adesoto 101”, “PM 105 AD”) to high vigorous plum based hybrid rootstocks (“PADAC 04-01”, “PADAC 99-05” and “Rootpac R”) showed the tendency to induce a better fruit quality, based on higher concentration of SSC, and other yield attributes, demonstrating their commercial interest as new rootstocks for peaches. Considering its overall performance, “PADAC 04-01” appears as a new promising rootstock alternative to peach-almond hybrids on heavy and calcareous textured soils.

Field performance, leaf mineral content and fruit quality of two 'Greengage' plum cvs. 'R.C. Bavay' and 'R.C. GF 1119' budded on two plum based rootstocks (Ishtara and P.8-13) were studied in the network of an international European plum trial, promoted by the Fruit Research Station of the INRA of Bordeaux (France) and other European Research Centers. Trees were established in the winter of 1993-1994 in a heavy and calcareous soil with climate conditions typical of the Mediterranean area. Trees of 'R.C. GF 1119' were more vigorous than those from 'R.C. Bavay'. The highest yield was observed on the P.8-13 rootstock for both cultivars. In contrast, the highest cumulative yield and yield efficiency were induced by 'R.C. Bavay', independently of the rootstock. All trees budded on Ishtara survived well, whereas tree mortality was reported in trees budded on P.8-13 for each cultivar. Leaf chlorophyll content varied depending of the rootstock-scion combination. Most of the mineral nutrient concentrations were not affected by the rootstock-scion combination, with the exception of Mn, which was significantly lower on Ishtara for both cultivars. Overall, Ishtara resulted the best adapted rootstock to soil waterlogging and calcareous soil conditions showing a good tree survival and best leaf Fe mineral content. Further studies with plum varieties budded onto P.8-13 rootstock should be carried out to in order to recommend their use on soils with no waterlogging and/or associated diseases. Comparing the two cultivars, 'R.C. Bavay' showed better agronomic performance than 'R.C. GF 1119', in terms of cumulative yield and yield efficiency, and similar good fruit quality.

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INTRODUCTIONPeach (Prunus persica) is one of the most important fruit grown in the world. Spain is the first exporter of peaches in the world, and currently the largest producer in the EU (Reig et al., 2017). In Spain, peach production contributes to the large production of stone and pome fruits and its production represents 4.5% of total Spanish horticultural products. The main peach producing area is the Ebro Valley (regions of Aragon and Catalonia) accounting for more than 60% of total Spanish production (MAPAMA, 2017).'Big Top' is nowadays considered the reference nectarine cultivar in Europe for fresh consumption, known as a slow-softening rate cultivar and appreciated for its early coloration resulting in highly colored fruit, optimum fruit size, high sweetness, juiciness and flavor (Reig et al., 2016). Different studies with Prunus spp. revealed that rootstocks influence agronomic performance such as tree vigor, yield efficiency, and fruit quality (