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High demand for early-ripening sweet cherries and cherries necessitates enhanced cultivation methods, including adaptive rootstocks, to ensure productivity and quality amidst climate variability. Therefore, us study was conducted during 2018-2022 influence of clonal rootstocks on cherry and sweet cherry varieties in arid conditions. The research was carried out with the participation of cherry varieties Toy, Loznovskaya, Memory of Zhukova and sweet cherries Alexandria, Iput, Epos, Yaroslavna, adapted to the conditions of the Volgograd region, as well as clone rootstocks of the Crimean OSS RVL-2, RVL-9, LC-52, VSL-1, VSL-2. The survival rate of occultations on rootstocks in the nursery was studied, as well as the effect of clonal root-stocks on the growth and development of selected varieties in a garden. The productivity was calculated relative to biometric parameters: crown projection area (S), crown volume (V), stem cross-sectional area (S). The survival rate of varieties ranged depending on the rootstock from 55.9 to 49.1% and on the variety from 75 to 35.7%. The best indicators for the survival rate of vaccinations, more than 70%, were noted on variety--rootstock combinations: Epos/ RVL-1 -- 100%, Memory of Zhukova/RVL-2 - 71.4%, Iput/RVL-2 - 71.4%, Alexandria/ RVL-9 -- 71.4, Epos/RVL-9 -- 75%, Alexan-dria/VSL-1 -- 74% and Yaroslavna/VSL-2 -- 75%. The greatest growth of grafted plants was provided by the LC-52 rootstock, which is medium-sized. The weakest growth was observed on the rootstocks RVL-9 and VSL-1, which characterizes these rootstocks as dwarf. The highest productivity was noted for all varieties on the rootstocks RVL-2 and RVL-9, on average 5.8 and 4.9 kg/tree. [ABSTRACT FROM AUTHOR]

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Apple clonal rootstocks are the basis of modern intensive horticulture, providing a rapid increase in yield and convenience of fruit trees cultivation. Production of clonal rootstocks under high humidity often causes powdery mildew infection caused by the pathogenic fungus Podosphaera leucotricha Salm., which significantly reduces the productivity of stoolbed. Growing powdery mildew resistant genotypes is the most appropriate way to combat this disease and allows reducing the use of fungicides. To accelerate the search for resistant forms, molecular markers associated with resistance genes have been developed. However, these markers have not been used to study clonal rootstocks. The aims of the work were the field assessment of powdery mildew resistance of apple clonal rootstocks from the collection of the Michurinsk State Agrarian University and the screening of the collection for Pl-1, Pl-2, Pl-w and Pl-d resistance genes. The results of a three-year field evaluation of powdery mildew resistance of 80 rootstocks allowed us to distinguish five main groups ranging from very low to highly resistant. A group of 57 accessions was classified as powdery mildew resistant. The search for resistance genes was performed using the AT20 SCAR (Pl-1 gene), OPU02 SCAR (Pl- 2 gene), EM DM01 (Pl-d gene), and EM M02 (Pl-w gene) markers. The Pl-d and Pl-1 genes identified in 33 (41.25 %) and 31 (38.75 %) accessions, respectively, were the most common in the collection. The Pl-w gene was detected only in two accessions. Identification of the Pl-2 gene with the OPU02 SCAR marker did not reveal a fragment of the expected size. Thirty accessions with different powdery mildew resistance scores had two genes, Pl-1 and Pl-d, and highly resistant forms G16 and 14-1 had a combination of the Pl-d and Pl-w genes. These accessions can be used as donors of powdery mildew resistance for breeding new apple clonal rootstocks.

Aim of study: This study was conducted to determine the suitability of seven clonal and one seedling rootstocks for grafting of sour cherry cv. ‘Šumadinka’ trough early tree growth, precocity, productivity and fruit quality. Aim of study: To evaluate the suitability of seven clonal rootstocks and one seedling rootstocks for grafting the sour cherry cv. ‘Šumadinka’ based on early tree development, precocity, productivity and fruit quality. Area of study: A sour cherry orchard in village Prislonica, Serbia, near Čačak city. Material and methods: The sour cherry cultivar ‘Šumadinka’ was grafted onto Colt, MaxMa 14, Krymsk 6, Adara, Cigančica, Gisela 5, Gisela 6 and Myrobalan rootstocks. Standard and validated procedures were used to measure tree growth, productivity (from 2017 to 2020), leaf area, fruit physical properties and fruit chemical composition (from 2019 to 2020). Main results: Significant differences were observed among rootstocks in leaf and petiole dimensions, leaf area, tree vigour, yield, fruit size, soluble solids content, titratable acidity, sugars and vitamin C contents, ripening and sweetness indexes. Trees grafted on Adara exhibited the highest tree vigour, while those on Gisela 6 produced the largest fruit size. On the other hand, Colt trees generally displayed the highest sugar content and sweetness index. Adara also showed improvements in fruit quality characteristics, whereas the properties associated with Myrobalan received the lowest evaluation scores. Research highlights: Adara rootstock demonstrated good adaptability to heavy and acidic soil conditions in Serbia, even though it was originally selected for cherry cultivation in heavy, waterlogged, and calcareous soils in Spain. This adaptability likely contributed to its higher vigour, yield, yield efficiency and good fruit quality.

The period of operation of intensive orchards is 15 years. At the age of 6-7 years, the quality of fruits decreases sharply and the frequency of fruiting increases. In order to extend the productive period of the orchard, an experiment was laid on the effect of rejuvenating pruning on the productivity of an apple tree, depending on the variety-rootstock combination. In the course of this scientific study, in the period from 2020 to 2022, results were obtained indicating the presence of the potential for productivity of apple varieties of the Kazakhstani selection Voskhod and Talgarskoe on the introduced forms B 7-35, Arm 18 and the rootstock of the Kazakhstani selection Zhetysu 5 in which the solar radiation transmittance was from 0.45% to 0.77%. On this basis, all the studied varieties are superior to the control variant. It also improved the light space inside the tree crown, which increased the number of young growth points and contributed to the awakening of reserve buds. Young growing fruits, located in the middle and central parts of the crown, are better supplied with nutrients after pruning than before pruning. [ABSTRACT FROM AUTHOR]

Aim of study: To investigate the effect of different combinations of pear rootstocks and cultivars on the contents of leaf photosynthetic pigments and their relation with some growth and yield characteristics. Area of study: Ondokuz Mayis University, Samsun, Türkiye, in two years, 2021 and 2022. Material and methods: The pear cultivars ‘Santa Maria’, ‘Williams’, and ‘Deveci’ were grafted on eight rootstocks: two quince clonal rootstocks (BA29 and QA), five pear clonal rootstocks (FOX9, FOX11, OH×F333, OH×F87, FAROLD40) and Pyrus communis L. seedlings. Growth and yield attributes were calculated and chlorophyll and carotenoid contents were determined by the spectrophotometric method, using 99.8% methanol solvent for chlorophyll (chl) extraction. Main results: Chl a/b in the case of rootstocks, chl a and total carotenoids in the cultivars were found statistically significant; the ratio chl a/b ranged 1.71-2.30 in the case of rootstocks; in the case of cultivars chl a ranged from 17.77 (cv. ‘Santa Maria’) to 19.88 (cv. ‘Deveci’) μg mL-1, and carotenoids ranged 0.21-0.95 μg mL-1. Under the main impact of cultivars, rootstocks and their combinations, a significant difference was seen in the growth and yield attributes. Research highlights: A negative correlation coefficient was observed between photosynthetic pigments and morphological characteristics; however, the correlation coefficient was positive for canopy volume and annual shoot growth. Canopy management, especially with the use of rootstocks and cultivars that result in weaker growth, is helpful for improving chlorophyll content and yield performances.

The influence of three clonal rootstocks (‘Pixyʼ, ‘Fereleyʼ and ‘St. Julien Aʼ) along with seedlings of Myrobalan (control) on growth, yield and fruit quality of plum cultivars ‘Čačanska Najboljaʼ and ‘Čačanska Lepoticaʼ was studied in the Belgrade region (Serbia) for the six year-period (2013–2018). In comparison to control, clonal rootstocks have shown a significant effect on the decrease of trunk cross-sectional area. The lowest vigor was found in trees on the ‘Pixyʼ rootstock, then on ‘Fereleyʼ and ‘St. Julien Aʼ. Yield per hectare on trees grafted on clonal rootstocks was higher for 62–82% in ‘Čačanska Najboljaʼ, and for 26–27% in ‘Čačanska Lepoticaʼ compared to Myrobalan. In cultivar ‘Čačanska Najboljaʼ significantly higher fruit weight compared to control was obtained in the trees on the ‘Fereleyʼ and ‘St. Julien Aʼ rootstocks. The effects of rootstocks on the contents of soluble solids and total acids in the fruit were not significant. All three studied clonal rootstocks showed better results than standard Myrobalan, and can be recommended for establishing intensive plum plantations with higher planting density.

The influence of three clonal rootstocks ('Pixy', 'Fereley' and 'St. Julien A') along with seedlings of Myrobalan (control) on growth, yield and fruit quality of plum cultivars 'Čačanska Najbolja' and 'Čačanska Lepotica' was studied in the Belgrade region (Serbia) for the six year-period (2013-2018). In comparison to control, clonal rootstocks have shown a significant effect on the decrease of trunk cross-sectional area. The lowest vigor was found in trees on the 'Pixy' rootstock, then on 'Fereley' and 'St. Julien A'. Yield per hectare on trees grafted on clonal rootstocks was higher for 62-82% in 'Čačanska Najbolja', and for 26-27% in 'Čačanska Lepotica' compared to Myrobalan. In cultivar 'Čačanska Najbolja' significantly higher fruit weight compared to control was obtained in the trees on the 'Fereley' and 'St. Julien A' rootstocks. The effects of rootstocks on the contents of soluble solids and total acids in the fruit were not significant. All three studied clonal rootstocks showed better results than standard Myrobalan, and can be recommended for establishing intensive plum plantations with higher planting density. [ABSTRACT FROM AUTHOR]

Sour cherry (Prunus cerasus L.), having a rich composition of biologically active connections and antioxidants, is gaining increasing popularity among agricultural producers. Increasing the production of sour cherry fruits requires the introduction of modern technology, one of the elements of which is low-growing rootstocks. For many cultures, the use of low-growing rootstocks has been widely studied, but there is very little information on their use in cherry plantations. We studied new varieties and rootstocks of cherries in the conditions of the dry steppe zone, where this issue had not been studied before. Sour cherry (Prunus cerasus L.) varieties—Toy, Memory of Zhukova, and Loznovskaya—are the most adapted to the conditions in which the experiments were conducted. Russian breeding forms (Krymsk, Krasnodar region), which were taken as rootstocks, are widely used for sweet cherries (Prunus avium L.), but are practically never used for sour cherries (Prunus cerasus L.). The influence of rootstocks on such parameters as drought resistance, heat resistance, winter hardiness, and productivity was studied in variety–rootstock combinations. The study showed that they had the greatest drought resistance, and accordingly affected the grafted variety with rootstock, in the pedigree of which there are wild species. These rootstocks were of the VSL and RVL series. The study of the productivity of variety–rootstock combinations showed that in the grafted varieties the most rapid entry into the fruiting season and the greatest increase in the yield was facilitated by the rootstock forms of VSL-1 and VSL-2 (K5) which made it possible to obtain a yield of 5.8–8.1 kg/tree, depending on the variety grafted onto them. However, it is necessary to continue the research that has been started in order to fully determine the possible qualitative and quantitative parameters of the studied variety–rootstock combinations and to identify the most promising ones for further introduction into industrial production. This work was carried out within the framework of the topic of the state task of the Scientific Research Center of Agroecology of the Russian Academy of Sciences No. 0713-2019-0009: "Theoretical foundations, creation of new competitive biotypes of agricultural crops with high productivity, quality, sustainability and varietal technologies based on the latest methods and technological solutions in a changing climate, including seed breeding and nursery breeding". [ABSTRACT FROM AUTHOR]

"Negret" is the most widely planted hazelnut cultivar in Northeastern Spain, where it is highly appreciated by the local kernel marked for its favorable nut traits. Its main disadvantages are the high suckers emission, causing large maintenance costs every year, and its medium-to-low vigor and susceptibility to iron chlorosis. In 2000, a trial to select new vigorous and non-suckering rootstocks for hazelnut was established at IRTA Mas Bové (Spain). The "Negret N-9" selection was grafted onto four clonal rootstocks ("Dundee" and "Newberg" two selections of open-pollinated Corylus colurna seedlings, the low suckering cultivar "Tonda Bianca" and the local selection "IRTA MB-69") and compared to the self-rooted "Negret N-9" as a control. The trial was designed as a randomized complete block with 10 replications and one tree per plot (10 trees per treatment). Plant vigor, suckers emission, yield, and nut and kernel traits have been evaluated over 10 years (2003–2012). During the 2006 to 2010 growing seasons, the qualitative traits of kernels, such as kernel skin color, oil content, and fatty acid profiles, were added to the characterization. Physiological data, such as steam water potential, stomatal conductance, and leaf chlorophyll content, were also evaluated during the 2015 growing season. The results showed that clonal rootstocks had a strong influence on vigor and yield of "Negret N-9." The "Dundee," "Newberg," and "IRTA MB-69" rootstocks showed the highest vegetative growth and the lower suckers emission. The yield was highest in trees grafted on "Dundee" rootstock. In terms of the qualitative traits of kernel which are important to the hazelnut industry, rootstocks increased the oil stability and induced a brown light color in the kernel pellicle versus the brown dark color observed in nuts collected from self-rooted "Negret N-9." The fatty acids profile was also influenced by the grafting combination. Finally, physiological traits indicated a higher overall performances for "Dundee" rootstock, which was generally found to be the best rootstock for "Negret N-9" in the experimental environment. [ABSTRACT FROM AUTHOR]

“Negret” is the most widely planted hazelnut cultivar in Northeastern Spain, where it is highly appreciated by the local kernel marked for its favorable nut traits. Its main disadvantages are the high suckers emission, causing large maintenance costs every year, and its medium-to-low vigor and susceptibility to iron chlorosis. In 2000, a trial to select new vigorous and non-suckering rootstocks for hazelnut was established at IRTA Mas Bové (Spain). The “Negret N-9” selection was grafted onto four clonal rootstocks (“Dundee” and “Newberg” two selections of open-pollinated Corylus colurna seedlings, the low suckering cultivar “Tonda Bianca” and the local selection “IRTA MB-69”) and compared to the self-rooted “Negret N-9” as a control. The trial was designed as a randomized complete block with 10 replications and one tree per plot (10 trees per treatment). Plant vigor, suckers emission, yield, and nut and kernel traits have been evaluated over 10 years (2003–2012). During the 2006 to 2010 growing seasons, the qualitative traits of kernels, such as kernel skin color, oil content, and fatty acid profiles, were added to the characterization. Physiological data, such as steam water potential, stomatal conductance, and leaf chlorophyll content, were also evaluated during the 2015 growing season. The results showed that clonal rootstocks had a strong influence on vigor and yield of “Negret N-9.” The “Dundee,” “Newberg,” and “IRTA MB-69” rootstocks showed the highest vegetative growth and the lower suckers emission. The yield was highest in trees grafted on “Dundee” rootstock. In terms of the qualitative traits of kernel which are important to the hazelnut industry, rootstocks increased the oil stability and induced a brown light color in the kernel pellicle versus the brown dark color observed in nuts collected from self-rooted “Negret N-9.” The fatty acids profile was also influenced by the grafting combination. Finally, physiological traits indicated a higher overall performances for “Dundee” rootstock, which was generally found to be the best rootstock for “Negret N-9” in the experimental environment.

Sour cherry (Prunus cerasus L.), having a rich composition of biologically active connections and antioxidants, is gaining increasing popularity among agricultural producers. Increasing the production of sour cherry fruits requires the introduction of modern technology, one of the elements of which is low-growing rootstocks. For many cultures, the use of low-growing rootstocks has been widely studied, but there is very little information on their use in cherry plantations. We studied new varieties and rootstocks of cherries in the conditions of the dry steppe zone, where this issue had not been studied before. Sour cherry (Prunus cerasus L.) varieties—Toy, Memory of Zhukova, and Loznovskaya—are the most adapted to the conditions in which the experiments were conducted. Russian breeding forms (Krymsk, Krasnodar region), which were taken as rootstocks, are widely used for sweet cherries (Prunus avium L.), but are practically never used for sour cherries (Prunus cerasus L.). The influence of rootstocks on such parameters as drought resistance, heat resistance, winter hardiness, and productivity was studied in variety–rootstock combinations. The study showed that they had the greatest drought resistance, and accordingly affected the grafted variety with rootstock, in the pedigree of which there are wild species. These rootstocks were of the VSL and RVL series. The study of the productivity of variety–rootstock combinations showed that in the grafted varieties the most rapid entry into the fruiting season and the greatest increase in the yield was facilitated by the rootstock forms of VSL-1 and VSL-2 (K5) which made it possible to obtain a yield of 5.8–8.1 kg/tree, depending on the variety grafted onto them. However, it is necessary to continue the research that has been started in order to fully determine the possible qualitative and quantitative parameters of the studied variety–rootstock combinations and to identify the most promising ones for further introduction into industrial production. This work was carried out within the framework of the topic of the state task of the Scientific Research Center of Agroecology of the Russian Academy of Sciences No. 0713-2019-0009: “Theoretical foundations, creation of new competitive biotypes of agricultural crops with high productivity, quality, sustainability and varietal technologies based on the latest methods and technological solutions in a changing climate, including seed breeding and nursery breeding”.

The basic shoot characteristics of 'Karina' and 'Sylvia' sweet cherry (Prunus avium L.) trees grafted on Gisela 3, Gisela 5, Piku 4, Weiroot 72 and F12/1 rootstocks were examined 3 years after planting. In both cultivars, F12/1 achieved a greater shoot length (SL) and diameter (SD) and a lower number of flower clusters per cm SL (NFC·cm−1 SL) than the other rootstocks. Furthermore, although the two cultivars had different growth vigour, they exhibited similar differences in SL, SD and NFC·cm−1 SL among the rootstocks. The correlation between SL and NFC·cm−1 SL was 34.4% and 39.9% greater than the correlation between SD and NFC·cm−1 SL in 'Karina' and 'Sylvia', respectively. Regression analysis for both cultivars on particular rootstocks and for the mean values across the rootstocks showed that there was a logarithmic relationship between SL and NFC·cm−1 SL, with r2 values of 0.703 and 0.694 for 'Karina' and 'Sylvia', respectively, when the responses were fitted by logarithmic function models. The minimum and maximum NFC·cm−1 SL predicted by these models were approximately 0.01 and 0.9 (for SL = 145 and 7 cm, respectively) for 'Karina' and 0.0 and 0.9 (for SL = 150 and 5 cm, respectively) for 'Sylvia'. These findings combined with data obtained in previous studies suggest that NFC·cm−1 SL can be used as an index for predicting the fruiting potential of young sweet cherry trees. [ABSTRACT FROM AUTHOR]

The paper examines the influence of three clonal rootstocks ('Pixy', 'Fereley' and 'St. Julien A') along with seedlings of Myrobalan (control) on the growth, yield and fruit quality of the plum cultivar 'Čačanska Rana'. Research was conducted in the area of the Belgrade Danube basin for the six-year period (2013-2018). In comparison to control, all three clonal rootstocks have shown a significant effect on the decrease of vigor expressed as a trunk cross-sectional area. The lowest vigor was found in trees on the 'Pixy' rootstock, then on 'Fereley' and 'St. Julien A' rootstocks. Regarding the rootstocks 'Fereley' and 'St. Julien A', significantly higher fruit set and yields were achieved in comparison to control. Clonal rootstocks induced an increase in the yield per hectare ranging from 72% to 93% compared to Myrobalan. The highest yield efficiency was found in the trees on the 'Fereley' rootstock, followed by the yields observed in the trees on the 'Pixy' and 'St. Julien A' rootstocks. Significantly higher fruit weight compared to control was obtained in the trees on the 'Fereley' rootstock. Rootstocks did not show any significant effect on the soluble solids and total acid contents of the fruit. Based on the results obtained, it can be concluded that all three clonal rootstocks showed better results than Myrobalan, and can be recommended for establishing intensive plum plantations with higher planting density. The best results in terms of yield and fruit quality were obtained with the 'Fereley' rootstock.

Sources and donors of traits important for clonal rootstock breeding have been selected from the genetic diversity of Prunus L. numbering over 5000 genotypes maintained at Krymsk Experimental Breeding Station: adaptability to biotic and abiotic stresses, easy vegetative reproduction ability, dwarfness, etc. As a result of prebreeding, donors combining several breeding traits have been developed.

In the new introducing almond areas, it is necessary to test the more promising almond cultivar and rootstock combinations able to guarantee the best agronomic performances according to the specific pedoclimatic conditions. With this aim, two almond trials have been established in an experimental farm located in the Latium region (Italy). The first trial (A) focused on the phenological, and agronomical influences induced by the clonal rootstock ‘GF677’ on the grafted cultivars ‘Tuono’, ‘Supernova’ and ‘Genco’, in comparison to those induced by peach seedling rootstocks, in order to identify the best grafting combination for developing “high density” plantings in this new growing area. The second trial (B) tested the phenological and agronomical influences induced by three different clonal rootstocks (‘GF677’, ‘Rootpac® 20’ and ‘Rootpac® R’), on the Spanish cultivar ‘Guara’ to identify suitable dwarfing rootstocks for “super high density” plantings in the same environment. Flowering and ripening calendars of the trial A highlighted as the medium-late flowering cultivars ‘Genco’, ‘Supernova’ and ‘Tuono’ could be subject to moderate risk of cold damages. The clonal rootstock ‘GF677’ seems to anticipate flowering and vegetative bud break by a few days in ‘Tuono’ when compared to the same cultivar grafted on peach seedling rootstocks. Furthermore, the yield per plant was always higher in plants grafted on ‘GF677’. The observations carried out in trial B highlighted as the flowering of cultivar ‘Guara’ were affected by the rootstock, with ‘Rootpac® 20’, which postponed its full bloom of about one week when compared to other rootstocks, whereas ‘GF677’ imposed more vigor to the cultivar than ‘Rootpac® 20’ and ‘Rootpac® R’.

In recent years, research has focused on phenolic compounds and their putative role as markers of graft incompatibility. Thus far, no studies have been conducted on the role of phenolic compounds in chestnut (Castanea spp.). The present study investigated the content of phenolic compounds in different combinations of Castanea spp. cultivars and rootstocks. Analyses were performed on the inner and outer tissues of chestnut grafts at two phenological sampling stages. The separation, identification and quantification of the phenolic markers via HPLC were preceded by an ultrasonic green extraction. Two chromatographic methods were tested for a total of 15 phenol compounds. Flavonol compounds were not detected, while cinnamic acids were found in low concentrations. The amount of gallic acid turned out to be higher at the graft union of the incompatible combination (20.11 ± 1.47 mg/100 gFW vs. 8.94 ± 1.08 mg/100 gFW). The same pattern was observed for catechin (15.79 ± 1.83 mg/100 gFW vs. 9.63 ± 1.98 mg/100 gFW). Differences in tannin concentrations seemed to be species-specific, and were apparently not related to graft incompatibility. The present work underlines the potential application of certain phenol compounds for the early prediction of graft incompatibility in Castanea spp.

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The basic physiological and biometric parameters of zoned (62-396, 54-118, 57-545) and introduced (P60, P59, P22) apple clonal rootstock with various growth vigor in the intensive cuttings' nursery with the use of organic substrate were comparatively assessed. It has been found that over 8 years of study in the conditions of the Central Black Soil belt of the Russian Federation, the introduced rootstocks in terms of environmental sustainability were virtually at the level of zoned apple rootstocks. The results of many years' research about the characteristics of apple clonal rootstock root system formation, leaf area, the productivity of leaves' photosynthesis and accumulation of the vegetative mass in various plant organs within the vegetation period have been presented. It has been found that in the nursery, accumulation of the biomass in cuttings of various rootstocks largely depends on their leaf area (r = 0.93). The high correlation between rootstocks' growth vigor and the leaf area per 1 meter of the nursery (r=0.91) has been found. On the eighth productive year, the total leaf area per 1 ha of the nursery for rootstocks 62-396 was 18.1 thousand m2, for P60 - 23.1 thousand m2, and for rootstocks 54-118 and 57-545 - 24.4 thousand m², which shows the intensive use of the land area and solar energy. The leaf area index in mother plant rows reached 7.3-9.8 m²/m².It has been found that the introduced rootstocks had a very low coefficient of roots' branching, their number of root endings was 2.2-2.9 times smaller than in zoned rootstocks. In zoned rootstocks, higher photosynthetic activity of leaves was revealed, compared to the introduced rootstocks. Thus, the difference in the productivity of leaves' photosynthesis was 12-18%. During the vegetation season, 1m² of leaves of the cuttings of rootstock 62-396 synthesized the largest amount of assimilates in terms of final biomass - 566 g of dry matter. Over the years of research, the best indicators of cuttings' quality in the intensive nursery were on the average observed in forms 62-396, P60 and 54-118, the yields of the first and second grade for them were 55-58%. [ABSTRACT FROM AUTHOR]

In the study, the effects of some plant growth hormones and plant activators on the rooting of Rootpac-40 and GF 677 almond clonal rootstock cuttings were defined. The annual Rootpac-40 and GF677 clonal almond (P. dulcis L.) rootstocks were studied in a growth room (220C±1) in randomized blocks design with 4 replicates, and the plant growth regulators used were IBA (Indole-3-butyric acid), IAA (Indole-3-acetic acid), SA (Salicylic acid) and Messenger Gold (MG). In Rootpac-40, the highest live cutting quantity was observed in control (95.00%), and MG (85.50%) was placed statistically in the same group with control. The lowest amount of live cutting was observed in IAA (57.50%). In GF 677, the highest number of live cutting was observed in IBA (85.00%), which was followed by IAA (75.00%). The lowest number of live cutting was observed in control (50.00%) and MG (57.00%) practises. While the cutting diameter values ranged between 4.04 mm - 6.29 mm in both rootstocks, the highest cutting diameter was observed in MG (6.29 mm), IAA (6.25 mm) and IBA (5.71 mm). The lowest cutting diameter on the other hand, was observed in the SA (4.04 mm). In conclusion, the number of live cuttings in Rootpac-40 was increased by MG, while in GF 677, IBA was the factor that increased the number. MG, IAA and IBA were created positive effects on the cutting diameter of both rootstocks. [ABSTRACT FROM AUTHOR]

Overview on Prunus mahaleb L. rootstock breeding and evaluation compile the knowledge on variability, rootstock traits based on systematic evaluation and results achieved in previous breeding projects. Conclusion is that adaptability of mahaleb cherry to continental climate, tolerance to drought, hot summer, poor soils, high pH and lime tolerance are valuable rootstock traits considering the forecasted environmental conditions due to the climate changes. The diverse rootstock usage in vigor control is the present situation in the sweet and sour cherry growing. This diverse rootstock usage might be continued for the future too, when training system and rootstock are considered together, matched properly with the vigor of orchard site. There are few clonal rootstocks showing vigor 65–70% compared to seedlings with medium precocity. Further on the potential in compact or spur type mahalebs, genetic dwarf genotypes or inbred lines are still not fully utilized in mahaleb cherry breeding. Possible interspecific crosses between P. mahaleb and other cherry species ( Prunus avium and Prunus fruticosa crosses are known yet) also could extend the range of desired growth control and precocity. Traditional seed tree selection resulted in seed tree clone, producing high quality seedlings for sweet- and sour cherry growing but their vigor control and precocity does not meet all the requirements of modern pedestrian orchards. Variability of mahaleb cherry manifested in selected genotypes, inbred lines and potential of interspecific crosses promise progress in those directions that are desired rootstock traits in vigor control, precocity and environmental adaptability. [ABSTRACT FROM AUTHOR]

The infl uence of the rootstocks МАС 9, М 9, М 26 and ММ 106 upon the temperate growing cultivar Golden Resistant was studied over three years. The rootstock МАС 9 induced the lowest tree sizes, while ММ 106 induced the largest sizes. The decreasing effect of МАС 9 is expressed also in the lowest total growth during the studied period. Regarding the reproductive behaviour totally for this period МАС 9 has formed the signifi cantly highest number of fruit-buds compared to all the rest of the rootstocks.

The current global agricultural challenges imply the need to generate new technologies and farming systems. In this context, rootstocks are an essential component in modern agriculture. Most currently used are those clonally propagated and there are several ongoing efforts to develop this type of plant material. Despite this tendency, lesser number of rootstock breeding programs exists in comparison to the large number of breeding programs for scion cultivars. In the case of rootstocks, traits evaluated in new selection lines are quite different: From the agronomic standpoint vigor is a key issue in order to establish high-density orchards. Other important agronomic traits include compatibility with a wide spectrum of cultivars from different species, good tolerance to root hypoxia, water use efficiency, aptitude to extract or exclude certain soil nutrients, and tolerance to soil or water salinity. Biotic stresses are also important: Resistance/tolerance to pests and diseases, such as nematodes, soil-borne fungi, crown gall, bacterial canker, and several virus, viroids, and phytoplasms. In this sense, the creation of new rootstocks at Centro de Estudios Avanzados en Fruticultura (CEAF) offers an alternative to stone fruit crop, particularly in Chile, where just a few alternatives are commercially available, and there are site-specific problems. The implementation of molecular markers in order to give support to the phenotypic evaluation of plant breeding has great potential assisting the selection of new genotypes of rootstocks. Marker-Assisted Selection (MAS) can shorten the time required to obtain new cultivars and can make the process more cost-effective than selection based exclusively on phenotype, but more basic research is needed to well understood the molecular and physiological mechanisms behind the studied trait. [ABSTRACT FROM AUTHOR]

The most common rootstock for Juglans regia (Persian or "English" walnut) in California is Paradox, typically a hybrid of J. hindsii (Northern California black walnut) x J. regia. Unfortunately, Paradox is very susceptible to Armillaria root disease. The relative resistance to Armillaria mellea of six clonally propagated Paradox rootstocks (AX1, Pxl, RR4 11A, RX1, Vlach, VX211) was evaluated and compared with that of clonally propagated J. hindsii rootstock selection W17, J. regia scion cultivar Chandler, and Pterocarya stenoptera (Chinese wingnut). In a growth-chamber assay, plants were micropropagated and rooted in vitro before inoculating the culture medium with A. mellea. At two months post-inoculation, the most resistant and susceptible Paradox rootstocks were AX1 and VX211, respectively, with 9% vs. 70% mortality, and this finding was consistent across three isolates of A. mellea and three replicate experiments. This broad range of resistance within Paradox is consistent with past field trials that tested other genotypes. Our finding of similarly high susceptibility of 'Chandler' and W17 (61% vs. 69% mortality) is in contrast to two field trials, in which other /. regia genotypes were more susceptible than those of J. hindsii. A third trial, however, identified some J. regia genotypes as more resistant than those of J. hindsii. Therefore, it is possible that W17, which was not previously tested, is an Armillaria-susceptible genotype of J. hindsii. Based on our findings of repeatable mortality levels across three isolates of A. mellea and three replicate experiments, the growth-chamber assay has promise, albeit with confirmed resistant and susceptible controls, for identifying putative resistant rootstocks (e.g., AX1) in preparation for a field trial with controlled inoculations. [ABSTRACT FROM AUTHOR]

pple replant disease (ARD) is a soil-borne disease complex that affects young apple trees in replanted orchards, resulting in stunted growth and reduced yields. Newly developed rootstock genotypes with tolerance to ARD may help to control this disease. We determined the effects of rootstock genotype rotations during orchard renovation, by investigating root-zone soil microbial consortia and the relative severity of ARD on seven rootstock genotypes (M.9, M.26, G.30, G.41, G.65, G.935, and CG.6210) planted in soil where trees on four of those same rootstocks (M.9, M.26, G.30 and CG.6210) had grown for the previous 15 years. Rootstock genotyping indicated that genetic distances among rootstocks were loosely correlated with their differential responses to ARD. Root-zone fungal and bacterial community composition, assessed by DNA fingerprinting (T-RFLP), differed between M.26 and CG.6210. Soil bacterial communities were influenced most by which rootstock had grown in the soil previously, while fungal communities were influenced more by the current replanted rootstock. In a clone library of bacteria from M.26 and CG.6210 root-zone soil, β-Proteobacteria was the most abundant phylum (25% of sequences). Sequences representing the Burkholderia cepacia complex were obtained only from CG.6210 soil. Rootstock genotypes that were grown in the orchard soil previously affected subsequent ARD severity, but replanting with the same or closely related rootstocks did not necessarily exacerbate this disease problem. Our results suggest that genotype-specific interactions with soil microbial consortia are linked with apple rootstock tolerance or susceptibility to ARD. [ABSTRACT FROM AUTHOR]

In recent years, research has focused on phenolic compounds and their putative role as markers of graft incompatibility. Thus far, no studies have been conducted on the role of phenolic compounds in chestnut (Castanea spp.). The present study investigated the content of phenolic compounds in different combinations of Castanea spp. cultivars and rootstocks. Analyses were performed on the inner and outer tissues of chestnut grafts at two phenological sampling stages. The separation, identification and quantification of the phenolic markers via HPLC were preceded by an ultrasonic green extraction. Two chromatographic methods were tested for a total of 15 phenol compounds. Flavonol compounds were not detected, while cinnamic acids were found in low concentrations. The amount of gallic acid turned out to be higher at the graft union of the incompatible combination (20.11 ± 1.47 mg/100 gFW vs. 8.94 ± 1.08 mg/100 gFW). The same pattern was observed for catechin (15.79 ± 1.83 mg/100 gFW vs. 9.63 ± 1.98 mg/100 gFW). Differences in tannin concentrations seemed to be species-specific, and were apparently not related to graft incompatibility. The present work underlines the potential application of certain phenol compounds for the early prediction of graft incompatibility in Castanea spp. [ABSTRACT FROM AUTHOR]

In the new introducing almond areas, it is necessary to test the more promising almond cultivar and rootstock combinations able to guarantee the best agronomic performances according to the specific pedoclimatic conditions. With this aim, two almond trials have been established in an experimental farm located in the Latium region (Italy). The first trial (A) focused on the phenological, and agronomical influences induced by the clonal rootstock 'GF677' on the grafted cultivars 'Tuono', 'Supernova' and 'Genco', in comparison to those induced by peach seedling rootstocks, in order to identify the best grafting combination for developing "high density" plantings in this new growing area. The second trial (B) tested the phenological and agronomical influences induced by three different clonal rootstocks ('GF677', 'Rootpac® 20' and 'Rootpac® R'), on the Spanish cultivar 'Guara' to identify suitable dwarfing rootstocks for "super high density" plantings in the same environment. Flowering and ripening calendars of the trial A highlighted as the medium-late flowering cultivars 'Genco', 'Supernova' and 'Tuono' could be subject to moderate risk of cold damages. The clonal rootstock 'GF677' seems to anticipate flowering and vegetative bud break by a few days in 'Tuono' when compared to the same cultivar grafted on peach seedling rootstocks. Furthermore, the yield per plant was always higher in plants grafted on 'GF677'. The observations carried out in trial B highlighted as the flowering of cultivar 'Guara' were affected by the rootstock, with 'Rootpac® 20', which postponed its full bloom of about one week when compared to other rootstocks, whereas 'GF677' imposed more vigor to the cultivar than 'Rootpac® 20' and 'Rootpac® R'. [ABSTRACT FROM AUTHOR]