Search Results (24)

Dormancy breakers are widely employed in regions with an insufficient chill accumulation to enhance floral bud break in sweet cherry production. Dormex (HC) has not been authorized in Europe and many other countries due to its detrimental effects on human health (carcinogenic) and the environment. This situation has increased the demand for alternative chemicals to HC. The current study was conducted in an orchard of 5-year-old ‘Royal Tioga^®’ sweet cherry trees (Prunus avium L.) grafted on MaxMa 14 rootstocks in the Karayusuflu Village (at an altitude of 50 m), Adana, a Mediterranean city in Türkiye. Levante (LV) and HC were applied approximately 30 days before the anticipated dormancy break of the buds. Chill accumulation was quantified monthly during the 2023–2024 winter season using the chilling hours below 7.2 °C (467 h) and chill units (280 CUs). This study evaluated the effects of dormancy breakers on hormonal changes in floral buds, focusing specifically on gibberellic acid (GA₃) and abscisic acid (ABA). Also, their impact on fruit set and quality parameters was assessed. The findings revealed that the LV and HC applications reduced the ABA content in flower buds during the dormancy period compared to the control. LV significantly improved bud break rates (56.8%) and fruit set (85.2%) while positively influencing the fruit quality parameters and yield. No significant differences between the LV and HC treatments were observed regarding average fruit weight (8.8–8.4 g) and yield values (3.7–3.5 kg tree⁻¹). These results suggest LV as an alternative to HC for early-season cherry production in warm climates. Full article

In the winter season, citrus nursery production faces challenges including shorter days, lower light levels, and lower temperatures that delay vegetative budbreak and scion shoot growth. With the goal of improving the production cycle in the citrus nursery, we investigated the effect of supplemental LED light on the production of bud-grafted citrus trees during short winter days. Three experiments were conducted under different temperature conditions. “Washington” Navel sweet orange (Citrus sinensis) was budded on Carrizo citrange (C. sinensis × Poncirus trifoliata) and Rubidoux trifoliate (P. trifoliata) rootstocks in early December. Light treatments included no supplemental light, day-length extension to 16 h with LED light, and night interruption (1 h of LED light at night). Day-length extension and night interruption were studied with and without preconditioning plants with the respective light treatments for 6 weeks before grafting. Day-length extension increased the scion growth, but only when supplemental heating was provided, implying that low temperatures are a limiting factor for plant growth. Growth effects were stronger when the Navel scion was grafted on Carrizo compared to Rubidoux, likely because of the higher dormancy of the latter rootstock. Night interruption did not affect scion budbreak or growth under any of the tested conditions. Preconditioning enhanced scion growth in some instances. The results suggest that the use of supplemental LED light to extend the day length may increase plant growth during the short winter days, but the effects are limited under low-temperature conditions. Full article

Pear decline (PD) phytoplasma populations were examined over one year in non-symptomatic pear trees with HW620 scions grafted onto three different rootstocks: OH×F87 (PD resistant), OH×F69 (PD susceptible), and Bartlett (PD susceptible). For all three rootstocks, populations were at a maximum during late summer for leaves and shoots, and reached their minimum in mid-winter for shoots and early spring for leaves. In contrast, roots exhibited maximum populations in mid-winter and minimum populations in mid-spring. For all tissue types, PD populations were consistently lowest in trees grafted onto OH×F87 rootstocks, intermediate in those on OH×F69, and highest on Bartlett rootstocks, demonstrating that the type of rootstock significantly impacts PD populations. While OH×F87 rootstocks had the lowest populations, they can still contain relatively high PD populations, particularly during periods with maximum populations. Future research could explore the development of even higher levels of PD resistance in pear rootstocks to reduce PD populations in both the rootstock and scion. Full article

In the Baltics, warming is expected to burden the growth of Norway spruce Picea abies, with weather anomalies/extremes having strong triggering effects, which can be mitigated by tree breeding. Within the region, breeding programmes have been aiming for productivity, yet being conservative, their sustainability depends on the adaptability of native genotypes, which is unclear. The adaptability of genotypes can be assessed through local adaptations and phenotypic plasticity, with the sensitivity of increment depicting the conformity of genotypes and environments. To assess the adaptability of native populations to anticipated climates, local genetic adaptation and phenotypic plasticity of the weather sensitivity of the radial increment were assessed by the methods of time series analysis and quantitative genetics based on three clonal trials (low-density single-tree plot plantations of grafted clones of native plus trees) representing the local climatic gradient in Latvia. The growth of trees was sensitive to the moisture availability in summer and the thermal regime in winter, yet coinciding anomalies in both were associated with abrupt changes in tree ring width. These environmental effects differed among the clones, indicating genetic controls over the sensitivity of increment, which, however, decreased under a warmer climate, suggesting a limited adaptability of local populations to warming. Still, the weather-growth relationships showed moderate phenotypic plasticity, suggesting some mid-term adaptability. Accordingly, supplementation of breeding populations via assisted gene transfer with the genotypes that are adapted to warmer and drier climates appears crucial. Full article

Minirhizotron tubes were installed to monitor root growth dynamics of mature Shiraz grapevines in a rootstock trial established in the hot climate Riverina region of New South Wales, Australia. The vertical root distribution and seasonal root growth dynamics of Shiraz on own-roots and Shiraz grafted on the rootstocks Ramsey, 140 Ruggeri and Schwarzmann was studied for five seasons across a seven-year period to a depth of 60 cm. New root production was significantly influenced by genotype, soil depth, season, growth stage and year. Soil moisture and soil temperature were monitored at 10, 30 and 60 cm in the last two seasons. Soil moisture at 30 cm and soil temperature at all three depths were significant predictors of root growth. New root numbers were significantly higher in 140 Ruggeri than the other rootstocks. To the depth studied, 140 Ruggeri roots were evenly distributed from the topsoil down, whereas the majority of roots of Schwarzmann and Shiraz were located at intermediate depths in the 10–40 cm ad 20–40 cm zones respectively, while Ramsey roots were found at 20 cm or below. Depending on genotype, root growth occurred across several phenological stages but tended to peak at flowering. In some years we observed root growth in early and late winter at rates exceeding that of autumn, and this was associated with warmer temperatures during this period. In general, the seasonal dynamics of root growth attributes were found to be influenced by abiotic factors, but mainly determined by genotype. The insights gained from this study can help us better understand the interplay between rootstock, environment, and management, and predict how different rootstock genotypes may perform under changing climatic conditions. Full article

In years with unfavorable weather, winter frost during the blossoming season can play a significant role in reducing fruit yield and impacting the profitability of cultivation. The mango Naomi cultivar Mangifera indica L. has a low canopy that is severely affected by the effects of frost stress. As a result of the canopy being exposed to physiological problems, vegetative development is significantly inhibited. The current investigation aimed to study the influence of spraying nitric oxide and fogging spray systems on Naomi mango trees grafted on ‘Succary’ rootstock under frost stress conditions. The treatments were as follows: nitric oxide (NO) 50 and 100 μM, fogging spray system, and control. In comparison to the control, the use of nitric oxide and a fogging system significantly improved the leaf area, photosynthesis pigments of the leaf, the membrane stability index, yield, and physical and chemical characteristics of the Naomi mango cultivar. For instance, the application of 50 μM NO, 100 μM NO, and the fogging spray system resulted in an increase in yield by 41.32, 106.12, and 121.43% during the 2020 season, and by 39.37, 101.30, and 124.68% during the 2021 season compared to the control, respectively. The fogging spray system and highest level of NO decreased electrolyte leakage, proline content, total phenolic content, catalase (CAT), peroxidases (POX), and polyphenol oxidase (PPO) enzyme activities in leaves. Furthermore, the number of damaged leaves per shoot was significantly reduced after the application of fogging spray systems and nitric oxide in comparison to the control. Regarding vegetative growth, our results indicated that the fogging spray system and spraying nitric oxide at 100 μM enhanced the leaf surface area compared to the control and other treatments. A similar trend was noticed regarding yield and fruit quality, whereas the best values were obtained when the fogging spray system using nitric oxide was sprayed at a concentration of 100 μM. The application of fogging spray systems and nitric oxide can improve the production and fruit quality of Naomi mango trees by reducing the effects of adverse frost stress conditions. Full article

The weather variations around the world are already having a profound impact on agricultural production. This impacts apple production and the quality of the product. Through agricultural precision, growers attempt to optimize both yield and fruit size and quality. Two experiments were conducted using field-grown “Gala” apple trees in Geneva, NY, USA, in 2021 and 2022. Mature apple trees (Malus × domestica Borkh. cv. Ultima “Gala”) grafted onto G.11 rootstock planted in 2015 were used for the experiment. Our goal was to establish a relationship between stem water potential (Ψ_trunk), which was continuously measured using microtensiometers, and the growth rate of apple fruits, measured continuously using dendrometers throughout the growing season. The second objective was to develop thresholds for Ψ_trunk to determine when to irrigate apple trees. The economic impacts of different irrigation regimes were evaluated. Three different water regimes were compared (full irrigation, rainfed and rain exclusion to induce water stress). Trees subjected the rain-exclusion treatment were not irrigated during the whole season, except in the spring (April and May; 126 mm in 2021 and 100 mm in 2022); that is, these trees did not receive water during June, July, August and half of September. Trees subjected to the rainfed treatment received only rainwater (515 mm in 2021 and 382 mm in 2022). The fully irrigated trees received rain but were also irrigated by drip irrigation (515 mm in 2021 and 565 mm in 2022). Moreover, all trees received the same amount of water out of season in autumn and winter (245 mm in 2021 and 283 mm in 2022). The microtensiometer sensors detected differences in Ψ_trunk among our treatments over the entire growing season. In both years, experimental trees with the same trunk cross-section area (TCSA) were selected (23–25 cm⁻² TCSA), and crop load was adjusted to 7 fruits·cm⁻² TCSA in 2021 and 8.5 fruits·cm⁻² TCSA in 2022. However, the irrigated trees showed the highest fruit growth rates and final fruit weight (157 g and 70 mm), followed by the rainfed only treatment (132 g and 66 mm), while the rain-exclusion treatment had the lowest fruit growth rate and final fruit size (107 g and 61 mm). The hourly fruit shrinking and swelling rate (mm·h⁻¹) measured with dendrometers and the hourly Ψ_trunk (bar) measured with microtensiometers were correlated. We developed a logistic model to correlate Ψ_trunk and fruit growth rate (g·h⁻¹), which suggested a critical value of −9.7 bars for Ψ_trunk, above which there were no negative effects on fruit growth rate due to water stress in the relatively humid conditions of New York State. A support vector machine model and a multiple regression model were developed to predict daytime hourly Ψ_trunk with radiation and VPD as input variables. Yield and fruit size were converted to crop value, which showed that managing water stress with irrigation during dry periods improved crop value in the humid climate of New York State. Full article

To evaluate the effects of donor ages on growth and stress resistance of 6-year-old seedlings propagated from 5-, 2000-, and 3000-year-old Platycladus orientalis donors with grafting, cutting, and seed sowing, growth indicators and physiological and transcriptomic analyses were performed in 6-year-old seedlings in winter. Results showed that basal stem diameters and plant heights of seedlings of the three propagation methods decreased with the age of the donors, and the sown seedlings were the thickest and tallest. The contents of soluble sugar, chlorophyll, and free fatty acid in apical leaves of the three propagation methods were negatively correlated with donor ages in winter, while the opposite was true for flavonoid and total phenolic. The contents of flavonoid, total phenolic, and free fatty acid in cutting seedlings were highest in the seedlings propagated in the three methods in winter. KEGG (Kyoto Encyclopedia of Genes and Genomes) enrichment analysis of differentially expressed genes showed phenylpropanoid biosynthesis and fatty acid metabolism pathways, and their expression levels were up-regulated in apical leaves from 6-year-old seedlings propagated from 3000-year-old P. orientalis donors. In addition, hub genes analysis presented that C4H, OMT1, CCR2, PAL, PRX52, ACP1, AtPDAT2, and FAD3 were up-regulated in cutting seedlings, and the gene expression levels decreased in seedlings propagated from 2000- and 3000-year-old donors. These findings demonstrate the resistance stability of cuttings of P. orientalis and provide insights into the regulatory mechanisms of seedlings of P. orientalis propagated from donors at different ages in different propagation methods against low-temperature stress. Full article

Electroimpedance spectroscopy technology can be used to accelerate the healing of complete trees and estimate the plant condition after grafting. This approach will allow sorting out low-vigor plants at the early stages of their development to save time and resources. Still, in some cases, the use of electrical impedance spectroscopy can be difficult due to the complexity of the equipment and special measurement conditions. In this paper, we attempt to overcome this limitation by suggesting a compact device developed in-house that is usable even in the field. Pear (Pyrus communis L.) Otradnenskaya was used as the object of this study. We assessed the treatment effect of the scion–rootstock interface with cold atmospheric plasma (CAP) and plasma-treated solution (PTS) on the survival of the grafts. The dependence of the impedance of the complete grafted tree on the signal frequency and the length of the measuring section was analyzed. It is shown that the treatment of the scion and rootstock with CAP and PTS promotes the fusion of scion and rootstock. The impedance value in the control was on average 24–35% higher than in plants treated with CAP and PTS, which indicates a better healing process of the grafting site. This can be an indication of better quality of the planting material which can be obtained much earlier than with the conventional approach (monitoring the plants in a nursery). Full article

Syrah decline, first identified in Southern France in the 1990s, has become a major concern in the global grape and wine industry. This disease mainly affects Syrah (Shiraz) grapevines. Characteristic symptoms include the bright and uniform reddening of leaves throughout the canopy in late summer or early fall; the appearance of abnormalities on the trunk, mainly at the graft union (swelling, pits, grooves, and necrosis); and a reduction in vine vigor, yield and berry quality. Diseased vines may die a few years after disease onset. Damages to the vine are even more pronounced in cool climate regions such as Ontario (Canada), where the affected vines are subjected to very cold and prolonged winters, leading to large numbers of vine deaths. Despite the extensive efforts of the global grape research community over the past few decades, the etiology of this disease remains unclear. In this study, we conducted extensive analyses of viruses in declining Syrah vines identified in commercial vineyards in the Niagara region (Ontario, Canada) through high-throughput sequencing, PCR, RT-PCR and the profiling of genetic variants of select viruses. Multiple viruses and viral strains, as well as three viroids, were identified. However, an unequivocal causal relationship cannot be established between Syrah decline and any of these viruses, although the possibility that certain virus or genetic variants, or both in combination, may contribute to the disease cannot be excluded. Gleaning all information that is available to date, we feel that the traditional approach and an insistence on finding a single cause for such a complex disorder in a woody perennial fruit crop involving grafting will prove to be futile. We hope that this study offers new conceptual perspectives on the etiology of this economically important but enigmatic disease complex that affects the global grape and wine industry. Full article

Cut roses are ornamental crops that are produced year-round, and the quality and yield of these cut flowers vary depending on the temperature and light intensity of the four seasons. Grafting improves productivity by increasing adaptability to negative environments, such as high temperature and low light intensity. The effectiveness of grafting depends on the type of the scion and rootstock. In order to confirm the effectiveness of stenting on roses, two varieties of cut roses (Rosa hybrida cv. Pink Beauty and Pink Shine) were grafted onto three rootstocks (R. multiflora Natal Briar, R. indica Major, and Rosa multiflora Hort. No. 1), which are widely used in cut rose, and the quality and yield of the cut flowers were investigated year-round according to the four seasons; then, principal component analysis (PCA) was performed. The Rosa hybrida cv. Pink Beauty (PB) used as the scion showed high yield and excellent growth in autumn when the light intensity was high and the temperature was low. The PB grafted onto the R. multiflora Natal Briar (NA) rootstock showed improved growth in spring, autumn and winter, excluding summer, and had the effect of lengthening the stem. The growth of PB grafted onto R. indica Major (RI) rootstock was also improved in spring, autumn, and winter, except summer, and in particular, the stem was lengthened and thickened. The rosa hybrida cv. Pink Shine (PS) was a variety whose yield of cut flowers increased in summer when the temperature was high. The PS grafted onto the three rootstocks gave a higher yield of cut flowers than the PS scion. The graft of PS/Natal Briar gave longer stems than the PS scion, and the graft of PS/Major gave thicker stems than the PS scion. PS grafted onto the Rosa multiflora Hort. No. 1 (N1) rootstock gave more petals than the PS scion. As such, cut roses grafted onto the Rosa canina cv. Natal brier (NA) improved the stem length, increasing the adaptability to relatively high temperatures, and the Rosa indica cv. Major (RI) improved the stem length and stem diameter, enhancing the adaptability to relatively low temperatures. Full article

With this research, we aimed to determine the impact of grafting and rootstock seed treated with Streptomyces griseus (MT210913) (S. griseus) or shikimic acid (SA) at a 60 ppm concentration on tomato (Solanum lycopersicum L.) production grown under low-temperature conditions. Two open-field trials were performed during both winter seasons of 2020 and 2021 at the Experimental Farm, Faculty of Agriculture, Cairo University, Giza, Egypt. A tomato cultivar (Peto 86) was used as a scion and two tomato phenotypes were employed as rootstocks (Solanum cheesmaniae L. (line LA 524) and GS hybrid), as well as self-grafted as a control. Effects of sub-optimal temperature on vegetative growth, yield, and fruit quality were tested. The results indicate that, under cold stress, rootstock seed priming, especially with S. griseus, enhanced plant growth, total yield, and fruit quality properties. GS hybrid rootstock was more effective than that of S. cheesmaniae rootstock in terms of mitigating the negative effect of cold stress. GS hybrid, inoculated with S. griseus, increased the total yield per plant by 10.5% and 5.7% in the first and second seasons, respectively. Higher levels of GA3 and mineral content were noticed in leaves that were grafted and treated with S. griseus compared to the control treatment. Additionally, the great enhancing effects of all anatomical features of tomato plants were recorded with GS hybrid rootstock, inoculated by S. griseus. These results prove that grafting on GS hybrid rootstock treated with S. griseus is a potential choice to alleviate the cold stress of commercial tomato varieties. Full article

Cut roses are grown throughout the four distinct seasons of spring, summer, autumn, and winter in Korea. Especially in the very hot or cold seasons of summer or winter, the temperature and light environments inside a greenhouse cause abiotic stress on the growth of horticultural crops. In a greenhouse where shade cultivation is performed in summer, the temperature is high and the light intensity is low, whereas in winter when shade cultivation is not performed, both temperature and light intensity are low. This experiment investigated the year-round growth and yield changes of cut roses grafted onto three rootstocks. The root activity of rootstocks was generally higher than that of the scion. The stomata of the grafted cut roses showed morphological changes according to the seasons. Compared with the scion, the stomata of grafted cut roses became smaller and their number increased in summer, whereas only the stomata size increased in winter. The grafted cut roses had characteristics of high photosynthetic efficiency such as photosynthesis rate, stomatal conductance, transpiration rate from rootstocks under harsh environmental conditions including temperature and light intensity, and thus the photosynthetic efficiency was higher than that of the scion. There was no significant change in the yield of grafted cut roses, but flower quality parameters such as the stem height, stem thickness, and weight of grafted cut roses were improved according to the rootstocks compared with those of the scion. In particular, in cut roses grafted with R. multiflora cv. Natal Briar and Rosa indica ‘Major’ rootstocks, the weight increased as the stem lengthened and thickened in spring, autumn, and winter. Therefore, grafting is effective in improving the quality of cut roses grown under abiotic stress caused by harsh temperature and light intensity conditions during winter. Full article

The description of a new method of winter grafting of sweet cherry varieties “Revna” is given. The novelty of the method lies in the use of a portable device for generating cold plasma, as well as a plasma-treated solution, developed by the team of authors. It has been established that exposure to cold plasma affects the growth length of “Revna” cherries by 17–28%, while an increase in the diameter of the root collar by 20–23% was observed. The electrical resistivity in the grafting zone after exposure to plasma or plasma-activated water decreased by an average of 14% compared to the control, which indicated a better fusion of the transport fibers of the rootstocks and scions. Full article

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”. Full article