Rootstock Genotypes Research Articles

Key Chemical Soil Parameters for the Assembly of Rhizosphere Bacteria Associated with Avocado Cv Hass Grafted on Landrace Rootstocks

Avocado cultivation holds significant economic importance in many countries, ranking Colombia as the fifth largest global producer. Particularly, the Hass cultivar plays a pivotal role in Colombia’s avocado industry, especially in the Department of Antioquia, the primary export region. This cultivar is grown under diverse soil and climate conditions and exhibits considerable genetic polymorphism due to the hybridization of varieties of agronomic significance, leading to a diverse array of landrace rootstocks. However, the role of soil conditions and rootstock genotype in structuring rhizosphere bacterial communities is still lacking. In addressing this knowledge gap, we investigated the influence of two soil conditions on the structure of rhizosphere bacterial communities associated with two landrace genotypes of Persea americana cv. Hass, utilizing 16S rRNA sequencing. Notably, no significant differences related to genotypes were observed. This study reports that the rhizosphere bacterial microbiome remains consistent across avocado landrace rootstocks, while variations in key parameters such as phosphorus, pH, Mg, and Ca drive distinct rhizosphere effects. Our results reveal that despite the soils having similar management, increases in these crucial parameters can lead to bacterial communities with lower alpha diversity and a more complex co-occurrence network. In addition, we found substantial variations in beta diversity, bacterial composition, and metagenome predictions between the two farms, underscoring the role of soil variables in shaping the bacterial microbiome. These findings provide valuable insights into the factors influencing the bacterial communities that may play a role in the health and productivity of crops with agro-industrial potential, such as Hass avocado.

Разработка природоподобной технологии размножения низкорослых подвоев косточковых культур в закрытом грунте

Abstract. The creation of technologies in accordance with the directions for the introduction of environmentally friendly, resource-saving developments into agriculture is relevant. Accelerated reproduction of planting material of the "basic" and "proven" categories is considered equally important, which requires optimization of reproduction by green cuttings. Green cutting allows to significantly quickly increase the yield of cuttings from one mother plant, reducing the area of the mother plantations by 4-5 times. Its advantage is the genetic uniformity of own-root plants, contributing to the elimination of plant infection with diseases and pests, ensuring a shorter growing period, successful combination with other stages of recovery: microclonal reproduction, reproduction by green grafting. In the protected ground conditions, studies were carried out (2019-2023) to isolate the most effective drug for the reproduction of healthy mother rootstock bushes for small-stone crops: AI 5 B, 3-20, AI-1.10-18, 3-107 (FSBSI NCFSCHVW breeding); VSL-2 (Crimean EBS breeding). The effect of the drugs was compared: plant growth regulators: Indolyl-3-butyric acid (IMC, SP), Phytactive Extraplus, CE; microbiological fertilizers: Sporex, Zh, Ultrex, Zh; Sporion, Zh, control (water). It was found that the treatment of BCI and the phytactive Extraplus reduced the period of appearance of primary roots by 4.5 and 5 days, depending on the rootstock. The largest percentage of rooted ones was obtained using the microbiological preparation Ultrex (3-47 % more than the control variant, depending on the rootstock genotype), also in this variant, due to its positive effect on root formation of more than 2 mm, increased stress resistance, more standard planting material was obtained by 90 % relative to the control ones. Key words: basic mother plantings, green cuttings, plant growth regulators, preparations based on microorganisms and their waste products, the percentage of yield of standard rootstocks for sweet cherries and cherries.

Hyperspectral imaging and artificial intelligence enhance remote phenotyping of grapevine rootstock influence on whole vine photosynthesis.

Rootstocks are gaining importance in viticulture as a strategy to combat abiotic challenges, as well as enhancing scion physiology. Photosynthetic parameters such as maximum rate of carboxylation of RuBP (Vcmax) and the maximum rate of electron transport driving RuBP regeneration (Jmax) have been identified as ideal targets for potential influence by rootstock and breeding. However, leaf specific direct measurement of these photosynthetic parameters is time consuming, limiting the information scope and the number of individuals that can be screened. This study aims to overcome these limitations by employing hyperspectral imaging combined with artificial intelligence (AI) to predict these key photosynthetic traits at the canopy level. Hyperspectral imaging captures detailed optical properties across a broad range of wavelengths (400 to 1000 nm), enabling use of all wavelengths in a comprehensive analysis of the entire vine's photosynthetic performance (Vcmax and Jmax). Artificial intelligence-based prediction models that blend the strength of deep learning and machine learning were developed using two growing seasons data measured post-solstice at 15 h, 14 h, 13 h and 12 h daylengths for Vitis hybrid 'Marquette' grafted to five commercial rootstocks and 'Marquette' grafted to 'Marquette'. Significant differences in photosynthetic efficiency (Vcmax and Jmax) were noted for both direct and indirect measurements for the six rootstocks, indicating that rootstock genotype and daylength have a significant influence on scion photosynthesis. Evaluation of multiple feature-extraction algorithms indicated the proposed Vitis base model incorporating a 1D-Convolutional neural Network (CNN) had the best prediction performance with a R2 of 0.60 for Vcmax and Jmax. Inclusion of weather and chlorophyll parameters slightly improved model performance for both photosynthetic parameters. Integrating AI with hyperspectral remote phenotyping provides potential for high-throughput whole vine assessment of photosynthetic performance and selection of rootstock genotypes that confer improved photosynthetic performance potential in the scion.

Soil Traits and Grapevine Rootstock Genotypes Modulate Arbuscular Mycorrhizal Rate and Species in a Mediterranean Environment

The soil microbiota is a key component of agroecosystems, and understanding its traits is crucial for effective agronomic management. Among beneficial microorganisms, arbuscular mycorrhizal fungi (AMFs) are mutually associated with grapevine (Vitis vinifera L.), enhancing the ability of this cropping system to adapt to soil conditions and bolstering its resistance and resilience against abiotic stresses, particularly drought, by promoting root growth and enhancing the roots’ absorption surface. The objective of this on-field study was to determine AMF species richness and diversity along with their relation to soil chemical, physical, and biological characteristics in two adjacent organic vineyards in Central Italy. The two tested vineyards of the autochthonous cv. Aleatico differed by the presence of grafted (Vitis berlandieri × V. riparia rootstock; AL-420) or own-rooted (ungrafted V. vinifera L.; AL-ORV) vines. To this aim, soil and root samples were collected and geo-referenced. Analysis of the AMF species colonizing roots of both AL-ORV and AL-420 revealed the presence of four species: Scutellospora alterata, Paraglomus laccatum, Acaulospora laevis, and A. baetica, with S. alterata being the most frequent. Mycorrhization parameters were higher in the roots of grafted plants compared to ungrafted ones. A high beta-glucosidase (BG):N-acetylglusosaminidase (NAG) ratio in two tested vineyards indicated that microbes utilized more cellulose than chitin and peptidoglycan as dominant C resources. A negative correlation between mycorrhization rate (MyCP) and BG was observed, likely because AMFs form mutualistic relationships with plants, depending on the host plant for carbon. Results revealed a positive correlation between the degree of mycorrhizal association and the species involved, with the presence of copper and nickel among metals. Negative correlations were found concerning soil clay content along with beta-glucosidase. In conclusion, the grapevine root system was characterized by a differential symbiotic relationship with AMF species, whose development is influenced by the root genotype, soil texture, and biochemistry. Specifically, the increased frequency of AMFs in relation to copper content strengthens the evidence of their role in maintaining a vine’s production capacity in the event of soil contamination by this element.

Identifying Grapevine Rootstocks Tolerant to Copper Excess

The aim of the current study is to identify grapevine rootstocks with the potential to tolerate excessive Cu concentrations. Four grapevine rootstock genotypes were tested: Paulsen 1103, IAC 572, SO4 and Isabel. The plants were cultivated in nutrition solution added to the following treatments: 0.3 µM Cu and 80 µM Cu. Growth, nutrient concentration in tissue and the physiological and biochemical parameters were assessed. Rootstocks showed different growth responses to Cu excess in the solution. SO4, IAC 572 and Isabel markedly reduced growth under Cu excess compared to plants in the control solution, whereas genotype Paulsen 1103 showed a less pronounced effect. The root system of all genotypes presented a Cu increase under a high Cu concentration, as well as higher POD activity and H2O2 concentration than the control. Isabel presented the greatest sensitivity to Cu excess, as shown by leaf wilting and yellowing. Paulsen 1103 rootstock presented smaller changes in the observed parameters in the high Cu concentration solution than in the control solution. Our results indicate that Paulsen 1103 is the most tolerant to Cu excess, whereas Isabel is the most sensitive. There are natural genetic variations in tolerance to this abiotic stress that typically affect grapevine plants.

Characterization of Citrus × Poncirus Embryo Rescued Hybrids as Rootstock Candidate using Morphological Markers

In generally, there are both of nucellar and zygotic embryos in the citrus seeds after cross breeding. Since genetic variations are very important for success of plant breeding, morphological traits of individuals are evaluated to identify diversity. The present study aimed to characterization of citrus hybrids for new rootstock genotypes based on its morphological characters at seedling stage. A total of 335 putative interspecies hybrids, derived from 3 crosses [Common sour orange (Citrus aurantium L.) × Troyer citrange (Citrus sinensis L. × Poncirus trifoliata L.), Common mandarin (Citrus deliciosa Ten.) × Troyer citrange (Citrus sinensis L. × Poncirus trifoliata L.) and King mandarin (Citrus nobilis L.) × Carrizo citrange (Citrus sinensis L. × Poncirus trifoliata L.)], were observed by their plant morphology. The eight qualitative and five quantitative characteristics of hybrid plants such as seedling growth, leaf and thorniness characteristics were evaluated. The average plant height of the population was found between 70.2 cm and 133.2 cm. The average stem diameter varied between 5.9 mm and 8.0 mm. Hybrid seedlings were separated on the basis of dominant trifoliate leaf marker. There was wide diversity among the accessions with respect to quantitative leaf characters. In terms of leaf division, 268 genotypes have bifoliate and 67 were trifoliate in all combinations, and many intermediate forms were also observed. In addition 66 of the genotypes were thornless while 269 of the genotypes were thorny. The genotype No. 4, has been assessed as triploid, from Common mandarin × Troyer citrange combination, has the longest and dense spines. Morphological markers data were analysed by clustering method to compare similarities of hybrids. The dissimilarity index was observed between 0.004 and 17.318 within three hybridization combinations. The hybrids obtained at 110 days after pollination were more distant relative to each other all hybridization combination.

The rootstock modifies the arbuscular mycorrhizal community of the root system, while the influence of the scion is limited in grapevines.

Understanding the effects of grapevine rootstock and scion genotypes on arbuscular mycorrhizal fungi (AMF), as well as the roles of these fungi in plant development, could provide new avenues for adapting viticulture to climate change and reducing agrochemical inputs. The root colonization of 10 rootstock/scion combinations was studied using microscopy and metabarcoding approaches and linked to plant development phenotypes. The AMF communities were analysed using 18S rRNA gene sequencing. The 28S rRNA gene was also sequenced for some combinations to evaluate whether the method changed the results. Root colonization indexes measured by microscopy were not significantly different between genotypes. Metabarcoding analyses showed an effect of the rootstock genotype on the β-diversity and the enrichment of several taxa with both target genes, as well as an effect on the Chao1 index with the 18S rRNA gene. We confirm that rootstocks recruit different AMF communities when subjected to the same pedoclimatic conditions, while the scion has little or no effect. Significant correlations were observed between AMF community composition and grapevine development, suggesting that AMF have a positive effect on plant growth. Given these results, it will be important to define consensus methods for studying the role of these beneficial micro-organisms in vineyards.

Response of selected scion and rootstock grape (<i>Vitis </i>spp.) genotypes to induced drought stress

Climate change is expected to elevate drought frequency, straining agricultural freshwater resources. Developing drought-tolerant grapevine varieties is crucial. This study examined grape scion and rootstock genotypes under well-watered (WW) and induced-drought (ID) conditions. ID treatment reduced vine length by 11.34-35.15%, with Vitis parviflora, 110R, and Male Hybrid rootstocks showing superior growth. Root length increased under ID, indicating an adaptive moisture-seeking response. The ID treatment led to substantial reduction in leaf count and average leaf area, especially in Flame Seedless (27.71 and 19.07 cm2, respectively). Drought stress elevated chlorophyll a:b ratio, affecting chlorophyll degradation in different genotypes. Significant variations were observed in leaf and root iron (Fe) and zinc (Zn) contents. Enzyme activities particularly peroxidase and polyphenol oxidase especially rose under drought, particularly in V. parviflora (3.39 μM guaiacol min-1 mg-1 protein and 1.33EU/ml/min respectively) likely to be contributing in drought tolerance mechanism. Principal component analysis (PCA) highlighted impact of traits on genotypes, emphasizing V. parviflora, Male Hybrid and Pusa Navrang as superior drought stress tolerant genotypes. Genotype clustering confirmed distinct groupings, while, correlation analysis unveiled intricate trait interactions.

Maritime Pine Rootstock Genotype Modulates Gene Expression Associated with Stress Tolerance in Grafted Stems.

Climate change-induced hazards, such as drought, threaten forest resilience, particularly in vulnerable regions such as the Mediterranean Basin. Maritime pine (Pinus pinaster Aiton), a model species in Western Europe, plays a crucial role in the Mediterranean forest due to its genetic diversity and ecological plasticity. This study characterizes transcriptional profiles of scion and rootstock stems of four P. pinaster graft combinations grown under well-watered conditions. Our grafting scheme combined drought-sensitive and drought-tolerant genotypes for scions (GAL1056: drought-sensitive scion; and Oria6: drought-tolerant scion) and rootstocks (R1S: drought-sensitive rootstock; and R18T: drought-tolerant rootstock). Transcriptomic analysis revealed expression patterns shaped by genotype provenance and graft combination. The accumulation of differentially expressed genes (DEGs) encoding proteins, involved in defense mechanisms and pathogen recognition, was higher in drought-sensitive scion stems and also increased when grafted onto drought-sensitive rootstocks. DEGs involved in drought tolerance mechanisms were identified in drought-tolerant genotypes as well as in drought-sensitive scions grafted onto drought-tolerant rootstocks, suggesting their establishment prior to drought. These mechanisms were associated with ABA metabolism and signaling. They were also involved in the activation of the ROS-scavenging pathways, which included the regulation of flavonoid and terpenoid metabolisms. Our results reveal DEGs potentially associated with the conifer response to drought and point out differences in drought tolerance strategies. These findings suggest genetic trade-offs between pine growth and defense, which could be relevant in selecting more drought-tolerant Pinus pinaster trees.

Effect of Rootstock Genotype and Arbuscular Mycorrhizal Fungal (AMF) Species on Early Colonization of Apple.

The effect of plant cultivar on the degree of mycorrhization and the benefits mediated by arbuscular mycorrhizal fungi (AMF) have been documented in many crops. In apple, a wide variety of rootstocks are commercially available; however, it is not clear whether some rootstock genotypes are more susceptible to mycorrhization than others and/or whether AMF species identity influences rootstock compatibility. This study addresses these questions by directly testing the ability/efficacy of four different AMF species (Rhizophagus irregularis, Septoglomus deserticola, Claroideoglomus claroideum or Claroideoglomus etunicatum) to colonize a variety of commercially available Geneva apple rootstock genotypes (G.11, G.41, G.210, G.969, and G.890). Briefly, micropropagated plantlets were inoculated with individual species of AMF or were not inoculated. The effects of the rootstock genotype/AMF interaction on mycorrhization, plant growth, and/or leaf nutrient concentrations were assessed. We found that both rootstock genotype and the identity of the AMF are significant sources of variation affecting the percentage of colonization. However, these factors largely operate independently in terms of the extent of root colonization. Among the AMF tested, C. etunicatum and R. irregularis represented the most compatible fungal partners, regardless of apple rootstock genotype. Among the rootstocks tested, semi-dwarfing rootstocks appeared to have an advantage over dwarfing rootstocks in regard to establishing and maintaining associations with AMF. Nutrient uptake and plant growth outcomes were also influenced in a rootstock genotype/AMF species-specific manner. Our findings suggest that matching host genetics with compatible AMF species has the potential to enhance agricultural practices in nursery and orchard systems.

Both the scion and rootstock of grafted grapevines influence the rhizosphere and root endophyte microbiomes, but rootstocks have a greater impact

BackgroundSoil microorganisms play an extensive role in the biogeochemical cycles providing the nutrients necessary for plant growth. Root-associated bacteria and fungi, originated from soil, are also known to influence host health. In response to environmental stresses, the plant roots exude specific molecules influencing the composition and functioning of the rhizospheric and root microbiomes. This response is host genotype-dependent and is affected by the soil microbiological and chemical properties. It is essential to unravel the influence of grapevine rootstock and scion genotypes on the composition of this microbiome, and to investigate this relationship with plant growth and adaptation to its environment. Here, the composition and the predicted functions of the microbiome of the root system were studied using metabarcoding on ten grapevine scion-rootstock combinations, in addition to plant growth and nutrition measurements.ResultsThe rootstock genotype significantly influenced the diversity and the structure of the bacterial and fungal microbiome, as well as its predicted functioning in rhizosphere and root compartments when grafted with the same scion cultivar. Based on β-diversity analyses, 1103P rootstock showed distinct bacterial and fungal communities compared to the five others (RGM, SO4, 41B, 3309 C and Nemadex). The influence of the scion genotype was more variable depending on the community and the investigated compartment. Its contribution was primarily observed on the β-diversity measured for bacteria and fungi in both root system compartments, as well as for the arbuscular mycorrhizal fungi (AMF) in the rhizosphere. Significant correlations were established between microbial variables and the plant phenotype, as well as with the plant mineral status measured in the petioles and the roots.ConclusionThese results shed light on the capacity of grapevine rootstock and scion genotypes to recruit different functional communities of microorganisms, which affect host growth and adaptation to the environment. Selecting rootstocks capable of associating with positive symbiotic microorganisms is an adaptation tool that can facilitate the move towards sustainable viticulture and help cope with environmental constraints.

Optimization of Rhizobium rhizogenes-mediated transformation, regeneration and characterization of Malus domesticaBorkh. Ri lines

This study explored the establishment and optimization of Ri (root inducing) technology for apple breeding, using the bacterium Rhizobium rhizogenes to obtain Ri lines with compact shoots and stronger root systems. The transformation and shoot regeneration for Malus domestica cultivars was studied in detail. Various R. rhizogenes strains, scion and rootstock genotypes, explant types, wounding methods and explant orientations were tested for hairy root induction. Most of the 16 tested strains, especially those with plasmid type III, induced hairy roots in the rootstock genotype ‘M26’. Although apple genotypes differed in response, in most of them roots were successfully induced using strains ATCC 15834, LMG 63 and LMG 150, with leaf blades outperforming petioles as explants. Wounding by scratching or sonication further improved transformation efficiency, as did placing leaf blades with their abaxial side upward on root induction medium. The majority (94%) of roots formed in one transformation experiment were tested PCR-positive for at least one T-DNA gene. Shoot regeneration experiments investigated salt concentrations, gelling agents, cytokinin types, concentrations, and a resting period on hormone-free medium. Shoot regeneration was highly genotype-dependent varying between 0 and 83%, whereas only minor, non-significant effects were observed for the treatments tested. Copy numbers of T-DNA genes were estimated using digital PCR for the first time in apple Ri lines. In the greenhouse, two Ri lines showed compact shoots and shorter leaves, but no enhanced root system. The improved protocol provides a valuable tool for breeders and scientists to obtain and further use Ri lines.

Rootstocks for Grapevines Now and into the Future: Selection of Rootstocks Based on Drought Tolerance, Soil Nutrient Availability, and Soil pH

Rootstocks are used in viticulture to manage plant pests and diseases, particularly phylloxera and root-knot nematodes, and to improve grape and wine production. A wide range of rootstocks are commercially available, making selecting the optimal rootstock a difficult decision. In particular, distinct rootstock genotypes may manifest varying degrees of tolerance or resistance to abiotic stress, necessitating meticulous consideration during the rootstock selection process. This article reviews characteristics of various commercial rootstocks, as well as rootstocks being developed in recent years. This review further discusses responses of rootstocks to drought, soil nutrients, and soil pH. This review mainly focuses on influence of rootstocks on physiology characteristics of grafted scions rather than berry yield and quality. The breadth of this review benefits both researchers and practitioners by providing comprehensive summery of rootstocks to inform selection and to guide future research.

РАЗРАБОТКА ПРИЕМОВ УПРАВЛЕНИЯ УСТОЙЧИВОСТЬЮ ПЛОДОВЫХ ЦЕНОЗОВ С ИСПОЛЬЗОВАНИЕМ ПЕРСПЕКТИВНЫХ БИОЛОГИЗИРОВАННЫХ МЕТОДОВ

The results of 2023 research on the development of methods for managing the stability of fruit agrocenoses with rational land use are presented. The objects of research are orchard agrobiocenoses under various cultivation conditions. The work used methodological approaches and original techniques developed by the research team. Methods and elements of technologies for increasing the resistance of fruit agrocenoses to a complex of factors with biologized approaches for controlling the development of pathogens and pests, rational formation of the crowns of fruit crops of domestic varieties against the background of the application of biostimulants, techniques for rationing high-quality fruit yield, optimized approaches for optimizing plant nutrition and reproducing soil fertility in biocenotic and molecular levels were developed. The obtained results of scientific research of a fundamental and applied nature are associated with the identification of patterns and disclosure of mechanisms for the formation of the productivity of fruit crops in changing cultivation conditions and create a methodological basis for the development of new elements of technologies for managing the productivity of orchard cenoses, systems for monitoring the resource potential of soils to provide the population with quality products while preserving the environment. New knowledge about the patterns of influence of rootstock genotype on the realization of the production potential of various scion-rootstock combinations of the genus Malus Mill. under conditions of different planting densities, will allow, through the use of the most productive scion-rootstock combinations, to significantly increase the productivity of plantings, make the most efficient use of the garden area, and significantly accelerate the onset of marketable fruiting. New knowledge about the patterns of influence of certain limiting parameters of the soil cover on the condition and productivity of scion-rootstock combinations of fruit crops will be used to develop optimal parameters for assessing the horticultural suitability of soils. The identified features of frost resistance of various pear varieties in terms of the degree of stability of their flower buds under changing weather conditions in different phases of the winter-spring period are the basis for optimizing the placement of pear crops in the North Caucasus zone. Key words: ORCHARD CENOSES, ENVIRONMENTAL STRESS, CHANGES IN WEATHER CONDITIONS, TRANSFORMATION OF SOIL PARAMETERS, SCION-ROOTSTOCK COMBINATIONS, DOMESTIC APPLE VARIETIES, FROST RESISTANCE OF PEAR VARIETIES, NUTRITION OPTIMIZATION, PATHOGENS AND PEST CONTROL

Grafting Bell Pepper onto Local Genotypes of Capsicum spp. as Rootstocks to Alleviate Bacterial Wilt and Root-Knot Nematodes under Protected Cultivation

In soil-based protected cultivation, the prevalence of certain diseases like bacterial wilt and nematodes in the bell pepper plant due to its successive cropping pose a threat for maximizing productivity. Considering the potential of grafting to alleviate various biotic and abiotic stresses, often relying on rootstock’s capability, we explored the potential of diverse local genotypes of Capsicum spp. to utilize as rootstocks. In this research, we assessed the performance of a commercial bell pepper cv. Massilia F1, grafted onto twenty-five rootstocks along with non-grafted and self-grafted Massilia plants under artificial inoculation conditions of bacterial wilt (Ralstonia solanacearum) and nematodes (Meloidogyne incognita) in a plastic greenhouse. The response of rootstock grafting was determined by assessing disease incidences and their effect on plants growth, yield, and physiology, as well as their efficiency in nutrient accumulation. The grafted plants exhibited varied responses to diseases depending on rootstock genotypes. Notably, Massilia grafted onto the CRS-8 and CRS-1 rootstocks exhibited high bacterial wilt resistance by showing lower percent disease incidence (PDI) (22.22 and 27.78 percent, respectively). Others, like CRS-11, CRS-12, CRS-13, CRS-21, and CRS-24, showed moderate resistance (PDI ranging from 33.33 to 38.89 percent, respectively). The self-grafted and non-grafted plants were highly susceptible and recorded complete mortality by the end of the experiment. All of the grafted plants exhibited promising resistance against nematode infestation compared to non-grafted and self-grafted plants with 26.17 and 8.67 percent root galls, respectively. The susceptible plants had lower shoot and root dry weights, while the resistant graft combinations had comparatively higher biomass. Importantly, grafting induced earliness in flowering and provided higher yields, especially in graft combinations involving the CRS-15, CRS-11, and CRS-8 rootstocks. These graft combinations exhibited significantly higher yields over the non-grafted and self-grafted plants. The plant yield was positively associated with plant height, number of leaves, fresh and dry weight of roots, number of fruits per plant, and average fruit weight, but negatively related to bacterial wilt and root-knot nematode incidences. The increased level of antioxidant enzymes such as polyphenol oxidase (PPO), phenylalanine ammonia lyase (PAL), and peroxidase (POD) and the higher total chlorophyll content in the resistant grafted plants indicates their better ability to cope with diseases at the cellular level. This study highlights the robust performance of certain rootstocks from Capsicum annuum (CRS-1, CRS-2, CRS-11, CRS-15) and Capsicum frutescens (CRS-8, CRS-13, CRS-22) species across multiple measured parameters. Grafting emerges as a sustainable solution for bell pepper production in bacterial wilt- and nematode-infested soil under plastic greenhouses.

Rootstock vigor dictates the canopy light environment that regulates metabolite profile and internal fruit quality development in peach

Five rootstock cultivars of differing vigor: vigorous (‘Atlas™’ and ‘Bright's Hybrid® 5’), standard (‘Krymsk® 86’ and ‘Lovell’) and dwarfing (‘Krymsk® 1’) grafted with ‘Redhaven’ as the scion were studied for their impact on productivity, mid-canopy photosynthetic active radiation transmission (i.e., light availability) and internal fruit quality. Αverage yield (kg per tree) and fruit count increased significantly with increasing vigor (trunk cross sectional area, TCSA). Α detailed peach fruit quality analysis on fruit of equal maturity (based on the index of absorbance difference, IAD) coming from trees with equal crop load (no. of fruit cm−2 of TCSA) characterized the direct impact of rootstock vigor on peach internal quality [dry matter content (DMC) and soluble solids concentration (SSC)]. DMC and SSC increased significantly with decreasing vigor and increasing light availability, potentially due to reduced intra-tree shading and better light distribution within the canopy. Physiologically characterized peach fruit mesocarp was further analyzed by non-targeted metabolite profiling using gas chromatography mass spectrometry (GC-MS). Metabolite distribution was associated with rootstock vigor class, mid-canopy light availability and fruit quality characteristics. Fructose, glucose, sorbose, neochlorogenic and quinic acids, catechin and sorbitol were associated with high light environments and enhanced quality traits, while sucrose, butanoic and malic acids related to low light conditions and inferior fruit quality. These outcomes show that while rootstock genotype and vigor are influencing peach tree productivity and yield, their effect on manipulating the light environment within the canopy also plays a significant role in fruit quality development.

Development of a preliminary extraction protocol for phenol compounds during table grape grafting formation

The development of rootstocks that are less sensitive to abiotic and biotic stresses can help mitigate the negative effects of climate change on crop productivity, soil health, and water use. Though, the phenomenon of graft incompatibility is a significant limitation to the spread of new rootstock genotypes. Numerous studies have focused on this issue, highlighting the role of certain phenolic molecules as predictive markers of incompatibility. Given the lack of specific research on table grape, , this study proposes a protocol for the extraction of polyphenols from its woody tissues, which is a fundamental prerequisite for further analysis on secondary metabolites involved in graft incompatibility. The proposed eco-friendly method coupled a traditional maceration using solvent with a green technique utilizing an ultrasound-assisted extractor. The following parameters were compared: (1) sample weight (0.1 g, 0.5 g, and 1 g), (2) time of ultrasound-assisted extraction (10 min, 20 min, and 30 min), and (3) solvent volume for maceration (10 mL, 15 mL, and 20 mL). Four phenol classes were considered based on previous works on <i>Vitis</i> spp.: cinnamic acids, flavonols, benzoic acids, and catechins. The characterization of polyphenolic biomarkers was carried out via HPLC. 1 g of plant material, 30 minutes of sonification, and 20 mL of organic solvent was the combination of factors that resulted in the most efficient fingerprint, both quantitatively (267.68 ± 3.91 mg/100 g fresh weight [FW]) and qualitatively, with the four classes analyzed significantly represented. This is the first work to come up with an extraction protocol for phenol compounds in table grape woody tissue based on both ecological and routine techniques.

Horticultural performance and huanglongbing impact on rainfed Valencia sweet orange grafted onto 16 rootstock genotypes

Horticultural performance and huanglongbing impact on rainfed Valencia sweet orange grafted onto 16 rootstock genotypes

The Influence of Dwarfing Interstock on Biometric Growth Parameters of Apple

Apple trees grown on seedling rootstock often develop into large and vigorous trees making its management difficult. By using vigorous rootstocks only few trees can be accommodated per hectare making the productivity less profitable. Several dwarfing rootstocks of apple are available which need support system and incur heavy investment during orchard establishment. It would be ideal to obtain a tree with very good root system, to avoid the need for supporting systems and also with a low height, which can be achieved using the interstem. Therefore, in the present investigation M9 clonal interstem comprised of 2,4,6 and 8inches length were grafted between seedling rootstock and scion of two cultivars i.e., Red Delicious and American Apirouge which are most common and predominant cultivars in orchards of Kashmir. The average sapling height was to the tune of 38.85cm and 41.01 cm in Red Delicious and American Apirouge during first year of study. There was a progressive increase in the height of plant with decreasing interstem length. In both the apple cultivars stem diameter increased with decrease in interstem length but was lower than control during both the years of study, The rootstock influences the biometric parameters of the grafted trees. The results showed that increased interstem length significantly decreased sapling height and growth whereas, days taken to sprouting and survival per cent were non significant. Thus, it appeared as if the dwarfing rootstock genotype used as an inter-stem functioned as a kind of physical restriction to water movement and probably reduced the hydraulic conductance of the whole tree.

Characterization of Almond Scion/Rootstock Communication in Cultivar and Rootstock Tissues through an RNA-Seq Approach.

The rootstock genotype plays a crucial role in determining various aspects of scion development, including the scion three-dimensional structure, or tree architecture. Consequently, rootstock choice is a pivotal factor in the establishment of new almond (Prunus amygdalus (L.) Batsch, syn P. dulcis (Mill.)) intensive planting systems, demanding cultivars that can adapt to distinct requirements of vigor and shape. Nevertheless, considering the capacity of the rootstock genotype to influence scion development, it is likely that the scion genotype reciprocally affects rootstock performance. In the context of this study, we conducted a transcriptomic analysis of the scion/rootstock interaction in young almond trees, with a specific focus on elucidating the scion impact on the rootstock molecular response. Two commercial almond cultivars were grafted onto two hybrid rootstocks, thereby generating four distinct combinations. Through RNA-Seq analysis, we discerned that indeed, the scion genotype exerts an influence on the rootstock expression profile. This influence manifests through the modulation of genes associated with hormonal regulation, cell division, root development, and light signaling. This intricate interplay between scion and rootstock communication plays a pivotal role in the development of both scion and rootstock, underscoring the critical importance of a correct choice when establishing new almond orchards.