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Pink pine nut, a dried fruit, is produced by a Mexican pine species. However, unlike other nuts, the lack of management practices and the absence of grafting techniques hinder its production. This work evaluated the behavior and growth of Pinus cembroides (PC) and P. orizabensis (PO) grafted onto four rootstocks. Two trials were conducted in April and June 2020 with PC and PO scions. The rootstocks used were PC, P. patula (PP), P. teocote (PT), and P. greggii var. australis (PG). The variables evaluated were engraftment (%), height increase (HI), scion diameter (SD), rootstock diameter (RD), scion-rootstock ratio (SRR), survival (%), and number of shoots (NS). No statistical analyses were performed for engraftment, survival, and SRR; for HI, SD, and RD, a mean comparison was performed (Tukey ≤ 0.05), and NB was analyzed by Poisson regression. In the first trial, successful engraftment varied from 45.5 to 100%; in the second trial, the range was from 73.3 to 100%. In terms of height, the PO/PC combination reached 21.14 cm, and the PC/PC combination measured 17.69 cm for April and June. The average survival was 60.42% for the first experiment; for the second experiment, only two combinations (PC/PG and PC/PC) survived with an average of 75.85%. Thus, it is possible to implement the grafting technique in pine nut species. This is the first work reporting successful grafting for this species, focusing on seed production. [ABSTRACT FROM AUTHOR]

Pistacia genus is botanically classified in the Sapindales order and the Anacardiaceae family, and the member of this genus P. eurycarpa is used as a rootstock for pistachio. Due to its rich oil content, various soaps are produced from the green peels of P. eurycarpa nuts and are used in the cosmetic industry as soap. In the current study, we aimed to release the complete chloroplast genome of P. eurycarpa to detect the relationship of the members of the Sapindales and also Pistacia genus. The length of the chloroplast genome of P. eurycarpa was identified 160,693 (bp) and consisted of the distinct parts of the genomic fragments such as LSC, SSC, and IR regions. The length of the LSC was 88,410 (bp), and SSC genomic range represented a total of 19,087 (bp). Inverted regions length was 26,598 (bp). A total of 125 genes were determined within the whole chloroplast genome of P. eurycarpa. The number of simple sequence repeats (SSRs) in the chloroplast genome was computed as 74. Three main clusters defined the dendrogram of all accessions. The closest pairs of species were identified among the P. eurycarpa and P. vera species. The farthest genetic relationship was calculated among the members of the Sapindales species Mangifera indica and the Fagales species Castanea mollissima. The sequences of the chloroplast genome of P. eurycarpa species can be evaluated for the construction of the basis of the complete evolution of the order, genera, and the development of the SSRs for species-specific markers for revealing the evolution of Pistacia species for future breeding research. [ABSTRACT FROM AUTHOR]

Main Conclusion: The dwarfing mechanism in apple clonal rootstocks is driven by complex interactions between anatomical, hormonal, genetic, and phenolic factors, offering potential for advanced genetic manipulation to optimize tree size and enhance orchard productivity. The widespread adoption of dwarfing rootstocks is pivotal to modern commercial apple (Malus × domestica Borkh) orchards due to their ability to control tree size, shorten the juvenile period, and enhance reproductive growth and overall productivity. The underlying mechanisms of rootstock-induced dwarfism are multifaceted and involve interactions between phenotypic, anatomical, genetic, and phytohormonal factors. This review consolidates current understanding, highlighting the importance of auxin (IAA), cytokinins (CKs), gibberellins (GAs), and abscisic acid (ABA) in mediating growth suppression through impaired transport and hormone signaling. The phenotypic impacts, including reduced root growth, shorter sylleptic shoots, and higher floral bud densities, are discussed alongside genetic loci such as Dw1, Dw2, and Dw3, and the influence of key genes/TFs like MdWRKY9, RGL, and PIN. Anatomically, dwarf rootstocks exhibit a higher bark-to-wood ratio and restricted hydraulic conductivity, which contribute to reduced scion vigour. Furthermore, the accumulation of phenolic compounds in the graft union of dwarfing rootstocks further modulates the growth inhibition. These insights lay the groundwork for advanced molecular breeding strategies, incorporating gene-editing technologies to improve dwarf rootstock development, providing avenues for enhanced orchard management and apple productivity. [ABSTRACT FROM AUTHOR]

Drought stress is one of the most important limitations in the production of agricultural products and especially horticulture in different parts of the world and Iran. The climate changes that have happened in the last few years, it is possible to provide sustainable production of grapes in water stress conditions by examining and selecting cultivars that tolerate to drought stress. For this purpose, an experiment from 2018 to 2022 in the form of split plots in the form of randomized complete blocks with 3 replications in garden conditions to investigate the effect of changes in soil water potential on the morphological, physiological and biochemical characteristics of grafted cuttings on cultivar traits Tolerant to sensitive 7 grape (Vitis vinifera L.) cultivars were carried out. The treatments included 7 selected grape varieties (‘Bidaneh Ghermez’, ‘Bidaneh Sefid’, ‘Rashe’, ‘Sahani’, ‘Kare Royeh’, ‘Moulai’, and ‘Chafte’) as the base and red quince cultivar as scion and three levels of drought stress including humidity. Agricultural (control), 75% (moderate stress) and 55% (severe stress) were based on agricultural moisture discharge. The results showed that with more severe water stress, the amount of proline, ABA, activity of catalase and peroxidase, the expression of CBF4, NCED3, and DHN1 genes increased, as well as the amount of total chlorophyll were decreased. In this experiment, the highest proline, abscisic acid, catalase, peroxidase, NCED3, CBF4 and DHN1 gene expression were observed in this experiment under severe stress treatment. In general, ‘Bidaneh Ghermez’ cultivar grafted on the rootstocks of ‘Chafte’, ‘Moulai’ and ‘Kare Royeh’ had a higher potential for tolerance to drought stress than other grafted combinations tested in most of the traits. [ABSTRACT FROM AUTHOR]

A greater genetic diversity is essential for disease resistance in particular, and intergeneric hybridization makes this possible. The genus Cydomalus (syn: Cydolus), which is frequently used as rootstock, was derived from intergeneric hybridization between Cydonia oblonga Mill. and Malus domestica Borkh in Moldova and Bulgaria. It is known that hybrids from this genus exhibit quince and/or apple characteristics and some of them have been identified with reddish fruit skin color in Türkiye in the last decade. Erwinia amylovora Burril. is the most devastating bacterial disease in the Rosaceae family, and there have been no reports of Cydomalus. In this study, fire blight susceptibility index of three Cydomalus genotypes, were collected from İzmir and Manisa provinces, and two important quince rootstocks were determined by artificial inoculations with the most virulent Erwinia amylovora strain of our collection, under greenhouse conditions for two consecutive years. In addition, susceptibility levels of two Cydomalus genotypes were observed under natural disease pressure habitats. In line with the results of artificial inoculations, two of Cydomalus genotypes were determined to be more tolerant to fire blight disease than quince rootstocks and these genotypes could be used in breeding studies. Moreover, Cydomalus genus was identified as the new host for Erwinia amylovora. [ABSTRACT FROM AUTHOR]

In this study, the effects of different rootstocks (including cultivars) on the quality and sensory properties of Shine Muscat grapes were investigated with own-rooted vines as control. Compared to the own-rooted vines, berry weight, TSS/TA and phenolic profiles were altered by the rootstocks to varying extents. The rootstocks widely altered the amounts of aroma components. Berries on 'Yuanyu' (YY), 'Bixiang Seedless' (BS), 'Couderc 3309' (3309C), 'Summer Black' (SB) and 'Queen Nina' (QN) significantly increased total aroma amount to the control berries, while 'Zaoxiaxiang' (ZX) imparted slight effects on the total aroma amount. Besides, the rootstock QN and 3309C markedly upregulated the VvLoXA, VvADH1 and VvADH2 expression levels, compared to the own-rooted grapevines, the berries observably upregulated seven genes from the MEP pathway in the grafted vines on SB and 3309C. In addition, the rootstock ZX, and 'Kober 5BB' (5BB) significantly increased the VvGT7 expression levels, the berries on YY significantly enhanced the expression of VvGT14. In summary, we found that the rootstock 3309C, QN and SB provided berries of better quality and richer aroma volatiles to SM berries, and the berries on QN (V. vinifera × V. labrusca varieties) had the largest total aroma amount and berry weight. [ABSTRACT FROM AUTHOR]

Vegetables constitute 12% of world agricultural produce. Solanaceous and cucurbitaceous crops constitute the major share of vegetable production, but their productivity is greatly impaired by plant-parasitic nematodes, among which root-knot nematodes pose the greatest threat. Due to climate change, water scarcity, shrinking of arable land, and ill effect of pesticides, a major shift in world agriculture is taking place toward sustainability, including organic and protected farming of high-value vegetable crops year-round. Grafting offers a sustainable alternative to conventional and transgenic breeding for nematode resistance. The technique can potentially reduce the phytonematode damage relying on several factors. These include R gene-mediated plant responses, efficient cross talk of defensive genes, alteration of plant metabolism and nutrient mobility, changes in plant vigor and physiological attributes, and modification of rhizosphere microbial community. Additionally, epigenetic factors also determine the success of graft union between the scion and rootstock. Grafting should also be included as a tool in integrated nematode management practices. Studies on identifying potential rootstocks and using grafted vegetable crops to manage nematode incidence are exhaustive but scattered. Here, we review the current status of vegetable grafting for nematode management using resistant rootstocks in both open-field condition and greenhouses. This is the first review, which compiles and summarizes the information on managing nematodes using grafted vegetables. We conclude the review with futuristic research perspectives of grafting that may aid in improving vegetable productivity in a sustainable manner. [ABSTRACT FROM AUTHOR]

Salt stress influences the physiological, biochemical, and molecular processes in plants affecting growth and development. This research aims to determine the salt stress tolerance of wild pear genotypes AH-1, AH-2, AH-3 (Pyrus elaeagrifolia Pall.), Ankara Pear clone 19 (AN-19) (P. communis L.) and clonal pear rootstocks OHxF 333 (P. communis L.) and quince (QA) (Cydonia oblonga Mill.) under in vitro conditions. Microshoots of each genotype were cultured in MS medium and subjected to NaCl combined with CaCl2 at four different concentrations for 4 weeks. The survival percentage of the OHxF 333, AN-19, QA, and AH-3 microshoots was found to be high (77.66–97.16%) at high salt concentrations. Number of shoots was significantly lower (1.0–2.52/explant) in salt treatments. While shoot length was generally similar to the control, shoot thickness, callus diameter, and fresh weight decreased with increasing salt concentration. Dehydrin gene (MdDHN) expression analysis revealed that QA, AH-3, OHxF 333, AH-2, and AN-19 genotypes responded to salinity stress earlier than others. The genotypes AH-3, OHxF 333, QA, and AN-19 exhibiting high survival percentage and earlier MdDHN expression were further evaluated for antioxidant activity (SOD, CAT, APX), total chlorophyll and proline contents and mineral elements that are involved in salt stress response of plants. Proline, H2O2 content and SOD activity were highest in AH-3, APX, and CAT activity were highest in QA at high salt concentration. Our findings revealed the salt stress response of Pyrus spp. and Cydonia oblonga genotypes used as rootstocks for pears. [ABSTRACT FROM AUTHOR]

One of the desired traits in rootstocks for stone fruits is tolerance to abiotic stresses, such as water deficit, which is one of the factors associated to peach tree short life syndrome that constitutes one of the main agronomic problems in Rio Grande do Sul's peach cultivation. This research aimed to discern the rootstock that best sustain water status and influences proline synthesis regulation in seven-year-old 'BRS-Kampai' peach trees grown non-irrigated sandy soil during the post-harvest period. Stem water potential in 'BRS-Kampai' peach trees was distinctly affected by the choice of rootstock, revealing heightened sensitivity to soil moisture depletion and atmospheric vapor pressure deficit escalation. When confronted with reduced gravimetric soil moisture (<7.0%), 'BRS-Kampai' peach trees grafted onto Clone 15 (Prunusmume) exhibited less negative stem water potential and higher leaf proline content, indicative of physiological adjustment to edaphoclimatic conditions. Conversely, 'BRS-Kampai' peach trees graffet onto 'Flordaguard' displayed increased vegetative growth. Notably, 'BRS-Kampai' own-rooted trees exhibited stem growth, leaf proline contents, and stem water potential similar to those of peach trees grafted onto 'Capdeboscq', thereby demonstrating robust adaptation to prevailing edaphoclimatic conditions. [ABSTRACT FROM AUTHOR]

In this study, the physiological and developmental response of ten promising almond genotypes to deficit irrigation was investigated. A factorial experiment was conducted in a completely randomized block design with three replications during 2019 and 2020 at the Temperate Fruit Research Center, Horticultural Research Institute. The first factor was ten almond genotypes, and the second factor was three levels of drought stress (–0.33 MPa as a control, 0.9 and 1.6 MPa as moderate and severe stress, respectively). The results showed that growth and physiological characteristics, such as plant height, trunk diameter at the top of the plant, length of new branch growth, and leaf yellowness, as well as chlorophyll index based on the SPAD criterion, relative leaf water content, chlorophyll fluorescence, and activity of leaf enzymes including SOD, POD, CAT, and APX, varied among the ten almond genotypes under different levels of drought stress. Higher proline, RWC, and Fv/Fm values indicated a higher ability to tolerate drought stress in almonds. The study conducted a heatmap clustering analysis to classify 10 almond genotypes based on their response to drought stress. The results showed that the genotypes were divided into three groups, with two genotypes in the first group being more sensitive to drought stress. Also, the A-7-100 genotype in the third group was found to be more tolerant and adapted to drought stress than the other genotypes. [ABSTRACT FROM AUTHOR]

Indole-3-acetic acid (IAA) is an important plant hormone required for various plant growth and developmental activities. YUCCA proteins are the enzymes for IAA synthesis that catalyze the rate-limiting step. However, the YUCCA gene family in Japanese apricot has not been thoroughly characterized. Here, we investigated the effect of rootstocks on scion growth of Japanease apricot and genes involved in auxin biosynthesis (YUCCA). Growth characteristics revealed that the height of 'Longyan' [Prunus mume Sieb. et Zucc] plants with P. mume rootstock were significantly shorter than 'Longyan' plants with P. persica rootstock. This study isolated 13 PmYUCCA genes from the Japanese apricot genome. Bioinformatics and expression studies were undertaken to investigate the functions and characteristics of YUCCA genes. The physicochemical properties, gene structure, conserved domains, conserved motif, and phylogenetic relationships of YUCCA genes were determined using bioinformatics analysis. Likewise, we analyzed the expression of PmYUCCA genes in Japanese apricot's leaf and stem-bark (scion). The expression levels of PmYUCCA3 and PmYUCCA5 genes were noticeably lower in the leaves of 'Longyan'/P. mume graft combination than that of the 'Longyan'/P. persica graft combinations, suggesting their distinct roles in regulating growth vigor. This research explores the genome-wide identification, characterization, and possible relationship between growth vigor and expression profile analysis of the YUCCA gene family in Japanese apricot. [ABSTRACT FROM AUTHOR]

Key message: Root constriction (RC) by wire mesh reduced yield and growth in young olive trees of high- and low-vigor cultivars. Yield efficiency, although different between cultivars, was unaffected by RC. There is strong interest in intensifying olive cultivation. This requires small plants with high and constant production. In this study, the effects of root constriction (used as a dwarfing technique) on growth and yield efficiency of young olive trees were evaluated. Two cultivars with different vigor 'Arbequina' (low vigor) and 'Frantoio' (high vigor) planted in a super-high-density (SHD) olive grove were compared. At transplanting (2006), the tree roots were placed in a galvanized wire mesh container and buried with it. Tree growth, biomass of pruning material and productivity were then compared with a control treatment without wire mesh. By the end of the trial (2016), 'Frantoio' had much larger trunk cross-sectional area (TCSA) than 'Arbequina', and for both cultivars, the plants with the wire mesh had lower TCSA than the control: 47% and 36% less in 'Arbequina' and 'Frantoio', respectively. Pruning biomass was almost none in 'Arbequina' and much higher in 'Frantoio' and for both cultivars, higher in the control. Cumulative yield was similar between cultivars, but about half in the wire mesh treatments. Yield efficiency was higher in Arbequina, but similar between treatments, within cultivars. Total tree growth (i.e., TCSA increment over the experiment) across all treatment combinations (2 cultivars × 2 treatments) was inversely related to yield efficiency. The results show that root constriction allows reducing tree growth without changing yield efficiency. This could potentially allow maintaining a fruiting canopy for longer in SHD systems, thus improving the suitability of traditional vigorous cultivars to this new system. [ABSTRACT FROM AUTHOR]

Fusarium oxysporum f. sp. lycopersici (FOL) is one of the most destructive diseases of tomatoes in Iran, causing severe yield losses and quality reduction. However, not many studies have been conducted to explore the use of resistant rootstocks for managing this disease and minimizing production losses in the region. In this study the level of resistance of multiple tomato cultivars and lines were evaluated against FOL. The most FOL-resistant cultivars were then selected as possible rootstocks and two resistant scions were grafted onto them. FOL was inoculated and the resistance of grafted plants was assessed using several indices, including disease incidence (DI), disease severity (DS), and area under the disease progress curve (AUDPC). In addition, stem length and diameter of the grafted samples were measured. Out of 29 lines and cultivars, only nine, including, Koper, 1616, TOM5, IR.SR3, 1626, 1631, IR.SA1 and the resistant Maxifort and Beaufort check cultivars, found to be the most resistant against FOL and were subsequently used for rootstocks. Koper and 1616 rootstocks exhibited the lowest percentages of AUDPC, DS and DI compared to the grafted plants as well as the susceptible and two resistant checks. They also exhibited relatively greater stem length and diameter. The results in this study suggest the potential of resistant rootstocks in preventing disease progression, which also provide possibilities for control of wilt disease and low-input sustainable horticulture in the region. [ABSTRACT FROM AUTHOR]

Salinity stress is a key factor affecting grape production in coastal areas. Two grape rootstock cultivars, 'Beta' (sensitive to salt stress) and '3309 C' (resistant to salt stress), were used to investigate the physiological role of 5-aminolevlinic acid (5-ALA) in salinity tolerance. Functional capacities in the rhizosphere, leaf phenotype, photosynthetic parameters, antioxidant enzymes activities and certain physiological indexes were determined after treatment with seawater or seawater followed by 100 mg/L 5-ALA application. The results showed that the functional capacities of the rhizosphere were distinct between the two management regimes. Microbial biomass and soil enzyme activities were reduced by salinity but promoted by 5-ALA. Salinity also suppressed the overall plant growth, leaf chlorophyll content, photosynthetic rate, maximal photochemical efficiency (Fv/Fm), photochemical quenching (qP), electron transport rate (ETR), root activity, ATP content, ATPase activity, and activities of the antioxidant enzymes ascorbate peroxidase (APX), peroxidase (POD), catalase (CAT), and superoxide dismutase (SOD) in both cultivars. Although plant growth, chlorophyll content, and activities of antioxidant enzymes in Beta were decreased to a greater extent than those in 3309 C under salinity stress, exogenous application of 5-ALA significantly improved plant growth along with enhancement of all the above photosynthetic parameters and activities of the four antioxidant enzymes in both cultivars. Seawater treatment alone significantly increased non-photochemical quenching (NPQ), relative electrical conductivity (REC), and malondialdehyde (MDA) contents in leaves, especially for Beta. However, 5-ALA treatment decreased the levels of NPQ, REC, and MDA, but increased ATP content and ATPase activity in roots and leaves of both cultivars. Thus, application of 5-ALA would be beneficial to improve the salt tolerance of grape rootstocks grown in coastal areas. [ABSTRACT FROM AUTHOR]

The negative effects of waterlogging can be effectively improved through the use of waterlogging-resistant rootstocks. However, the underlying physiological and molecular mechanisms of Chinese bayberry (Morella rubra) rootstock tolerance to waterlogging have not yet been investigated. This study aims to unravel the molecular regulation mechanisms underlying waterlogging-tolerant rootstocks. Two rootstocks, Morella cerifera (tolerant) and Morella rubra (sensitive), were selected for root zone hypoxia treatments, assessments of hormone levels and antioxidant enzyme activity, and transcriptomic analysis. While the contents of abscisic acid (ABA) and brassinosteroid (BR) in the roots of M. rubra decreased significantly after root zone hypoxia treatment, there were no significant changes in M. cerifera. Both the superoxide dismutase (SOD) activity and malondialdehyde (MDA) content increased in M. cerifera but were decreased in M. rubra. Transcriptome sequencing identified 1,925 (928 up- and 997 downregulated) and 733 (278 up- and 455 downregulated) differentially expressed genes (DEGs) in the two rootstocks. The gene set enrichment analysis showed that 84 gene sets were enriched after root zone hypoxia treatment, including 57 (35 up- and 22 downregulated) and 14 (five up- and nine downregulated) gene sets derived from M. cerifera and M. rubra, respectively, while the remaining 13 gene sets were shared. KEGG pathway analysis showed specific enrichment in six pathways in M. cerifera, including the mitogen-activated protein kinase (MAPK), tyrosine metabolism, glycolysis/gluconeogenesis, ribosome, cyanoamino acid metabolism, and plant-pathogen interaction pathways. Overall, these results provide preliminary insights into the molecular mechanisms of Chinese bayberry tolerance to waterlogging. [ABSTRACT FROM AUTHOR]

The hard-end of pear fruit might be a disorder of the environmental abiotic stress, which is mainly caused by the reduced water intake of the fruit resulting from climate drought. To explore the factors that cause fruit hard-end, two rootstocks of Pyrus betulaefolia and P. bretschneideri with different root absorptive capacity of water and nutrients were used as base stock of 'Whangkeumbae' (P. pyrifolia) pear fruit. The results showed that the incidence of hard-end fruit in 'Whangkeumbae' pear trees using rootstock with lower rate of water absorptive increased, indicating that this physiological disorder was related with water deficiency. PpNAC187 was selected from RNA-Seq carried out on the calyx end of with and without the hard-end symptom of different rootstocks. The transgenic tobacco overexpressing PpNAC187 showed higher tolerance with drought and salt stress, which might suggest that PpNAC187 acts an important role during the hard-end occurring caused by drought or salt stress. [ABSTRACT FROM AUTHOR]

Aims: The effect of flooding on carbohydrate and nitrogen metabolism in leaves of peach (Prunus persica cv. UFSun) trees grafted onto six different Prunus spp. rootstock cultivars with either peach or plum parentage (peach: 'Flordaguard', 'Guardian', 'Nemaguard', 'P-22'; plum: 'R5064–5', and 'MP-29') were evaluated. Methods: Young peach trees were divided into two treatments: 1) non-flooded (control) and 2) flooded trees. Trees in the flooded treatment were subjected to 8 days of flooding (the root zone was submerged in containers filled with tap water) before leaves were harvested for biochemical analyses. Carbohydrate contents, enzymatic activity related to sucrose metabolism, glycolysis, nitrogen assimilation, and nitrogen metabolism of the scions were sampled from 40 leaves from each replication of each treatment. Results: Enzymatic activities of acid invertase were lower, and neutral invertase, sucrose synthase, and sucrose phosphosynthase were higher in scions of flooded trees compared to those of non-flooded trees. Trees in the flooded treatment had lower activity of enzymes involved in glycolysis. Carbohydrate contents (glucose, sucrose, and fructose) were higher in flooded than control plants for scions on all rootstocks except 'Flordaguard', in which the scion glucose level was not different between treatments. Scions in the flooded treatment had lower activity of enzymes involved in nitrogen assimilation and metabolism, and consequently lower NO3− and NO2− content than scions of trees in the non-flooded treatment. Conclusions: Flooding of P. persica cv. UFSun on six different Prunus spp. rootstocks caused enzymes in leaves of the scion involved in sucrose metabolism to be more active compared to those in the non-flooded control treatment. However, most enzymes involved in glycolysis were less active in flooded than non-flooded trees, except in scions on plum rootstocks, whose hexokinase (HK) and fructokinase (FK) enzymes were more active in the flooded than the non-flooded treatment. This suggests that scions on plum rootstocks could be more efficient at generating hexose sugars during glycolysis. The higher contents of sugars present in scions on flooded compared to non-flooded rootstocks could be indicative of translocation being hindered by flooding. Compared to non-flooded trees, flooding generally resulted in lower enzymatic activity related to nitrogen assimilation and metabolism (scions on plum rootstocks were largely unaffected), which consequently led to lower levels of nitrate and nitrite, while ammonium levels were higher in flooded scions. The lower HK and FK activities in scions on peach rootstocks compared to plum rootstocks may have made photosynthesis hexose limited, which would disrupt the electron transport chain and lead to less energy being available for nitrogen assimilation and metabolism as these processes are connected. [ABSTRACT FROM AUTHOR]

Citrus holds the key position in horticulture sector of Pakistan in terms of area and production. Kinnow is considered as the trademark of Pakistan's citriculture industry. Cultivation experiment was conducted to evaluate the endogenous plant hormones, leaf gas exchange, photosynthetic pigments, vegetative performance, and yield of Kinnow mandarin grafted on nine rootstocks (Rough lemon, cox mandarin, Fraser hybrid, Troyer citrange, Cleopatra mandarin, Poncirus trifoliata, Benton, C-35, and Carrizo citrange). Maximum indole acetic acid (IAA), gibberellic acid (GA3), and zeatin (ZT) levels were recorded in scion and rootstock of Poncirus trifoliata followed by Fraser hybrid. Troyer citrange rootstock depicted maximum amount of abscisic acid in scion and rootstock. Maximum leaf gas exchange in Kinnow mandarin was recorded on Fraser hybrid rootstock. Kinnow grafted on Troyer citrange rootstock had minimum stomatal conductance and photosynthetic activity because of high ABA level. Photosynthetic pigments of Kinnow mandarin were maximum on Poncirus trifoliata and minimum on Troyer citrange. A positive correlation was observed among the levels of IAA, GA, ZT, and vegetative growth of Kinnow mandarin. It is concluded that endogenous hormones modulated the growth of Kinnow mandarin. Poncirus trifoliata and Fraser hybrid rootstocks could be an alternate rootstocks of traditional Rough lemon for Kinnow mandarin. [ABSTRACT FROM AUTHOR]

Citrus cultivation has socioeconomic relevance, and gummosis Phytophthora diseases considerably reduce its yield. This infection has motivated the development of diagnostic procedures in the Citrus-Phytophthora pathosystem to assist breeding programs in selecting resistant rootstocks. The objective of this study was to standardize a method for detecting nuclei Phytophthora sp. for study the colonization process and the life cycle of the pathogen in infected stems of Rangpur lime rootstocks using flow cytometry. The stems were inoculated with a Phytophthora sp. isolated from a citrus population of Bom Jesus da Lapa, Bahia, Brazil. Firstly, the DNA ploidy level and nuclear genome size were determined from the mycelium cells of Phytophthora sp. and leaf cells of Rangpur lime, using the saline extraction buffer, procedure of preparation of suspensions in two stages (isolation and staining), with centrifugation of the nuclei suspensions and discard of the supernatant. The mean number of 1C (gametangia) and 2C (other tissues) Phytophthora sp. nuclei in Rangpur lime was estimated based on the reference values relative to the position of G0/G1 peaks of the 2C nuclei of Phytophthora sp. and of the Rangpur lime rootstock and based on the standardization of the amount of infected tissue, and the volume of nuclear suspension analyzed. In infected Rangpur lime, there is a higher mean number of 2C nuclei of Phytophthora sp., which correspond to hyphae in the vegetative growth stage, dispersion spores, and infection structures of the pathogen's life cycle. On the other hand, 1C nuclei, in smaller quantities, correspond to gametangia. Therefore, the established flow cytometry procedure was reproducible and relatively fast for study the colonization process and the life cycle of the Phytophthora sp. on diseased plants of Rangpur lime. [ABSTRACT FROM AUTHOR]

Key message: Plant biostimulants did not improve citrus health and productivity in an HLB-endemic environment after two years, but fulvic acids increased concentrations of some nutrients and influenced the rhizosphere microbial community. Fibrous root loss is one of the main factors associated with citrus tree decline due to Huanglongbing (HLB) disease in Florida, and there is increased interest to use soil amendments such as plant biostimulants to improve root health and crop production. The effect of individual and combined applications of seaweed extracts, humic substances, and microbial inoculants on root and tree health, tree nutritional status, and productivity was investigated in an HLB-endemic environment. Experiments were conducted in two differently managed commercial citrus orchards. The effect of the treatments on the composition and structure of the citrus rhizosphere bacterial and fungal community was examined and linked to variations in root macro- and micronutrient concentrations. Overall, treatments had no effect on disease index ratings, total and specific root lengths, root physiological responses, and fruit quality and yield after two years of application. Only the individual applications of fulvic acids resulted in statistically significant increases in root and leaf macro- and micronutrient concentrations compared to the control treatment, an effect that differed between trials. These increases in root macro- and micronutrient concentrations were linked to variations in the relative abundance of specific bacterial and fungal taxa in the citrus rhizosphere. Our results suggest that longer-term and higher application rates of fulvic acids may be necessary to translate rhizosphere effects into measurable effects on tree health and productivity in HLB-endemic conditions. We show that factors such as different management practices and soil and environmental conditions may determine efficacy of biostimulants on root and tree health. [ABSTRACT FROM AUTHOR]

Grafting is an important practice in mango (Mangifera indica L.) orchard management for propagating elite germplasm but there is limited information on the effect of rootstock-scion interactions on the mineral nutrition of mango. Here, we analyzed the variations in leaf nutrients of commercial ('B74' and 'Kensington Pride' [KP]) and newly developed cultivars from the National Mango Breeding Program (NMBP) ('NMBP1243', 'NMBP1201', and 'NMBP4069') grafted onto six different rootstocks ('B', 'KP', 'Mallapunyah', 'SabahBRF', 'Vellaikulamban', and 'Watertank') to determine the influence of the rootstock on the scion leaf nutrient content. Deviation from the optimum percentage (DOP and ΣDOP indexes) was calculated to compare nutrition status/balance among the different rootstocks. Leaf nutrient concentrations and their DOP index were affected by the rootstocks and scions. None of the rootstocks or scions had consistently higher or lower nutrient levels, and interaction effects between rootstock and scion factors were insignificant. The DOP index indicated an imbalance of nutrients in the leaves, but scions grafted onto rootstocks 'Vellaikulamban' and 'SabahBRF' were more nutritionally balanced, indicating that they are preferred rootstocks for propagation. Principal component analysis showed a clear separation among rootstocks according to their differences in nutrient concentrations, such that 'Vellaikulamban' and 'SabahBRF' (Group 1) were different from 'Watertank' and 'B' (Group 2) as well as from 'KP' and 'Mallapunyah' (Group 3). Scions were clustered based on their similarities with 'B74' and 'NMBP1201' in Cluster 1, 'NMBP 4069' in Cluster 2, 'NMBP 1243' in Cluster 3, and 'KP' in Cluster 4. This study provides valuable information to understand the potential impact of the rootstock on the nutritional status of scions as well as for the selection of rootstock-scion combinations for variety improvement. [ABSTRACT FROM AUTHOR]

To alleviate the effects of increasingly severe environmental conditions and meet the increasing demand for organic agricultural products, this paper studied tomato grafting under low nitrogen conditions in an effort to enhance yield and improve fruit quality by enhancing nitrogen metabolism. In this study, we screened for two tomato genotypes, a high nitrogen use efficiency genotype ('TMS-150') and a low nitrogen use efficiency genotype ('0301111'), using rootstocks from 25 tomato genotypes and studied the effects of tomato grafting on plant yield, fruit quality, nitrogen content, activities of key nitrogen metabolism enzymes, and nitrogen use efficiency (NUE) under different nitrogen fertilizer conditions. The results showed that the yield of the tomato plants, the activities of key enzymes during nitrogen metabolism, the contents of different forms of nitrogen, and the efficiency of nitrogen use were lower at low nitrogen fertilization levels and higher at higher nitrogen fertilization levels, while the measured indicators were the highest under the N40 nitrogen fertilizer treatment. Grafting tomatoes with high-NUE tomato seedlings as the rootstock resulted in significant increases in the nitrogen content and the activity of key enzymes, enhanced the NUE of tomato plants, increased tomato yield, and improved fruit quality compared to those of the seedlings grafted with low-NUE rootstock. Our results indicate that tomato plants grafted with high-NUE rootstock presented enhanced absorption and utilization of nitrogen and increased plant yield by promoting nitrogen metabolism at different nitrogen levels. [ABSTRACT FROM AUTHOR]

Interspecific hybrid Cucurbita rootstocks (Cucurbita maxima × Cucurbita moschata) are the most widely used rootstocks for Cucurbitaceous vegetables in the world. In recent years, scientists have focused on understanding and exploiting root architectures as new opportunities for crop improvement. Selection of parents and hybrids based on combining ability test is an effective approach in interspecific hybrid variety breeding. However, limited information is available on the combining ability tests for the rooting and graft-related traits in these rootstocks. Ondokuz Mayis University and Black Sea Agricultural Research Institute are conducting a program to breed Cucurbita rootstocks in Turkey for fifteen years. In this study, seven C. maxima (BC5F1 generation) lines as female parents and three C. moschata (S6 generation) lines as male parents were used to obtain 21 crosses. The watermelon grafted onto the interspecific hybrids and their parent rootstocks were analyzed in terms of general combining ability (GCA), specific combining ability (SCA), heritability, and heterosis for roots and graft-related traits including root volume (cm3), root length (m), root dry weight (g), hairy root rate (%), average root diameter (mm), shoot dry weight (g), graft success rate (%), and hypocotyl thickness ratio (%) by using line × tester mating design. The quotient of GCA/SCA effects for all root and hypocotyl traits were higher than 1, suggesting the preponderance of additive over non-additive gene action in the expression of these traits, whereas graft success was controlled by additive and non-additive gene effects. It was determined that average root diameter had high heritability (63.85%) and the other traits had intermediate heritability ranging from 40.59 to 58.98%. Combining ability analyses indicated that FTS5, GH12, and GRD17 lines were promising parents with greater general combining ability. Three crosses, GRD17 × FTS5, B12 × FTS5, and BH5 × CHI2 showed superior mid-parent heterosis and significant SCA for most studied characteristics. Present findings will provide significant contributions in understanding of root related characteristics and then achieving desirable improved rootstocks in C. maxima × C. moschata. [ABSTRACT FROM AUTHOR]

Grafted fruit trees are made up of two parts, the scion and the rootstock. The rootstocks affect the growth and physiological and biochemical treats of scion. The use of grafting technique in vitro produces healthy plants and allows careful study of rootstock and scion interactions. The objective of this research was to achieve a successful protocol for micrografting of the late-flowering Sahand cultivar on two wild almond rootstocks (Badam Kohi and Arjan) and also to determine the best rootstock for mentioned cultivar. In this regard, a factorial experiment was conducted to investigate the effect of rootstock type, culture medium (MD1 = MS, MD2 = MS +0.49 µM IBA + 2.2 µM BA, MD3 = MS + 2.46 µM IBA + 0.44 µM BA) and supporting system (paper bridge and perlite) on micrografting success of 'Sahand' scion. The results showed that in micrograft combination of 'Sahand'/Badam kohi, the highest grafting success (100%) and scion length (27.8 mm) were achieved on the MD2 medium with perlite. The Arjan rootstock increased electrolyte leakage and decreased total chlorophyll of the scion in compare to Badam Kohi rootstock. In the grafted combinations, the highest amount of superoxide dismutase, peroxidase and catalase activities were recorded in 'Sahand' on the Badam Kohi rootstock which were significantly higher than in the same scion on Arjan rootstock. It can be concluded that Badam Kohi is more suitable than Arjan as a rootstock for Sahand cultivar. Key message: In vitro wedge micrografting was successfully established for Sahand cultivar on wild almond rootstocks using IBA and BA combinations in culture media. Badam Kohi rootstock supported 'Sahand' scion by induced more antioxidant enzymes than Arjan rootstock. [ABSTRACT FROM AUTHOR]

Background: Grapevine is associated with various microorganisms, forming an holobiont. The age of the grapevine and the effect of several declines on the root mycobiota was already studied.Grapevine is an heterografted plant with two different genotypes coexisting, the one from the rootstock and the one from scion. We studied both the effect of rootstock genotype and the grafting of a grape variety on the grapevine root mycobiota.The experiment was carried out in a conservatory vineyard in Burgundy (France) made of two collections: one with rootstocks grown as ungrafted and one with several grape varieties grafted onto the 5C or SO4 rootstocks. Physico-chemical properties were characterized. Soil and roots were sampled to analyse fungal communities with a metabarcoding approach using ITS and LSU as targets and specific of fungi and arbuscular mycorrhizal fungi, respectively.Whatever the rootstock, a core mycobiota was associated with roots. In addition, part of root mycobiota is influenced either by the rootstock or by the scion or by the soil. The genetic background could not be fully explored, but it could have a role in the differential recruitment of microorganisms.Further studies should focus on both rootstock and scion part, independently and crosswise, in order to better understand the mechanisms involved in specific root microbial interactions within the grapevine holobiont, and to provide a better response to the health and environmental problems affecting grapevines.Aims: Grapevine is associated with various microorganisms, forming an holobiont. The age of the grapevine and the effect of several declines on the root mycobiota was already studied.Grapevine is an heterografted plant with two different genotypes coexisting, the one from the rootstock and the one from scion. We studied both the effect of rootstock genotype and the grafting of a grape variety on the grapevine root mycobiota.The experiment was carried out in a conservatory vineyard in Burgundy (France) made of two collections: one with rootstocks grown as ungrafted and one with several grape varieties grafted onto the 5C or SO4 rootstocks. Physico-chemical properties were characterized. Soil and roots were sampled to analyse fungal communities with a metabarcoding approach using ITS and LSU as targets and specific of fungi and arbuscular mycorrhizal fungi, respectively.Whatever the rootstock, a core mycobiota was associated with roots. In addition, part of root mycobiota is influenced either by the rootstock or by the scion or by the soil. The genetic background could not be fully explored, but it could have a role in the differential recruitment of microorganisms.Further studies should focus on both rootstock and scion part, independently and crosswise, in order to better understand the mechanisms involved in specific root microbial interactions within the grapevine holobiont, and to provide a better response to the health and environmental problems affecting grapevines.Methods: Grapevine is associated with various microorganisms, forming an holobiont. The age of the grapevine and the effect of several declines on the root mycobiota was already studied.Grapevine is an heterografted plant with two different genotypes coexisting, the one from the rootstock and the one from scion. We studied both the effect of rootstock genotype and the grafting of a grape variety on the grapevine root mycobiota.The experiment was carried out in a conservatory vineyard in Burgundy (France) made of two collections: one with rootstocks grown as ungrafted and one with several grape varieties grafted onto the 5C or SO4 rootstocks. Physico-chemical properties were characterized. Soil and roots were sampled to analyse fungal communities with a metabarcoding approach using ITS and LSU as targets and specific of fungi and arbuscular mycorrhizal fungi, respectively.Whatever the rootstock, a core mycobiota was associated with roots. In addition, part of root mycobiota is influenced either by the rootstock or by the scion or by the soil. The genetic background could not be fully explored, but it could have a role in the differential recruitment of microorganisms.Further studies should focus on both rootstock and scion part, independently and crosswise, in order to better understand the mechanisms involved in specific root microbial interactions within the grapevine holobiont, and to provide a better response to the health and environmental problems affecting grapevines.Results: Grapevine is associated with various microorganisms, forming an holobiont. The age of the grapevine and the effect of several declines on the root mycobiota was already studied.Grapevine is an heterografted plant with two different genotypes coexisting, the one from the rootstock and the one from scion. We studied both the effect of rootstock genotype and the grafting of a grape variety on the grapevine root mycobiota.The experiment was carried out in a conservatory vineyard in Burgundy (France) made of two collections: one with rootstocks grown as ungrafted and one with several grape varieties grafted onto the 5C or SO4 rootstocks. Physico-chemical properties were characterized. Soil and roots were sampled to analyse fungal communities with a metabarcoding approach using ITS and LSU as targets and specific of fungi and arbuscular mycorrhizal fungi, respectively.Whatever the rootstock, a core mycobiota was associated with roots. In addition, part of root mycobiota is influenced either by the rootstock or by the scion or by the soil. The genetic background could not be fully explored, but it could have a role in the differential recruitment of microorganisms.Further studies should focus on both rootstock and scion part, independently and crosswise, in order to better understand the mechanisms involved in specific root microbial interactions within the grapevine holobiont, and to provide a better response to the health and environmental problems affecting grapevines.Conclusion: Grapevine is associated with various microorganisms, forming an holobiont. The age of the grapevine and the effect of several declines on the root mycobiota was already studied.Grapevine is an heterografted plant with two different genotypes coexisting, the one from the rootstock and the one from scion. We studied both the effect of rootstock genotype and the grafting of a grape variety on the grapevine root mycobiota.The experiment was carried out in a conservatory vineyard in Burgundy (France) made of two collections: one with rootstocks grown as ungrafted and one with several grape varieties grafted onto the 5C or SO4 rootstocks. Physico-chemical properties were characterized. Soil and roots were sampled to analyse fungal communities with a metabarcoding approach using ITS and LSU as targets and specific of fungi and arbuscular mycorrhizal fungi, respectively.Whatever the rootstock, a core mycobiota was associated with roots. In addition, part of root mycobiota is influenced either by the rootstock or by the scion or by the soil. The genetic background could not be fully explored, but it could have a role in the differential recruitment of microorganisms.Further studies should focus on both rootstock and scion part, independently and crosswise, in order to better understand the mechanisms involved in specific root microbial interactions within the grapevine holobiont, and to provide a better response to the health and environmental problems affecting grapevines. [ABSTRACT FROM AUTHOR]

The characteristics of rootstock have impacts scion's nutritional status, resistance to environmental stresses and adaptation to a specific region. Thus the performance of a cultivar is largely dependent on the rootstock-scion interactions. In this study, seasonal variations in mineral nutrients of 'Nova' and 'Robinson' mandarin cultivars budded on different citrus rootstocks were investigated under Dörtyol-Hatay (Turkey) ecological conditions. Nitrogen (N), phosphorus (P) and potassium (K) contents of the leaves exhibited slightly similar trends with each other. In general, these nutrients decreased from January to March-April and increased in the subsequent growing season until mid- and late summer, then decreased again until December. Similar trends were also observed in calcium (Ca) and magnesium (Mg) concentrations of leaves. Leaf Ca and Mg concentrations decreased from January to March, then increased during fruit development until July-August and decreased again during autumn and winter. Also, micro elements such as iron (Fe), zinc (Zn), manganese (Mn) and copper (Cu) increased from January to May–June and then gradually decreases began during the growing season until December. Throughout the entire growing season, mean macro nutrients such as N, K and Ca concentrations ranged from 1.89% ('Nova'/Carrizo citrange) to 2.02% ('Robinson'/Carrizo citrange), from 1.10% ('Robinson'/Carrizo citrange) to 1.39% ('Nova'/Carrizo citrange) and from 2.62% ('Nova' /sour orange) to 3.48% ('Robinson'/Troyer citrange), respectively. Phosphorus and Mg concentrations showed slightly similar trends and varied between 0.14–0.16% and between 0.31–0.39%, respectively. The ranges of mean micro nutrients such as Fe, Zn, Mn and Cu concentrations were between 65.3 and 75.4 mg kg−1, 33.7 and 39.6 mg kg−1, 64.1 and 70.6 mg kg−1, and 10.5 and 11.4 mg kg−1, respectively. It can be concluded that rootstock-scion relations can cause considerable differences in seasonal nutrition of mandarin cultivars. [ABSTRACT FROM AUTHOR]

Bacterial wilt (BW), caused by Ralstonia solanacearum species complex (RSSC), is a major disease affecting tomato and other solanaceous crops produced in Louisiana and worldwide. The most effective and economic management strategy for BW is the use of crop genetic resistance. However, regional genetic variation among RSSC strains has made stable and durable resistance elusive. A collection of tomato, eggplant and pepper (TEP) accessions that responds to globally diverse strains in the RSSC was screened for resistance to six RSSC strains, belonging to phylotypes I and II, from Louisiana, United States (US). Wilt severity was quantified from six days up to 25 days post-inoculation (DPI). Wilting increased most rapidly to 10 DPI and was generally more severe with Phylotype II strains. However, wilt response profiles depended on the accession-strain combination. Differences in aggressiveness, as measured by the area under the disease progress stairs, were observed among the phylotype I and II strains on TEP. Wilting responses were the most severe with the tomato accessions. Hawaii 7996, TML46, CLN1463 and R3034 were highly resistant to all phylotype I strains, but Hawaii 7996 displayed the best resistance to phylotype II strains. Remarkably, eggplant accession Ceylan SM 164 was resistant to all six strains. Eggplant accessions SM6, Surya, and AG91–25, as well as pepper accessions CA8 and MC4, were moderately to highly resistant to all six strains. Although resistance spectrum and levels of these tomato, eggplant and pepper accessions need to be confirmed by further experiments, our results already indicate that these accessions are potential BW-resistant rootstock candidates for grafting to susceptible market-driven tomato, eggplant and pepper produced in this US state. [ABSTRACT FROM AUTHOR]

Root rot is an emerging disease of grafted watermelon in China that causes severe yield losses. The causal agents associated with this disease were characterized in this study. A total of 70 fungal isolates were recovered from infected roots, and the most prevalent isolates were identified as Fusarium oxysporum (31% of isolates recovered). F. oxysporum isolates induced typical root rot disease symptoms in pathogenicity tests, whereas the other isolates were nonpathogenic. On the basis of combined DNA sequence analyses, specific pathogenicity tests and root rot symptoms, the F. oxysporum was identified as F. oxysporum f. sp. radicis-lagenariae. We evaluated 37 bottle gourd rootstocks for resistance to F. oxysporum f. sp. radicis-lagenariae. The mean disease rating scores (DRSs) ranged from 1.1 to 4.0 at 20 days after inoculation. The rootstock 16S-71 was most resistant to infection. These findings provide useful information for the development of bottle gourd rootstocks with resistance to fusarium root rot and to manage this disease. [ABSTRACT FROM AUTHOR]

Walnut trees are among the most important hardwood species in the northern hemisphere, ecologically and economically. They are mainly cultivated for timber and nut production but are also attractive ornamental trees in parks. Establishing walnut orchards is difficult because seedlings have a coarse root architecture and few of them survive to transplanting. Planting success is mainly determined by the root system morphology and the nutrient status of the seedlings, so that rhizosphere conditions are critical for plant performance. Walnut trees can associate with soil-borne arbuscular mycorrhizal fungi, which are obligate biotrophs. In this association, plant-produced carbon compounds are traded against fungus-acquired soil mineral nutrients. The beneficial effect of arbuscular mycorrhizal symbiosis on hardwood seedling quality and field performance has long been known, but an integrated view is lacking about the effects of arbuscular mycorrhizas on walnut cropping. Therefore, we surveyed the literature published over the last 40 years to provide up-to-date knowledge on the relationships between arbuscular mycorrhizas and walnut trees. Our review outlines the major following points: (1) the arbuscular-mycorrhiza-mediated nutrient uptake capacity of walnut trees is associated with first- to third-order roots, and fibrous tip-ended roots are dependent on arbuscular mycorrhizal fungi, whereas pioneer roots are not; (2) early inoculation with arbuscular mycorrhizal fungi improves the survival and seedling performance attributes of transplanted walnut trees: biotization enhances walnut transplant success by increasing the number of lateral roots and plant P uptake, but these benefits are fungus- and host-dependent; (3) in the context of walnut agroforestry, deeply rooted walnut trees play a role as reservoirs of arbuscular mycorrhizal fungal propagules for the surrounding vegetation, but tree shade and soluble phosphate availability decrease walnut mycorrhizal dependency; and (4) the arbuscular mycorrhizal mycelium mediates the transport of juglone and thus plays a role in walnut tree allelopathy. [ABSTRACT FROM AUTHOR]

Extensive plum production in Serbia has led to a reduction in yield, quality and economic profitability, a transition to intensive production is necessary. The aim of the present study was to investigate the effects of different generative (Prunus cerasifera, Prunus cerasifera + Prunus spinosa) and vegetative (WaVit, WeiWa) rootstocks in a dense planting system (4 m × 2 m). The experiment was conducted on early high-quality domestic cultivar 'Čačanska Lepotica' characterised by high adaptive ability in different agro-climatic conditions. The orchard was established in 2012 at the Experimental Field for Fruit Growing of the Faculty of Agriculture Novi Sad at Rimski Šančevi, and the experiment was conducted from 2013 to 2017. Based on the research findings, Prunus cerasifera rootstock induced higher tree trunk cross-section area, while also enhancing the total soluble solids content in the fruit. Trees grafted on Prunus spinosa interstock with Prunus cerasifera as the rootstock exhibited the smallest vigour, cumulative yield and titratable acidity. On the other hand, vegetative rootstocks increased the fruit yield, weight and size. [ABSTRACT FROM AUTHOR]

Pharmaceutical, food and cosmetic industries have shown great interest in grape seed extract due to its premium antioxidant activity with protective effects on human health. However, global climate change has already negatively affected the biochemistry and functionality of such nutraceutical crops. The present study was conducted to reveal the effects of sustained deficit irrigation on certain features of seed extracts obtained from the grape cultivar 'Prima' grafted on six genetically different rootstocks during two consecutive years. In both years, seed weight of 'Prima' grapes grafted on 5 BB significantly decreased in response to water treatments, although the other rootstocks did not impair the seed weight, except for 44–53 M in 217. Significant decreases in antioxidant activity of the scion cultivar occurred in response to DI when grafted on 5 BB in both years and in 44–53 M in 2017. However, the use of 99 R, 110 R and 140 Ru did not markedly impair the seed antioxidant activity in response to DI condition in both years. In both years, seed anthocyanins of FI vines were always higher than those of DI vines. In 2017, there were significant decreases in anthocyanins due to DI in vines grafted on 5 BB, 44–53 M, 99 R and 110 R. These rootstocks also led significant decreases in anthocyanins of the second year, while the use of 140 Ru and 1613 C rootstocks did not lead significant changes in anthocyanins in both two years. In 2017, total phenolics increased in response to DI, except for the vines grafted on 44–53 M. Rootstock-dependent changes in total phenolics in response to irrigation treatments were insignificant for the vines grafted on 5 BB and 44–53 M in both two experimental years. Averaged data showed that antioxidant activity showed significantly positive correlation with anthocyanins and total phenols. The findings are anticipated to guide future projects on enhancement of the quality and quantity of precious seconder metabolites with sustainable precision viticulture techniques to match the globally increasing demands on bioactive compounds. [ABSTRACT FROM AUTHOR]

Vegetable grafting is developing worldwide to cope with biotic and abiotic stresses. This technique faces strong regional disparities and its potential to improve crop performances is currently underexploited in sub-Saharan Africa. This review explores the potential of grafting to increase and secure vegetable production in challenging production conditions in sub-Saharan Africa and to identify the obstacles to its adoption. The major conclusions that can be drawn from the review are (1) the capacity of vegetable grafting to overcome several agronomic challenges commonly encountered in sub-Saharan Africa particularly for soilborne diseases; (2) grafting does not systematically lead to higher yields since the performance of grafted plants is closely linked with the combination of scion–rootstock chosen; (3) resistant rootstocks to the local soilborne pathogens could be identified through short-term laboratory and field experiments whereas the improvement of the tolerance to abiotic stresses would require deeper knowledge on underlying mechanisms; (4) the significant increase in the cost of using grafted plants are warranted in systems where there are no other technical alternatives to manage biotic and abiotic stresses, where profitability per plant is high, or where the use of grafted plants makes it possible to reach a profitable niche market such as off-season or organic products; and (5) vegetable grafting should therefore be promoted by providing evidence for its profitability in different production systems (open field and greenhouse cultivation) combined with supply-side interventions to build or strengthen the capacity of nursery operators to provide a continuous supply of good-quality grafted plants. [ABSTRACT FROM AUTHOR]

Anthocyanin biosynthesis is reported to be controlled by one of the transcription factors, called MdMYB1 in apple fruit skin. MdMYB1-1, one allele of MdMYB1 gene, is the only allele associated with the red skin color and other alleles produce yellow or green skin apples. In this study, five single-nucleotide polymorphism (SNP) markers were developed to distinguish which is red-skinned or non-red apples based on the sequences of MdMYB1 alleles. The SNP markers were assessed by high-resolution melting (HRM) analysis according to the melting curves patterns. The "M.9" and "M.26" are the widely used dwarfing rootstocks in South Korea. The discrimination of rootstocks using morphological traits is almost impossible as apple trees get older. HRM analysis has been used to identify "M.9" and "M.26" with simple sequence repeat (SSR) markers. Two SSR markers were highly informative and generated distinguishable curve profiles from HRM analysis. These markers would be efficiently and accurately utilized in breeding program targeting fruit skin color and cultivar identification with HRM analysis. [ABSTRACT FROM AUTHOR]

Very little is known about the mineral composition in the leaves of apple (Malus) rootstocks. Hence, in this study, variations in mineral composition were investigated among fourteen apple rootstocks (P.16, P.22, M.9, B.469, O.3, Mac.9, M.26, Pi.80, M.7, M.2, B.118, MM.11, M.25 and A.2) which have different growth vigor on a loamy soil in the stool bed conditions. Nitrogen (N) was determined by Kjeldahl method. Phosphorus (P) was analyzed using vanadate molybdate colorimetric method. Potassium (K), calcium (Ca), magnesium (Mg), manganese (Mn), iron (Fe), zinc (Zn) and copper (Cu) concentrations were determined using Inductively Coupled Plasma-Optical Emission Spectrometer (ICP-OES). The study results showed that the differences in mineral contents in leaves among apple rootstock genotypes were statistically significant. No problems were found in achieving adequate leaf N, P and Fe uptake of any rootstock. However, it was found to be lack of the K, Ca, Mg and Mn uptake in the majority of the rootstocks. Mac.9 rootstock, followed by B.469, showed high performance with in regard to the uptake of K, Ca and Mg. In general, the uptake of Fe, Ca and Mg of dwarf and semi-dwarf rootstocks were higher than those of vigorous rootstocks. Consequently, P.19, B.469, Mac.9 and M.26 rootstocks had adequate performances in the uptake of all macro and micro elements examined. [ABSTRACT FROM AUTHOR]

Grapevine can be infected by several viruses and viroids, the presence of which can lead to yield losses and vineyard decline. Our previous survey of vineyards in Hungary suggested that viral infection originates from infected propagation material. To investigate whether rootstocks can be a source of virus infections, we surveyed seventeen rootstock vineyards and two rootstock collections in Hungary to determine the virome by high-throughput sequencing of small RNAs. The presence of the viruses was also tested by RT-PCR. The results showed that viruses whose presence is routinely checked were almost absent in rootstock vineyards but were present in rootstock genotype collections. Moreover, first the time in Hungary, we detected the presence of Australian grapevine viroid in the rootstock genotype collection at Pecs. In contrast, viruses that are not regulated or not routinely tested, namely, grapevine rupestris stem-pitting-associated virus, grapevine Syrah virus-1 and grapevine Pinot gris virus, were detected in almost all locations in most of the varieties. The presence and absence of infected rootstock genotypes in the same vineyard together with phylogenetic analysis suggested that viral infections originated from infected propagation material. Moreover, we found the symptomatic variant of grapevine Pinot gris virus in several rootstock vineyards without symptoms, suggesting the possibility for leaf mottling and deformation disease symptoms to manifest on susceptible cultivars following grafting onto these rootstocks. [ABSTRACT FROM AUTHOR]

The experiment was conducted during 2016–2017 on Vitis vinifera cultivars (cv.) 'Superior Seedless', 'Razakı', 'Crimson Seedless', 'Sultana', 'Royal', and American rootstocks (41B, 1103P, 1616C, Ramsey, 5BB) at Department of Horticulture, Agriculture Faculty, Ege University, Turkey. This study was designed to investigate the effects of HWT on the quality of hard wood cuttings following the treatment. The hard wood cuttings that were hot water treated at 50 °C for 30 min which is the most common protocol against Agrobacterium vitis used worldwide. After HWT, cuttings (ungrafted) were planted in black polythene bags for rooting in greenhouse conditions. In this experiment, the effects of HWT on cuttings and root distribution (0–4 scala), root number, root length (cm), shoot length (cm), sprouting rate (%), rooting rate (%), fresh and dry root weight (g) were investigated. HWT was found to have variable effects on different characteristics of cultivar and rootstock cuttings. 41B saplings were negative affected from HWT for root distribution (0–4 scala), root number, shoot length (cm), sprouting rate (%), fresh and dry root weight (g). The HWT for 41B rootstock cuttings should be done carefully. 'Superior Seedless', 'Razakı' and 'Royal' were affected positively by HWT compared to non-HWT group cuttings for some criterians. [ABSTRACT FROM AUTHOR]

Evaluation of genetic diversity is the basis of any breeding programs in all plants. The aim of this study was to evaluate and investigate the morphological, ecophysiological and photosynthetic diversity of some Pistacia species which can be used in breeding programs. A total of 42 genotypes belonging to Pistacia atlantica Desf., P. mutica Fischer & C. A. Meyer, Pistacia vera L., Pistacia terebinthus L. and P. khinjuk Stocks species were studied. The results showed that the P. terebinthus species is more efficient than other species in terms of leaf weight, chlorophyll a and b and total chlorophyll, as well as chlorophyll fluorescence and photosynthesis efficiency index. Among the varieties of pistachio belonged to P. vera, 'Siirt' and 'Uzun' cultivars had the highest levels of chlorophyll a, b, and total, photosynthesis rate and transpiration. In addition, P. mutica species had the highest leaf phenol content and stomatal conduction. For most traits measured, the lowest value was observed in P. atlantica species. Moreover, the results showed that there was a positive and significant correlation between morphological and photosynthetic traits as well as morphological and ecophysiological ones so that, the leaf length had a positive and significant correlation with the quantum yield of photosystem II (Fv/Fm) (r = 0.87), the efficiency index of photosynthesis (pi) (r = 0.76), total chlorophyll (r = 0.92), and carotenoid (r = 0.91). Cluster analysis divided the genotypes into three distinct groups. The first group consisted of P. vera species and its genotypes plus P. khinjuk species. The second group included the species of P. mutica and P. atlantica, and the third one just consisted of the species of P. terebinthus. In general, the results of this study showed that P. terebinthus specie, as well as 'Akbari' and 'Siirt' cultivars from P. vera can be used as parents in breeding programs to improve the rootstocks and cultivars resistant to environmental conditions. [ABSTRACT FROM AUTHOR]

Aims: Vegetative groundcover and rootstock selection are popular growth control practices for fruit and nut crops. Theoretically, plant potential growth rate should influence competitive effectiveness; however, it is unclear if rootstock vigor alters crop productivity when groundcover is present. Methods: In a humid-climate vineyard we grew young grapevines on low- and medium-vigor rootstocks with and without groundcover. Vegetative growth was determined on dormant stems; yield was determined at harvest. Roots were extracted with soil cores and distribution, morphology, and mycorrhizal colonization were determined. Resource competition was assessed by water and nutrient depletion in vines and soil. Results: Compared to vines on low-vigor rootstocks, vines on medium-vigor rootstocks exhibited greater reductions in vegetative (40% vs 19%) and reproductive (22% vs 0%) growth by presence of groundcover. Irrespective of rootstock vigor, grapevine root systems coped with competition by increasing specific root length, decreasing absorptive root diameter, and redistributing roots deeper. Competition for nutrients was the apparent main cause of growth reductions with groundcover; however, mechanisms for differential rootstock responses remain unclear. Conclusions: This study suggests that in a wet year, young grapevines grafted on low-vigor rootstocks may be more tolerant of groundcover competition than those on medium-vigor rootstocks; however, both rootstocks cope with a similar root response. [ABSTRACT FROM AUTHOR]

In the conditions of the Czech Republic, a trial was conducted in 2012–2016 to evaluate the growth and yield of 16 spindle-grown plum varieties grafted on rootstocks St. Julien A, Wangenheim, Wavit and WaxWa. The trial was established in autumn 2005. As to the yield, 'Tophit' seems to be an interesting variety. This semi-prune reached high and regular fruit yields (44.1 kg/tree on average) on all rootstocks with the mean fruit weight of 60–70 g. The vigour of 'Valjevka' and 'Čačanska Rana' trees was significantly weakened by the Wangenheim rootstock compared to St. Julien A. At evaluating the mean fruit weight of 'Elena' and 'Tophit' varieties, a negative influence of the Wangenheim rootstock on this parameter was observed compared to St. Julien A. The mean fruit weight of the evaluated prunes and semi-prunes varieties ranged from 24.8 g at 'Top 2000' (Wavit) to 76.14 g at 'Čačanska Rana' (St. Julien A). A positive correlation was proved between trunk increment and fruit yield in the following year at all studied combinations of varieties and rootstocks; the strongest dependence was observed in plum trees on the Wavit rootstock. [ABSTRACT FROM AUTHOR]

The areas between Dagestan to Talysh, in the Trans-Caucasia and north of Iran are the central regions of quince (Cydonia oblonga Mill.) origin. Historic documents present evidences of quince domestication in the Mesopotamia, between 5000 and 4000 BC that have been pursued to about 500 BC in the ancient Persian and Greek empires. By the end of nineteenth century, domesticated populations of this plant had been spread to the west and east Asia, Europe and America which in turn, created several centers of diversity along its distribution route in some regions such as plateau of Iran, Anatolia, Greece and southern Europe, north of the Black Sea and Russia. Gradually in the mentioned domestication routes, selected quinces such as, Isfahan, Smyrna, Ekmek, Eşme, Vranja, Lescovatz and Champion have become commercialized as superior cultivars. Also genebank collections of the historic cultivars together with the promising genotypes of quince have been established in several countries including, Russia, Iran, Turkey, Greece, Italy, Bulgaria, Czech Republic, UK and USA. Investigations on morphological, molecular and horticultural characteristics of the germplasm have provided ample opportunities for application of advanced breeding programs especially to boost bearing potential, induce dwarfing, increase fruit quality and resistance to the main diseases such as fire blight. This review paper has attempted to give an account for quince historic origin, domestication, gene bank collections and breeding strategies. [ABSTRACT FROM AUTHOR]

Tissue culture and micrografting techniques are known as effective procedures to produce healthy rose rootstocks and high quality scions. In order to establish successful micrografting protocol for roses, several factors including different concentrations of Benzylamino-purine (BA) (0, 1, 1.5, 2 mg l−1) + 0.1 mg l−1 α-Naphthaleneacetic acid (NAA), sucrose concentrations (30, 50, 70 g l−1), types of grafting devices (aluminium foil, parafilm, paper bridge), and types of rose scions cultivars (Rosa hybrida cv. Red One, R. hybrida cv. Samurai) on two different types of native (Rosa canina) and commercial rose rootstocks (Rosa multiflora cv. Natal Briar) were examined. The high micrografting success (100%) was micrografting R. hybrida cv. Samurai scion on R. mutiflora cv. Natal Briar rootstock with the paper bridge as the best grafting device in the liquid Van der salm (VS) medium containing 2 mg l−1 BA + 0.1 mg l−1 NAA + 300 mg l−1 Casein Hydrolyzate + 2 g l−1 myo-inositol + 50 g l−1 sucrose. Treating the wounded explants (scions and rootstocks) with silver nitrate (50 mg l−1) during the micrografting process, increased the survival of micrografts. The micrografted plants were successfully rooted and well acclimatized. The present results provide the first efficient protocol to produce high successful micrografted rose plantlets in tissue culture. Key message: It is the first research protocol for micrografting of native and commercial roses by considering important factors relating to successful micrografting such as plant growth regulators, growth adjuvants, grafting devices, and medium ingredients. [ABSTRACT FROM AUTHOR]

Key message: Withholding irrigation at − 15 to − 25 kPa water potential significantly saved water with minimal changes in plant growth, water relations, and percentage of shippable citrus trees on drought-tolerant and -sensitive rootstocks.Abstract: We evaluated the impacts of regulated deficit irrigation (RDI) on plant growth, water relations, and biochemical variables of Valencia sweet orange nursery trees grafted on drought-tolerant Rangpur lime (RL) and drought-sensitive Swingle citrumelo (SC) rootstocks in pots. Irrigation was withheld to potting mix water potential of − 15 (mild RDI) and − 25 kPa (moderate RDI), with daily irrigation as control, in three graft growth periods (20-60, 61-120, and 20-120 days after grafting, DAG). Plant growth was reduced by moderate RDI, albeit RL induced more vigor than SC. SC induced higher CO2 assimilation rates and water use efficiency (WUE), regardless of the irrigation regime, and only trees grafted on RL decreased WUE under moderate RDI. Most leaf nutrient concentrations were increased with RDI intensity, while K levels were decreased by moderate RDI. Starch reserves were drastically decreased, while reducing sugars were increased by RDI in all plant organs, most notably in the leaves; roots represented the main source of carbohydrates for both rootstocks under water deficit. Starch concentration promptly recovered in all organs after restoring irrigation. Leaf proline concentration was 20 times higher at RDI, but decreased by 50% just 1 day after rehydration. Mild-to-moderate RDI resulted in water savings of 54-80%, but a 0-40% reduction in the percentage of shippable trees at 120 DAG; the biological responses were mainly related to the RDI duration. The production of container-grown citrus nursery trees in greenhouses could greatly benefit from the use of RDI, without major negative effects on tree quality. [ABSTRACT FROM AUTHOR]

Global warming, altering the physiology and irrigation demand of grapevines, has already been perceived in certain premium viticulture regions across the world. Selection of proper rootstocks for especially new cultivars has vital role for a sustainable viticulture under water-deficit conditions. The grapevine cultivar ‘Michele Palieri’ has been finding a good reception on the global markets. The objective of this study was to determine the response of ‘Michele Palieri’ cultivar to deficit irrigation using different rootstocks with distinct genetic origins. Two irrigation regimes (Full Irrigation [FI] and Deficit Irrigation [DI]) were applied to the vines of different grafting combinations of ‘Michele Palieri’ with Kober 5 BB, Richter 99, Richter 110, 140 Ruggeri, 44-53 Malégue or grown on own roots. Two years old vines were cultivated in 60 L pots containing sterile peat under controlled glasshouse conditions. Irrigations were regulated according to soil water matric potential (Ψm) levels using tensiometers. The volume of the irrigation water that has to be applied to attain 100% field capacity was performed as FI, while 50% of FI was considered as DI. The water was transported directly into the pots by micro-irrigation systems consisting of individual spaghetti tubes. The vines of DI treatment showed visible symptoms of mild water stress (e. g., loss of turgor in shoot tips), but no defoliation or leaf necrosis occurred. DI treatment reduced the gs of ‘Michele Palieri’ scion cultivar in varying levels depending on the rootstock. DI treatment also affected vegetative growth of the scion cultivar in different levels. For example, the greatest decrease (26.7%) in shoot length resulting from DI was determined in ‘Michele Palieri’/5 BB grapevines, followed by own rooted vines (13.1%), while the lowest change (2.4%) was found in vines grafted on 110 R. Overall findings of this study imply that the rootstocks originating from V. berlandiery × V. rupestris hybrids (110 R, 99 R, 140 Ru and 44-53 M) better performed in a similar genetic aptitude under deficit irrigation regime while the rootstock 5 BB (V. berlandiery × V. rupestris) showed more susceptible responses. On the other hand, the general response of own rooted vines were better than those grafted on 5 BB. Therefore, the use of one of V. berlandiery × V. rupestris hybrids may be a better choice for viticulture under semiarid regions. [ABSTRACT FROM AUTHOR]

Tomato landrace producers are adopting grafting technology to overcome agronomic deficiencies and increase plant yields. Landraces are valued for their higher organoleptic quality, so it is important to assess the impact of grafting on their sensory profile. We studied the influence of ‘Beaufort’ rootstock on agronomic, morphologic, and sensory traits using two landraces (‘Mando’ and ‘Montgri’) and one commercial cultivar (‘Egara’) as scions in two extreme management systems for tomato cultivation: conventional/greenhouse and organic/open field. Panel sensory analysis found that grafting onto ‘Beaufort’ had a negative effect on sensory attributes, reducing sweetness, acidity, and intensity of flavor in the organic system and sweetness and intensity of flavor in the conventional system. In conventional management, grafting also modified some aspects of fruit appearance. In the conventional system, grafting significantly increased yield in all the genotypes (mean increase, 52%). By contrast, in the organic system, grafting increased yield only in the ‘Mando’ landrace (mean increase, 62.3%). As many genotype × grafting interactions affecting many important commercial traits occurred in both management systems, specific studies with different rootstock-scion combinations are highly recommended before adopting this technique for producing landraces with high sensory quality. [ABSTRACT FROM AUTHOR]

Key message: The study has unraveled the genetic relationship of under-utilised citrus varieties with rough lemons and found new insights into the development of suitable rootstocks for promoting citriculture in North-East India.Abstract: Citrus resources of North-East India represent an invaluable source of various agronomic traits to breed new cultivars and rootstocks having adaptability to the agro-climatic conditions of the region. Lack of scientific approaches and resources towards identification and conservation of unique varieties of Citrus, destruction of natural habitats and absence of adequate information on the genetic relationship of existing citrus forms have resulted in the decline of citrus diversity in NE India. A total of 18 citrus genotypes of rough lemon strains and other under-utilized Citrus spp. collected from the region have been characterised using 22 SSR and 29 RAPD markers. The markers grouped the citrus genotypes into clusters of rough lemon, an acidic citrus group of lemon or natural hybrids and a small cluster of three genotypes. Polymorphic information content values of the SSR markers ranged from 0.481 to 0.90 and 0.26 to 0.45 in the case of RAPD markers. Similarity coefficient value ranged from 0.504 to 0.855 in RAPD while it varied from 0.299 to 0.723 in the case of SSR. C. assamensis along with two other Citrus genotypes grouped with a rough lemon cluster in SSR while shows genetic affinity with the acidic citrus group in RAPD analysis. Citrus indica was observed to be genetically distant from other citrus groups in both the marker systems studied. Grouping of related citrus forms and study of their genetic relationship will be of immense value for conservation and utilization of the region’s rich citrus resources. [ABSTRACT FROM AUTHOR]

We assessed different rootstocks and grafting techniques to clonally propagate mastic tree (Pistacia lentiscus var. chia). Mastic tree is a dioecious tree but the quantity and quality of the resin secreted by female trees are very low; therefore, male trees that are clonally propagated are used to establish commercial plantations for mastic production. Conventional long branch cuttings for clonal production requires too much materials and has a very low rooting rate. Rooting with tissue culture and green cuttings has also failed outdoors. Grafting of mastic on other Pistacia species has not been tried so far; therefore, this study was aimed at developing grafting methods for the clonal propagation of mastic. P. atlantica and P. lentiscus rootstocks were grafted from 15 February to 15 October every 15 days using three grafting methods and a two-factor randomized block trial design. Early spring (15 February-15 March) proved to be the best time for grafting using either of the rootstocks. The highest grafting success was attained using the scions grafted on P. atlantica from 15 February to 15 March. The best bud-burst percentage was obtained using P. atlantica and P. lentiscus rootstocks. [ABSTRACT FROM AUTHOR]

Grafting has been a long-standing technique used to improve crop production and provide tolerance to biotic stresses, including soil-borne pathogens, as well as tolerance to abiotic stresses, such as cold, salinity, drought, and heavy metals. Currently, beyond its use in horticultural production, grafting has received great prominence as an important research tool, mainly regarding signaling mechanisms related to root-shoot communication. Most of the emphasis from recent studies has been on detection of the long-distance transport of molecules and signaling factors, especially phytohormones, RNAs, peptides, and proteins. Through these studies, there have been significant breakthroughs about the underlying mechanisms implicated in the regulation of developmental and stress responses at the whole plant level. Because of this, the aim of this paper is to provide an overview of grafting as an important tool for plant science. Thus, in the following sections, we will summarize what is most recent and relevant in the use of grafting in plant research. [ABSTRACT FROM AUTHOR]

Tomato production is limited in Nigeria by foliar and soil-borne diseases. Most cultivars that command a premium market are susceptible to bacterial wilt disease caused by Ralstonia solanacearum. Tomato growers need researches that support the advantages of market niches afforded by these tomatoes through the development of systems to manage diseases against loss of yields. Bacterial wilt, the major soil-borne disease in the southwestern Nigeria, was effectively managed using susceptible tomato cultivars Beske and UC82-B grafted onto resistant rootstock (cv. Tomachiva). The experiment was laid down in a randomized complete block design. Grafted cv. Beske was not affected by bacterial wilt disease both in early and late planting season, respectively. However, non-grafted cvs Beske and UC82-B experienced various degrees of disease incidence and severity ranging from 36.70% to 50% in cv. Beske, 31.70% to 35% incidence in cv. UC82-B and were significantly higher (P < 0.05) than 0% incidence in cv. Beske and 0-3.30% incidence in cv. UC82-B in both early and late planting seasons, respectively. There was significant increase (P ≤ 0.05) in yield of grafted cv. Beske up to 63.16% and 53.38% in early and late planting seasons, respectively. Grafted cv. UC82-B had 56.14% and 71.76% yield increase in early and late planting seasons, respectively. Consistent numeric and tonnage increase in fruit yield were observed in grafted tomato plots which were significantly higher (P ≤ 0.05) than in non-grafted tomato plots. In conclusion, grafting is an effective management tool for tomato growers in the southwest Nigeria to reduce risk of crop loss resulting from soil-borne diseases and could be a valuable component in an integrated pest management program. [ABSTRACT FROM AUTHOR]

Rootstocks-scion relations have critical consequences about nutritional status, tree vigour, resistance to pest and pathogens, yield and yield quality. In this study, we therefore investigated seasonal variations of leaf mineral nutrient concentrations in Satsuma mandarin’s cvs. ‘Okitsu’, ‘Clausellina’ and ‘Silverhill’ budded on different citrus rootstocks under Dörtyol-Hatay, Turkey ecological conditions. Nitrogen (N), phosphorus (P) and K (potassium) concentrations of the leaves showed slightly similar trend each other, in general these nutrients reduced from January to March–April, and increased during the growing season until mid- and late summer, then decreased until December. Despite rootstocks did not significantly affect the leaf N, P and K concentrations rootstock-scion relation was pre-eminent and nutrient dependent. Most conspicuous scion dependent changes were recorded for K concentration whereas P concentration was little influenced. In terms of scion-rootstock combination, the range of N and K concentrations were 2.11% (‘Okitsu’/sour orange) to 2.34% (Silverhill/sour orange), and 1.09% (‘Okitsu’/Carrizo citrange) to 1.39% (‘Clausellina’/Carrizo citrange), respectively; but P concentrations were highly similar %0.13 (‘Okitsu’/sour orange) – %0.16 (‘Clausellina’/Carrizo citrange), in the entire growing season. It can be concluded that there are considerable differences in nutrient uptake ability of scion-rootstock combination. [ABSTRACT FROM AUTHOR]

Tolerance to water deficit in diploid (2 x) and doubled diploid (4 x) 'Carrizo citrange' ( Citrus sinensis [L.] Osbeck × Poncirus trifoliata [L.] Raf) was investigated. Water deficit was applied for 4 weeks. Physiological parameters, including stomatal conductance ( g ), photosynthesis ( A), transpiration ( E), leaf and soil water potentials ( Ψ ; Ψ ), and pot water loss, were monitored throughout the stress. Moreover, ABA, HO contents, and the expression of genes involved in ABA biosynthesis ( NCED3), regulation of abscisic acid signaling ( ABI1), and coding for a catalase enzyme ( CAT2) known to favor HO scavenging were monitored. During the experiment g , A, and E values were most of the time higher in 2 x compared to 4 x. During the water deficit period, pot water loss decreased faster in 2 x compared to 4 x, leading to a faster decrease in all physiological parameters in 2 x. The higher sensitivity of 2 x compared to 4 x was correlated with more numerous thinner roots, higher leaf ABA and HO contents, and with the lower leaf water potential. ABI1 and NCED3 expression was not strictly correlated with the ABA content. However, the higher CAT2 expression in 4 x was correlated with the lower leaf HO contents. Therefore, the better tolerance observed in 4 x 'Carrizo citrange' compared to 2 x was associated with more limited water consumption and better and HO scavenging. [ABSTRACT FROM AUTHOR]