Non-grafted Plants Research Articles

A One-Step Grafting Methodology Can Adjust Stem Morphology and Increase THCA Yield in Medicinal Cannabis

The standard two-step methods for grafting horticultural crops involve cultivating the rootstock for a period of time and then connecting the scion. Medicinal Cannabis differs from most annual horticultural crops because it is usually clonally propagated from cuttings. We developed a grafting methodology specifically for medicinal Cannabis, involving a single step, in which a freshly cut scion is grafted to a freshly cut donor stem that will become the rootstock. This study also aimed to uncover a potential role for roots in influencing cannabinoid content. Two varieties with desirable attributes but cultivation limitations were selected to act as scions. The first, “CBD1” was a high CBDA accumulating variety with low biomass yield, and the second, “THC2”, was a high yielding, high THCA accumulating line with inconsistent root development during cloning. Two candidate rootstocks, “THC9r” and “THC8r”, were identified; both were high THCA, low CBDA varieties. Biomass yields in the THC2 scions grafted to THC9 rootstocks (THC9r_2s) were 20% higher than in the non-grafted THC2 plants. In CBD1 grafted plants, the concentrations of CBDA and some minor cannabinoids were significantly different to non-grafted CBD1, but biomass yields were lower. There was a trend towards a higher concentration of THCA in THC9r_2s plants, and when combined with the increased biomass, yield of THCA was increased from 8 g Plant−1 to 13 g Plant−1. Our results present a new grafting method for medicinal Cannabis that improved yield in THC2 and required no additional cultivation time.

Effect of Graft and Nano ZnO on Nutraceutical and Mineral Content in Bell Pepper.

The objective of this experiment was to evaluate the effects of grafting, zinc oxide nanoparticles (ZnO NPs), and their interaction on the nutritional composition of bell pepper plants. The treatments evaluated included grafted and non-grafted pepper plants with four concentrations of ZnO NPs (0, 10, 20, 30 mg L−1) applied to the foliage. The following parameters were evaluated: content of N, P, K+, Ca2+, Mg2+, Mn2+, Zn2+, Fe2+, Cu2+, total antioxidants, ascorbic acid, total phenols, glutathione, total proteins, fruit firmness, and total soluble solids. Grafting increased the content of N 12.2%, P 15.9%, K+ 26.7%, Mg2+ 20.3%, Mn2+ 34.7%, Zn2+ 19.5%, Fe2+ 18.2%, Cu2+ 11.5%, antioxidant capacity 2.44%, ascorbic acid 4.63%, total phenols 1.33%, glutathione 7.18%, total proteins 1.08%, fruit firmness 8.8%. The application of 30 mg L−1 ZnO NPs increased the content of N 12.3%, P 25.9%, Mg2+ 36.8%, Mn2+ 42.2%, Zn2+ 27%, Fe2+ 45%, antioxidant activity 13.95%, ascorbic acid 26.77%, total phenols 10.93%, glutathione 11.46%, total proteins 11.01%, and fruit firmness 17.7% compared to the control. The results obtained demonstrate the influence of the use of grafts and ZnO NPs as tools that could improve the quality and nutrient content in fruits of bell pepper crops.

Eggplant grafting on a cold-tolerant rootstock reduces fruit chilling susceptibility and improves antioxidant stability during storage.

Vegetable grafting has been increasingly evaluated to improve preharvest tolerance to biotic and abiotic stresses. However, very few studies have identified rootstock-scion combinations able to improve fruit shelf life and reduce the susceptibility to postharvest disorders. Herein, a purple eggplant scion (cv. Monarca) was grafted onto a cold-tolerant hybrid Solanum rootstock ('Java') and the changes in growth, quality, postharvest chilling tolerance, and antioxidant stability were evaluated. Eggplant grafting enhanced plant vigor and fruit growth rate, decreasing the time from set to harvest by 10-15%. Grafted eggplants had a thinner shape and lighter pulp color than the control. The rootstock-scion combination tested showed lower respiration (~60%), dry matter (~15-20%), and phenolic compounds contents (~15-20%) than eggplants from non-grafted plants. Grafting markedly improved fruit performance during postharvest storage. Remarkably, grafted eggplants showed much higher tolerance to chilling injury than the control did, evidenced by a reduction of surface scalds along with decreased softening and pulp browning. The trend in antioxidants found at harvest time was reversed after cold storage due to enhanced stability (20% and 100% for pulp and peel respectively) in fruit from grafted plants. Purple eggplant (cv. Monarca) grafting onto 'Java' hybrid rootstock modulated fruit growth, quality at harvest, and increased fruit chilling injury tolerance during storage. Grafting may be a bona fide strategy to induce phenotypic traits able to improve vegetable postharvest performance. © 2021 Society of Chemical Industry.

Flowering Time and Productivity of Interspecific Grafts Between Pepper Species in Contrasting High Tunnel-sheltered and Open-field Production Environments in Costa Rica

The production of sweet peppers (Capsicum annuum) is often constrained in tropical environments by susceptibility to persistent soil-borne diseases, including bacterial wilt (Ralstonia solanacearum). However, the production of sweet peppers in high tunnels using sterile soilless media irrigated with nutrient solution offers the potential to reduce the incidence of bacterial wilt. An additional strategy for disease management is the use of sweet pepper scions grafted onto rootstocks that are resistant to soil-borne pathogens. Two sweet pepper cultivars grown extensively in the tropics, Nathalie and 4212, were used as scions and grafted onto the habanero pepper cultivar Habanero TEC (Capsicum chinense) and the aji pepper cultivar Baccatum TEC (Capsicum baccatum). Two cultivars related to the two rootstocks were prescreened for susceptibility to two virulent strains of bacterial wilt. Graft combinations were grown in two environments, a high tunnel with automatic nutrient solution irrigation of containers filled with sterile coconut fiber and an open field with known high levels of bacterial wilt inoculum. Self-grafted and nongrafted plants of scions were included as checks. The disease susceptibility screening showed that the area under the disease progress curve was consistently low for ‘Habanero TEC’ and ‘Baccatum TEC’ when inoculated with two virulent strains of bacterial wilt, suggesting that habanero pepper cultivars and, to a lesser degree, aji pepper cultivars may be useful as rootstocks in soils with bacterial wilt inoculum. Significant increases in yield, fruit number, and reduced time to flowering were observed in the high tunnel compared with the open-field environment. Individual fruit weight was reduced in the high tunnel compared with the field. Yield, fruit number, fruit weight, and time to flowering were consistent between scions regardless of rootstock. No differences were observed for yield, fruit number, fruit weight, or time to flowering of self-grafted and nongrafted scion checks. In the high tunnel, yield was higher in scions grafted onto ‘Habanero TEC’ compared with self-grafted and nongrafted checks. In the open field, yield and fruit number were highest on scions grafted onto ‘Habanero TEC’. Regardless of graft treatment, high-tunnel production in tropical environments can result in significant increases in yield and fruit number compared with open-field production. No advantage of grafted plants was observed in the high-tunnel production environment. In contrast, in the open-field environment, grafting sweet pepper scions onto pungent habanero rootstocks resulted in a significant increase in yield, fruit number, and fruit size compared with self-grafted and nongrafted checks. The increase was likely attributable to the resistance of habanero pepper cultivars to soil-borne diseases, including bacterial wilt.

Enhanced Drought Tolerance of Arabica Coffee (Coffea arabica L.) by Grafting Method

The objective of this study was to evaluate grafting method to improve the drought tolerance of Coffea arabica. Using C. arabica species as scions, and C. robusta as rootstock, the grafted plant was compared with the non-grafted plant (C. arabica) under water deficit condition. The result shown that growth parameters such as plant height, leaf length, and leaf width of the grafted coffee plants were higher than those of the non-grafted. The leaf area, fresh and dry weight of plants were highly reduced in non-grafted coffee plants. The leaf chlorophyll content (SPAD) and chlorophyll fluorescence (Fv/Fm) values of the grafted and non-grafted coffee plants decreased significantly with increasing duration under water deficit condition. The SPAD and Fv/Fm values of the two coffee types were also increased significantly with increasing duration after re-watering. Compared to the non-grafted plants, higher values of SPAD, Fv/Fm and relative water content in the leaf were observed in the grafted coffee plants. Moreover, lower values of relative ion leakage were observed in the grafted coffee plants after three days of water withholding and one month after re-watering. On the other hand, the grafted coffee plants showed enhanced drought tolerance by reducing the percentages of wilting plant under water deficit condition, and increasing the recovery percentages after re-watering.

Ефективність сорто-підщепних комбінувань нових індетермінантних гібридів F1 помідора за вирощування способом малооб’ємної гідропоніки у скляних теплицях

Goal. To determine the efficiency of rootstock combinations on new indeterminate hybrids F1 of tomato at growing by the method of low volume hydroponics in glass greenhouses of the «Venlo» type. Methods. Laboratory and production experiments, visual — to carry out phenological observations; measuring — to determine the biometric parameters and yield of tomato; analytical — to determine quality indicators; statistical — to establish the reliability of experiments. Experiments on the study of three indeterminate hybrids of tomato Torero F1, Barteza F1, and Merlis F1 with grafting on rootstocks Maxifort F1, TD1 F1, and Emperador F1 were carried out by the method of low-volume hydroponics in greenhouses of «Venlo» type (PJSC «Teplychnyi»). Results. It was found that the use of tomato rootstocks Maxifort F1, TD1 F1, and Emperador F1 helped to increase early yields in all variants. Significantly higher yields compared to non-grafted plants in all years of research were obtained in the hybrid Torero F1 on the rootstock TD1 F1 (30.4 kg/m2), in the hybrid Barteza F1 on the rootstock Emperador F1 (30.53 kg/m2), in the hybrid Merlis F1 on the rootstock Emperador F1 (31 kg/m2). The use of rootstocks provided an increase in total yield at the level of 3.9–7.6%. For the Torero F1 hybrid the best rootstocks were TD1 F1 (65.2 kg/m2) and Emperador F1 (65.5 kg/m2), for Barthez F1 — Maxifort F1 (63.0 kg/m2) and Emperador F1 (63.6 kg/m2), for Merlis F1 — Emperor F1 (67.8 kg/m2). Conclusions. For growing tomatoes of hibrid F1 in modern block hydroponic winter greenhouses of the «Venlo» type, to increase the share of early yield (as of July 10) at the level of 30.4–31.0 kg/m2 and the total yield at the level of 63.6–67.8 kg/m2 with high fruit biochemical parameters, it is recommended to use the following rootstock combinations: Torero F1/TD1 F1 or Emperor F1; Barteza F1/Emperor F1, or Maxifort F1; Merlis F1/Emperor F1.

Effect of Cold Stress on Growth, Physiological Characteristics, and Calvin-Cycle-Related Gene Expression of Grafted Watermelon Seedlings of Different Gourd Rootstocks

Recently, grafting has been used to improve abiotic stress resistance in crops. Here, using watermelon ‘Zaojia 8424’ (Citrullus lanatus) as scions, three different gourds (Lagenaria siceraria, 0526, 2505, and 1226) as rootstocks, and non-grafted plants as controls (different plants were abbreviated as 0526, 2505, 1226, and 8424), the effect of cold stress on various physiological and molecular parameters was investigated. The results demonstrate that the improved cold tolerance of gourd-grafted watermelon was associated with higher chlorophyll and proline content, and lower malondialdehyde (MDA) content, compared to 8424 under cold stress. Furthermore, grafted watermelons accumulated fewer reactive oxygen species (ROS), accompanied by enhanced antioxidant activity and a higher expression of enzymes related to the Calvin cycle. In conclusion, watermelons with 2505 and 0526 rootstocks were more resilient compared to 1226 and 8424. These results confirm that using tolerant rootstocks may be an efficient adaptation strategy for improving abiotic stress tolerance in watermelon.

High Tunnel Production of Containerized Hybrid and Heirloom Tomatoes Using Grafted Plants with Two Types of Rootstocks

Tomatoes (Solanum lycopersicum) are not only one of the most widely grown and consumed vegetables in the U.S., but are also one of the most economically important vegetables for Mississippi growers operating on small- to medium-sized farms. High tunnel production and vegetable grafting serve as effective approaches to provide season extension and improve productivity and resistance to a number of abiotic and biotic factors for tomato plants. Six tomato cultivars, including three hybrids (‘Big Beef’, ‘Early Girl’, and ‘Sun Sugar’) and three heirlooms (‘Brandywine’, ‘Mortgage Lifter’, and ‘San Marzano’), were evaluated for plant growth, fruit yield, and quality in a containerized high tunnel production system in 2020. Each cultivar was grafted onto two types of interspecific hybrid rootstocks ‘Emperador’, or ‘Maxifort’, or grown non-grafted as control. ‘Big Beef’ and ‘Early Girl’ produced comparable highest marketable yields of 9.62 to 11.12 kg per plant, compared with ‘San Marzano’ and ‘Sun Sugar’ producing the lowest marketable yields of 3.27 to 4.76 kg per plant due to small fruit sizes. Grafting the selected tomato cultivars with the two rootstock types did not alter total marketable yield of any cultivar, but affected overall stem diameter, fruit color, and β-carotene concentrations. The rootstock ‘Emperador’ decreased soluble solids content and titratable acidity in ‘Early Girl’ compared to ‘Maxifort’ grafted or non-grafted plants. The high tunnel enabled early transplanting and resulted in advanced tomato harvest by approximately three to four weeks compared to local field production.

Grafting effect on photosynthetic activity and yield of tomato under a plastic house in Colombia

Grafting is an effective approach to improve tomato yield and for tolerance to various abiotic and biotic stresses. This technique consists of using a vigorous or resistant plant (rootstock) to replace the root system of a genotype of economic interest (scion) but susceptible to one or more stress factors. The present work aimed to evaluate the physiological and productive response of a commercial tomato scion grafted on different rootstocks in Colombia’s high-Andean region. For this purpose, a tomato cv. Libertador was grafted on two commercial (“Olimpo” and “Armada”) tomato rootstocks in a randomized complete block experimental design. Four scion×rootstock combinations were evaluated by vigor rootstock, resistant rootstock, self-grafting, and non-grafted plants. Net photosynthesis, transpiration rate, stomatal conductance, water use efficiency, and radiation use efficiency were evaluated during six phenological stages (701, 704, 706, 708, 710, and 712), according to the BBCH scale; while the leaf area index and quantum yield were analyzed in five phenological stages (except 706). The highest values of photosynthesis, stomatal conductance, water and radiation use efficiency were registered in the initial phase of the production stage (701), which tended to decline at the end of the life cycle (712). Transpiration rate was similar throughout the growth cycle. Nevertheless, vigor rootstock presented the lowest photosynthesis rate; it was superior in terms of leaf area index, leaves dry matter, and tomato yield. The quantum yield values of the photosystem II did not indicate photochemical injuries in any of the scion×rootstock combinations. The higher tomato yield was reached in vigor rootstock and was associated with a more significant accumulation of dry matter in the leaf and higher leaf area index.

Impact of different rootstocks and limited water on yield and fruit quality of melon grown in a field naturally infested with Fusarium wilt

1- Grafting and rootstock-scion combinations affect fruit yield. 2- The yield increased with increasing the mean fruit weight, yield per plant and number of fruits per plant. 2- Grafting plants had a significant positive effect on fruit quality. 3- The mineral concentrations of melon-grafted plants are higher than those of non-grafted plants throughout the growth period. 4- The low soil moisture and not to graft for Fusarium wilt disease promotes the growth of the pathogen and the emergence of wilt symptoms. The experiment was performed to determine the effects of different rootstocks on yield and some fruit quality characteristics of grafted melon growth under the soil-borne pathogen ( Fusarium oxysporum f.sp.melonis ) and water stress conditions in 2019-2020, at Cumra in Konya Plain, Turkey. In the study, four different Cucurbita maxima x Cucurbita moschata hybrids rootstocks were used: 1-Non-grafted, 2-Ferro, 3-Maximus, and TZ 148. Edalı F 1 variety ( Cucumis melo var. Edalı F 1 ) was selected as a scion. Cotyledon splice grafting was used as the grafting method. The experiment was conducted in a split-plot design with three replications. The main plots constituted of three irrigation levels while the subplots were designed to have different rootstocks. Irrigation was supplied during the appropriate crop development stages (early vegetative, late vegetative, flowered-fruit setting and ripening) with enough water to fill the soil depth of 0–90 cm to field capacity (I100), to 50% of field capacity (I50) with decreased water supply levels and water-free (I0) conditions. As a result, it was found that yield and some fruit quality parameters were significantly affected by the treatments. The rootstocks were similarly effective on soil-borne pathogen management and resulted in yields higher than non-grafted plants in the both years. The highest yield (4.939–3.604 t da−1) was obtained under no water stress I100 / TZ148 rootstock combination (p<0.01). Other macro-micro nutrient and fruit sugar contents were significantly affected by treatments. The seasonal water consumptive use (ET) at I100 treatment was recorded as 205 and 231 mm, respectively, for the both years.

Combined Influence of Grafting and Type of Protected Environment Structure on Agronomic and Physiological Traits of Single- and Cluster-Fruit-Bearing Cucumber Hybrids

Protected vegetable cultivation is a fast-growing sector in which grafting plays a crucial role for success. Cucumber is predominantly grown under protected conditions. The popular slicing (mini) cucumber comprises two segments, single- and cluster-fruit-bearing. In the present study, the performance of select fruit-bearing hybrids grafted as scions onto commercial Cucurbita hybrid rootstock ‘NS-55’ was evaluated under three different low-cost protected structures in arid regions. With respect to type of protected structure, cucumber performance was superior under a naturally ventilated polyhouse (NVP) than an insect net house (INH) or a shade net house (SNH). Micro-climate parameters inside NVP (air temperature, RH and PAR) were more congenial for cucumber than those in net houses, thereby facilitating improved physiology (chlorophyll fluorescence, chlorophyll and plant water potential) and leaf mineral status. Grafting invariably improved growth and yield parameters under all protected structures. Overall plant performance was better in the grafted cluster-fruit-bearing hybrid ‘Terminator’ than the single-fruit-bearing hybrid ‘Nefer’ or their non-grafted counterparts. Furthermore, NVP was found to be superior to net houses for water productivity, and grafted plants were more water use efficient than their counterpart non-grafted plants. Thus, NVP can be considered a suitable low-cost protected structure in conjunction with grafting to boost cucumber crop and water productivity in arid regions.

Performance of Grafted and Non-Grafted Cantaloupe Plants Undergo Different Fertilization Rates of Nitrogen, Phosphorus, and Potassium

pagation of cucurbits via grafted seedlings exhibits an increasing trend in vegetable cultivation in Egypt. This is due to the limited cultivated area, intensive cultivation, and increasing stress leading to problems that negatively affect production. While the investigations for determining the accurate fertilization amount of the grafted plants are still scarce. Therefore, this experiment was conducted in a private farm located in Badr city, El-Behera governorate, Egypt, to evaluate the performance of non-grafted (control) and grafted cantaloupe plants (Cucumis melo var. cantaloupenses, cv. Marella F1 hybrid) onto four rootstock cultivars (Cobalt, Ferro, Star, and 6001) then fertilized with nitrogen (N), phosphorus (P), and potassium (K) at rates of 60, 80, 100, 120, and 140% of these nutrients recommendations for cantaloupe fertilization during the two successive growing seasons of 2018 and 2019. The results indicated that grafting cantaloupe plants onto the tested rootstocks had promoted a higher vegetative growth manifested as plant length, leaves number, shoot fresh and dry weight, stem diameter, and root dry weight, as well as raising leaves content of nitrogen, phosphorus, potassium, and the greenness index (chlorophyll readings, SPAD) along with boosting the average fruit weight, and early and total yield than the control when all were fertilized by any of the applied fertilization rates. Worthy, rootstocks of Cobalt and Ferro provided the greatest superiority in all investigated growth and fruit yield characteristics of the cantaloupe plant through fertilizing by the 140% NPK fertilization rate.

Productive Characteristics and Fruit Quality Traits of Cherry Tomato Hybrids as Modulated by Grafting on Different Solanum spp. Rootstocks under Ralstonia solanacearum Infested Greenhouse Soil

Grafting is increasingly becoming an indispensable tool that minimizes the risks associated with intensive vegetable production systems, including soil-borne diseases. This study assesses the performance of two cherry tomato hybrids (‘Cheramy’ and ‘Sheeja’) grafted onto three tomato and five eggplant local rootstock genotypes (cultivated/wild) under Ralstonia solanacearum (bacterial wilt)-infested greenhouse soil. The impact of grafting on growth, yield and fruit physical quality was mainly influenced by the response of rootstocks to disease resistance. The non-grafted plants of both the cultivars were severely affected by bacterial wilt, thus presenting high susceptibility to disease. Eggplant rootstocks imparted moderate to high resistance against bacterial wilt in both the scions, while tomato (cultivated or wild) rootstocks did not improve disease resistance, except ‘Anagha’, which provided resistance to scion cv. ‘Cheramy’. In general, scion cv. ‘Cheramy’, grafted or non-grafted, showed superior growth, yield and fruit quality compared to ‘Sheeja’. The most productive graft combinations for both the cultivars involved resistant rootstocks, i.e., ‘Sheeja’ onto eggplant rootstock ‘Surya’, and ‘Cheramy’ onto tomato rootstock ‘Anagha’. Fruit quality attributes such as ascorbic acid and lycopene contents were considerably higher, and the total soluble solids (TSS) content was considerably lower in scion cv. ‘Cheramy’, whether grafted or non-grafted, than those involving scion cv. ‘Sheeja’. The grafting effect on fruit chemical quality attributes was not promising, except grafting ‘Sheeja’ onto ‘Sopim’ for TSS, ‘Sheeja’ onto ‘Sotor’ for lycopene and ‘Cheramy’ onto ‘Ponny’ for total phenols, though no clear connection with disease incidence was in these grafts. Conclusively, eggplant rootstock imparted wilt resistance, while both eggplant and tomato rootstock grafting was beneficial to both scion cultivars in boosting the overall production and economic gains, especially for ‘Cheramy’ grafted onto ‘Anagha’ rootstock under bacterial wilt infested soil of greenhouse.

On-Farm Evaluations of Anaerobic Soil Disinfestation and Grafting for Management of a Widespread Soilborne Disease Complex in Protected Culture Tomato Production.

Tomato production in Ohio protected culture systems is hindered by a soilborne disease complex consisting of corky root rot (Pyrenochaeta lycopersici), black dot root rot (Colletotrichum coccodes), Verticillium wilt (Verticillium dahliae), and root-knot (Meloidogyne hapla and M. incognita). In a survey of 71 high tunnels, C. coccodes was detected in 90% of high tunnels, and P. lycopersici (46%), V. dahliae (48%), and Meloidogyne spp. (45%) were found in nearly half of high tunnels. Anaerobic soil disinfestation (ASD) with wheat bran (20.2 Mg/ha) plus molasses (10.1 Mg/ha) and grafting onto 'Maxifort' or 'Estamino' rootstocks were evaluated in high tunnels on five farms. In post-ASD bioassays of trial soils, root and taproot rot severity were significantly reduced after ASD, and root-knot galling was also reduced by ASD. Soilborne pathogenic fungi were isolated less frequently from bioassay plants grown in ASD-treated soils than control soils. Similar results were observed in tomato plants grown in high tunnels. Root rot was significantly reduced by ASD in nearly all trials. Corky root rot severity was highest in nongrafted plants grown in nontreated soils, and the lowest levels of corky root rot were observed in 'Maxifort'-grafted plants. Black dot root rot severity was higher or equivalent in grafted plants compared with nongrafted plants. Root-knot severity was lower in plants grown in ASD-treated soils in high tunnels compared with plants grown in control soils, but grafting did not significantly decrease root-knot severity. However, soil treatment did not significantly affect yield, and grafting led to inconsistent impacts on yield.

Foliar application of zinc oxide nanoparticles and grafting improves the bell pepper (Capsicum annuum L.) productivity grown in NFT system

The bell pepper (Capsicum annuum L.) is a food vegetable with a high nutritional intake, with rich content in vitamins, minerals and antioxidants. In this study, using nutrient film technique (NFT) system, the effect of the zinc oxide nanoparticles on the micromorphology, histology, physiology and production of the grafted pepper was evaluated. The treatments used were grafted and non-grafted plants, four concentrations (0, 10, 20, 30 mg L-1) of zinc oxide nanoparticles, and the experience was organized in a completely randomized design. An increase in grafted plants was observed in the weight, number and size of fruits in 18.1%, 21.8% and 9.6%, the concentration 30 mg L-1 of nanoparticles statistically affected the weight, number and size 46.9%, 47.7% and 18% compared to the control. The interaction with grafted plants and the treatment of 30 mg L-1 of zinc oxide nanoparticles increased fruit weight, number of fruits and size by 62.60%, 57.69% and 29.17% compared to plants without grafting and the control treatment. These results indicate that the use of grafts and zinc oxide nanoparticles could be used in bell pepper production to increase yield.

The Efficacy of Grafting on Alkali Stressed Watermelon Cultivars Under Hydroponic Conditions

The goal of the present study was to determine whether grafting of watermelon on gourd rootstocks could improve alkalinity tolerance and to investigate the physiological and morphological response mechanisms of the grafted plants under different pH levels. The experiment was carried out in a climate chamber to investigate growth, leaf chlorophyll content (SPAD), leaf area, stem length, shoot and root dry weight, root length, electrolyte leakage, leaf mineral composition, total chlorophyll and carotenoid contents. Two watermelon cultivars (Crimson tide, CT, and Crisby) were grafted onto three commercial Cucurbita maxima × C. moschata hybrid rootstocks under climate-chamber conditions (Strong tosa, ST, Ercole and Nun 9075). The grafted seedlings were transplanted onto 8 L continuously aerated pots containing nutrient solution with two different pH levels (8.5 and 6.5) and replicated three times. The results showed that in both grafted and non-grafted plants, there was a substantial reduction in shoot and root biomass production at high pH levels. At high pH level, the significantly highest leaf area, stem length, SPAD, concentration of P, Ca, S and Mn in leaf tissues were recorded in graft combination ‘Crisby/Ercole’, whereas the significantly highest concentration of Fe in leaf tissues, shoot dry weight were recorded in graft combination ‘Crisby/Nun 9075’. Moreover, at high pH, the significantly highest concentration of Mg and Cu in shoot under high pH levels was significantly found in graft combination of ‘CT/ST’. These results suggest that the use of interspecific Cucurbita maxima × C. moschata hybrid rootstocks can improve crop performance in watermelon plants under alkaline conditions.

Root-growth Characteristics Contributing to Nitrogen Efficiency of Reciprocally Grafted Potatoes (Solanum tuberosum L.) Under Hyroponic Conditions

To assess whether grafting could improve the nitrogen (N) efficiency of potato cultivars and to determine which physiological and morphological characteristics are predominantly contributing to N efficiency, a hydroponic experiment was conducted. Two contrasting potato cultivars (Agria: N‑efficient and Van Gogh: N‑inefficient) were grafted reciprocally onto each other. Grafted and non-grafted control plants were grown in a growth chamber for 42 days in 8 L pots filled with continuously aerated nutrient solution under two N rates (Low-N : 0.5 mM N and High-N : 3.0 mM N) by using a deep water culture (DWC) technique. The shoot and root fresh (FW) and dry (DW) weights, main stem length, number of leaves, total leaf area, photosynthetic activity of leaves, shoot and root N concentration, total N uptake, total root length and root volume of potato plants were significantly increased with increased N rate. The grafted plants produced significantly higher above ground biomass than non-grafted ones, indicating that N efficiency was significantly improved by the reciprocally grafting under low and high N rates. Non-grafted cv. Agria showed higher numbers of shoot and root FW and DW, total leaf area, intensity of photosynthesis net measurements, compared to non-grafted cv. Van Gogh under both N rates. In reciprocal grafting, the growth performance of cv. Agria slightly increased when it was grafted onto cv. Van Gogh, whereas a significant increase in crop growth performance was recorded when cv. Van Gogh was grafted onto cv. Agria. The N efficiency of non-grafted cv. Agria was closely associated with its vigorous root growth and active root system under both N conditions. Same root morphological characteristic could not be exhibited by the N‑inefficient cv. Van Gogh. Our study suggested that root morphological characteristics are contributing more than shoot characteristics to N efficiency of potatoes. These traits could be useful characters to breed/select N‑efficient potato rootstocks for sustainable agriculture in the future.

Tomato growth, yield, and quality response to mixed chemical–organic fertilizers and grafting treatments in a high tunnel environment

Tomato (Solanum lycopersicum L.) is a major vegetable crop world-wide and grown in high tunnels in many regions. This study investigates the use of two fertilizer sources, chemical and integrated (composted poultry manure plus urea) fertilizers, and grafting on growth, nitrate-N content, yield, and fruit quality of tomato grown in high tunnels in northwestern Washington. Grafting treatments consisted of ‘Panzer’ tomato grafted on one of three tomato rootstocks ‘Estamino’, Maxifort’, ‘DRO138TX’, or non-grafted (control). Application of chemical fertilizer increased number of leaves per plant, plant height, and cumulative fresh biomass of pruned suckers relative to tomato plants grown with the integrated fertilizer treatment. Grafted tomato plants had greater plant growth than non-grafted plants throughout the growing season. There was no significant difference between fertilizer treatments on nitrate-N concentration in plant tissue or fresh petiole sap; however, grafted plants contained higher levels of nitrate-N than non-grafted plants. Total and marketable fruit weight and number did not differ due to fertilizer source, but total and marketable fruit weight was higher for grafted plants than for non-grafted plants in 2016. There was no significant effect due to fertilizer source on fruit firmness, water content, pH, titratable acidity, and β-carotene; however, total soluble solids (TSS) and lycopene content were higher for fruit grown with integrated fertilizer in 2016. Grafting enhanced water content of tomato fruit in 2015, and TSS (°Brix) in 2016.

ЭФФЕКТИВНОСТЬ ПРИМЕНЕНИЯ ОТЕЧЕСТВЕННЫХ ПОДВОЕВ ТЫКВЫ ДЛЯ ПРИВИВКИ ОГУРЦА В ЗАЩИЩЕННОМ ГРУНТЕ

When growing herbaceous vegetable crops in the world practice, great importance is given to the use of grafting method. The development of environmentally safe methods to increase the yield and resistance of plants to adverse growing conditions is very relevant in vegetable production. One such method in pumpkin crops is grafting. The aim of our work was to study the effect of domestic pumpkin rootstock on growth, development and yield characteristics of cucumber hybrid using grafting method. Grafting on pumpkin species improved the growth and development of plants depending on the rootstock, compared with rootstock plants. The aim of our research was to study the influence of domestic pumpkin rootstock on the growth, development and yield characteristics of the cucumber hybrid (scion). As a scion, the variety (Asylum), recommended for cultivation in protected ground conditions, was used, which was grafted on five domestic rootstocks: 1 (Mozoleevskaya 10), 2 (Karina), 3 (Aphrodite), 4 (Mindalnaya) and Russian selection 5 (Stofuntovaya) pumpkins from vegetable and melon crops. According to the generally accepted method, the graft was grafted (cucumber Asylum) on the rootstocks of pumpkin. Using a sample of pumpkin 1 (Mozoleevskaya 10), flowering began on the fifth day earlier in comparison with non-grafted plants, and when grafting on a sample of pumpkin 4 (Aphrodite), the fruit ripened earlier by six days. To get the greatest increase in early productivity by 30%, it is possible to use both rootstocks. A significant increase in total yield was provided by samples of rootstocks 2 (Karina) – 3.9 kg/m2 and 3 (Stofuntovaya) - 8.0 kg/m2. The grafted cucumber plants with all the rootstocks used were superior to the root ones in height, in terms of the percentage of marketability of fruits and in terms of fruit weight. At the beginning of fruiting on grafted cucumber plants, the number of female flowers increased depending on the sample. In all grafted plants, the dry matter content in the fruit increased significantly. Because of our research, rootstocks 2 (Karina) and 3 (Stofuntovaya) were noted, which are recommended for use in further research breeding work and the production of grafted plants.

Growth behaviour and fruit productivity of watermelon as an affected with grafting onto different rootstock genotypes

The experiments were conducted on watermelon (Citrullus lanatus L.) at an a private farm in Awlad Amr village, Qena city, Qena, Egypt located between 26° 10′ 0″ N, 32° 43′ 0″ E during the two consecutive spring-summer seasons of 2018 and 2019 respectively to study the effect of three different genotypes used as rootstocks on plant growth performance, fruit yield and quality of three watermelon F1 hybrids. Tongue approach grafting method was used, three hybrids of watermelon which growing on a large scale of the commercial production of watermelons in Egypt namely, Aswan F1, Misr1 F1 and Star F1 was grafted onto three different genotype rootstocks i.e. Cobalt F1, Ferro F1 and New Star F1. The experiment was laid out in Randomized Complete Block Design (RCBD) with three replications. Calculated data revealed that, there are clear significant differences between the grafted and non-grafted plants. Results of yield characteristics and its component, such as fruit weight, fruits length and circumferences and total fruit yield per feddan (ton) (feddan = 0.420 hectares = 1.037 acres), indicated to the superiority of the Misr 1 F1 hybrid which grafted onto Cobalt F1 rootstock, followed by the Aswan F1 when grafted onto Cobalt F1 rootstock. On the other side, Ferro F1 rootstock was poorly adapted with the all commercial hybrids of watermelon under studies.