Thompson Seedless Research Articles

Optimization of GA3 concentration for improved bunch and berry quality in grape cv. Crimson Seedless (Vitis vinifera L)

Crimson Seedless is a coloured seedless grape, gaining popularity in India for its attractive colour, bunch and berry quality with better shelf life. In cultivation of any seedless grape variety, application of GA3 at different stages is very much essential to produce good quality berries and bunches. However, this variety is highly sensitive to excess application of GA3 and practicing GA3 schedule similar to that of Thompson Seedless grapes adversely affects bunch quality. Hence, there was a need to standardize mild dose of GA3 just for rachis elongation which will help to reduce bunch compactness to a greater extent. Hence, an experiment was initiated to standardize concentration of GA3 for rachis elongation of Crimson Seedless grapes. Three different concentrations of GA3 {viz., 5 ppm (T1), 7.5 ppm (T2) and 10 ppm (T3)} were sprayed during pre bloom stage and compared with unsprayed control (T4). Among different treatments, pre-bloom spray of GA3@5 ppm could produce less compact bunches with highest average bunch weight, berry weight, berry length and TSS. However, bunches sprayed with 7.5 ppm and 10 ppm GA3 could also produce good quality bunches average berry weight and TSS was less. Because of severe coiling of rachis at 7.5 ppm and 10 ppm GA3 spraying, bunches were too straggly compared to spraying of 5 ppm GA3. The control bunches without GA3 spray produced very compact clusters with less average bunch weight, berry weight, berry diameter and berry length.

Screening of phenolic compounds in australian grown grapes and their potential antioxidant activities

Grapes (Vitis Vinifera) are one of the world's most utilised and prized fruit. Grapes are a great source of antioxidants due to the abundance of phenolic compounds. Grape pulp is the main part of the grape being consumed. The pulp of five Australian grown grapes – Dawn Seedless (DS), Calmeria (CG), Golden Globe (GG), Menindee Seedless (MS), and Thompson Seedless (TS) will be qualitatively and quantitatively analysed for its phenolic composition and antioxidant capacity. The general trend followed: GG > TS > MS > DS > CG, and the phenolic content of the pulp also presented a significant positive correlation with the antioxidant capacity. GG revealing the highest levels of TPC (4.31 ± 0.11 mg GAE/g) and TFC (0.48 ± 0.09 mg QE/g) while TS were highest in TTC (0.94 ± 0.12 mg CE/g). Similarly, GG exhibited higher antioxidant capacity in DPPH (5.84 ± 0.17 mg AAE/g), FRAP (4.91 ± 0.14 mg AAE/g), and TAC (6.78 ± 0.12 mg AAE/g), while TS revealed highest radical scavenging ability for ABTS (4.56 ± 0.19 mg AAE/g). The LC-ESI-QTOF-MS/MS tentatively identified 78 phenolic compounds consisting of flavonoids (36), phenolic acids (31), lignans (3), stilbenes (1), and other polyphenols (7) in five grapes samples. Ten most abundant fruit-based targeted polyphenols were quantified. GG had a higher phenolic concentration in HPLC-PDA quantification, particularly for phenolic acids (gallic acid and chlorogenic acid) and flavonoids (kaempferol). Our study provides relatively adequate information on grape pulp's phenolic content and antioxidant capacity, providing confidence and research prospects to promote grape pulp use in different food, pharmaceutical and supplement industries, and even influencing grape cultivation.

VvEIL2 and VvEIL4 regulate ethylene synthesis and carotenoid metabolism during senescence of grape rachis

To understand the mechanisms underlying rachis browning and how to delay post-harvest rachis senescence, ‘Shine Muscat’ grape clusters were treated by 1-methylcyclopropene before cold storage. Rachis browning index, ethylene production, and carotenoid content were determined, and the transcriptome of rachis and the regulation of VvEIL2 and VvEIL4 were explored. The results indicated that 1-MCP treatment inhibited rachis browning, and ethylene production and carotenoid content were decreased in the rachis compared to the control in the 2nd week of storage. Transcriptome analysis showed that carotenoid synthesis and lysine degradation pathways were the most enriched during rachis senescence. Transient over-expression of VvEIL4 in ‘Thompson Seedless’ grape leaves induced VvACS5, VvACO2, and VvERF95 expression and ethylene production. Both VvEIL4 and VvERF95 could activate VvACS5 and VvACO2 promoters. Transient over-expression of VvEIL2 in grape leaves decreased the transcript levels of key genes in carotenoid metabolism. Dual-luciferase assays further verified the activation of the VvCrtISO promoter by VvEIL2 was inhibited. These results suggested that VvEIL2 and VvEIL4 regulate ethylene synthesis and carotenoid metabolism during the senescence of grape rachis.

Occurrence of Grapevine Leafroll-Associated Virus-3 (GLRaV-3), Complete Nucleotide Sequence and Cultivar Susceptibility to a GLRaV-3 Isolate from Shaanxi Province of China

Grapevine (Vitis spp.) is globally one of the most economically important fruit crops. China is the largest grapevine-growing country of the world and Shaanxi province is one of the major grapevine-growing provinces in the country. A survey of GLRaV-3 found it widespread, with 57–100% infection frequencies, in both wine and table grapevine cultivars of three grapevine-growing regions of Shaanxi province. The virus infection frequencies varied with cultivars and regions. In order to obtain the full genomic length of a new GLRaV-3 isolate, GLRaV-3-Sau (accession number MK988555), was sequenced. This isolate has a genome of 18026 nucleotides, and 14 open reading frames (ORFs). The full-genome of the isolate GLRaV-3-Sau shared 85.88% nucleotide identity to GLRaV-3-LN, another isolate found in China. Coat protein (CP) genes of GLRaV-3 isolates were identical (99%) to the Vitis vinifera isolate (accession number HQ185608.1) from the USA. Immunohistochemistry for virus localization found that distribution patterns were similar in red-berried cultivar ‘Cabernet Sauvignon’ and white-berried cultivar ‘Chardonnay’, and GLRaV-3 is restricted in phloem tissue of vascular bundles. Virus transmission by micrografting found virus transmission efficiency was higher in ‘Chardonnay’ and ‘Thompson Seedless’ than in ‘Hunan-1’, indicating that ‘Hunan-1’ was less sensitive to GLRaV-3. As far as we know, these are the most comprehensive comparisons on the genome and CP genes of GLRaV-3 worldwide and the first to have found that the grapevine ‘Hunan-1’ is less susceptible to GLRaV-3.

Near-harvest application of methyl jasmonate affected phenolic content and antioxidant properties in "Thompson Seedless" grape.

The influence of methyl jasmonate (MJ) preharvest treatment was investigated on some polyphenols and antioxidant systems in the “Thompson Seedless” table grape. The clusters were sprayed in the vineyard 2 days before harvest with 0, 1, 5, and 10 mM MJ. After picking, berries were stored for 6 days at 15°C, simulating marketing conditions. Total phenols and flavonoids were affected by MJ treatment, especially at 10 mM concentration, whereas total tannins were found to be unchanged. Antioxidant activity of the treated skin was noticeably higher compared with the control, together with PAL and POD activity. Although MJ had little effect on catechin and epicatechin, the levels of quercetin and rutin were noticeable. In addition, 5 and 10 mM MJ exerted a pronounced effect on transresveratrol content. These data showed that a single preharvest application close to the harvest time could be an effective treatment to promote the antioxidant properties of the grape.

Evaluation of yield attributes of wine varieties of grape under Telangana Conditions

Thirteen wine grape varieties of which eight coloured and five white were evaluated for flowering, bunch characters and yield attributes under Telangana conditions at Grape Research Station, Hyderabad. Observations recorded on flowering, bunch characters and yield attributes revelead that days taken for 50% flowering varied significantly from minimum of 25.36 days in the variety Pusa Navrang to maximum of 44.37 days in Thompson Seedless. The variety Chenin Blanc recorded highest number of bunches per vine (113.78) followed by Shiraz (97.75) and least in the variety Thompson Seedless (37.26) where as maximum bunch weight was noticed in the variety Italia (331.61 g) followed by Thompson Seedless and minimum in Cabernet Sauvignon (88.06 g). Yield ranged from 4.51 to 16.81 kg/vine with maximum recorded by the variety Chenin Blanc (16.81 kg/vine) while it was minimum with Sauvignon Blanc (4.51 kg/vine). Heat unit requirement in different cultivars of grape varied from 1726.25 degree days to 2207.46 degree days being recorded maximum by the variety Italia and minimum by Pusa Navrang. These results signify the potential ‘for cultivation of wine grape varieties under Southern Zone of Telangana.

Effects of dehydration speed on the metabolism of membrane lipids and its relation to the browning of the Thompson seedless grape

AbstractXinjiang is the main producing area of raisins and the largest green raisins production base in China. The browning of Thompson seedless grape raisin is extremely serious during the drying process, and has become the key issue in the development of Xinjiang raisin industry. Previous studies have shown that dehydration speed has a great impact on the browning of Thompson seedless grape, but few relevant mechanisms have been studied. Here, we demonstrate the effect of dehydration speed on lipid metabolism and its relation to the browning of the Thompson seedless grape during drying. Compared to slow dehydration treatment, rapid dehydration treatment of the Thompson seedless grape exhibited a lower degree of browning and activities of lipoxygenase (LOX), a higher index of unsaturated fatty acids and degree of unsaturated fatty acid. Moreover, the Thompson seedless grape treated with rapid dehydration resulted in a lower rate of superoxide anion production, hydrogen peroxide content, membrane permeability, and malondialdehyde content. These findings demonstrate that rapid dehydration inhibiting the browning of Thompson seedless grapes might be due to the inhibiting activities of LOX and the lower accumulation of reactive oxygen species. These activities can inhibit lipid peroxidation and slow the decomposition of unsaturated fatty acid in the membrane in Thompson seedless grapes, protecting the cellular membrane structural integrity, which may result in less contact of polyphenol oxidase with phenolic substrates and less enzymatic browning during drying. The results provide a theoretical basis for the application of rapid dehydration in drying Thompson seedless grapes.

Modeling and Optimizing the Effects of Trichoderma on Quality, Decay Extension Rate and Phytochemical Compounds of Thompson Seedless Table Grapes by the Use of Response Surface Methodology

Modeling and Optimizing the Effects of Trichoderma on Quality, Decay Extension Rate and Phytochemical Compounds of Thompson Seedless Table Grapes by the Use of Response Surface Methodology

CRISPR/Cas9 Targeted Editing of Genes Associated With Fungal Susceptibility in Vitis vinifera L. cv. Thompson Seedless Using Geminivirus-Derived Replicons.

The woody nature of grapevine (Vitis vinifera L.) has hindered the development of efficient gene editing strategies to improve this species. The lack of highly efficient gene transfer techniques, which, furthermore, are applied in multicellular explants such as somatic embryos, are additional technical handicaps to gene editing in the vine. The inclusion of geminivirus-based replicons in regular T-DNA vectors can enhance the expression of clustered regularly interspaced short palindromic repeats/CRISPR-associated protein 9 (CRISPR/Cas9) elements, thus enabling the use of these multicellular explants as starting materials. In this study, we used Bean yellow dwarf virus (BeYDV)-derived replicon vectors to express the key components of CRISPR/Cas9 system in vivo and evaluate their editing capability in individuals derived from Agrobacterium-mediated gene transfer experiments of ‘Thompson Seedless’ somatic embryos. Preliminary assays using a BeYDV-derived vector for green fluorescent protein reporter gene expression demonstrated marker visualization in embryos for up to 33 days post-infiltration. A universal BeYDV-based vector (pGMV-U) was assembled to produce all CRISPR/Cas9 components with up to four independent guide RNA (gRNA) expression cassettes. With a focus on fungal tolerance, we used gRNA pairs to address considerably large deletions of putative grape susceptibility genes, including AUXIN INDUCED IN ROOT CULTURE 12 (VviAIR12), SUGARS WILL EVENTUALLY BE EXPORTED TRANSPORTER 4 (VviSWEET4), LESION INITIATION 2 (VviLIN2), and DIMERIZATION PARTNER-E2F-LIKE 1 (VviDEL1). The editing functionality of gRNA pairs in pGMV-U was evaluated by grapevine leaf agroinfiltration assays, thus enabling longer-term embryo transformations. These experiments allowed for the establishment of greenhouse individuals exhibiting a double-cut edited status for all targeted genes under different allele-editing conditions. After approximately 18 months, the edited grapevine plants were preliminary evaluated regarding its resistance to Erysiphe necator and Botrytis cinerea. Assays have shown that a transgene-free VviDEL1 double-cut edited line exhibits over 90% reduction in symptoms triggered by powdery mildew infection. These results point to the use of geminivirus-based replicons for gene editing in grapevine and other relevant fruit species.

Cloning and activity analysis of the highly expressed gene VviABCG20 promoter in seed and its activity is negatively regulated by the transcription factor VviDof14

Half-size ATP binding cassette G (ABCG) transporters participate in the growth and development of plants by transporting substrates. The VviABCG20 gene is highly expressed in seed and plays an important role in seed development/abortion. However, little is known about the function of the VviABCG20 promoter (pVviABCG20) and its regulatory factors. In our study, we obtained pVviABCG20s from 15 seeded and seedless grape varieties and there were two types of ‘a’ and ‘b’ with 41 bp non-deletion or deletion, respectively. The pVviABCG20 activity was higher in seeds, siliques, flowers and roots of pVviABCG20-GUS Arabidopsis. The GUS activity analysis revealed that the activities of P4 (-586 bp) to P7 (-155 bp) were becoming increasingly weaker, and the P7 activity almost disappears compared with the pVviABCG20 (P0, -1604). Yeast one-hybrid and GUS activity analysis indicated that VviDof14 binds to the AAAG element in the P7′ (-586 bp) fragment of the pVviABCG20 and regulated the activity negatively. The quantitative real-time PCR analysis suggested that the expression of VviDof14 in Thompson seedless seeds was higher than that in Pinot noir. Our study laid the foundation for further analysis of the functions of the pVviABCG20 and its regulator VviDof14 in grape seed development/abortion.

Pre-Anthesis Cytokinin Applications Increase Table Grape Berry Firmness by Modulating Cell Wall Polysaccharides.

The use of plant growth regulators (PGRs) is widespread in commercial table grape vineyards. The synthetic cytokinin CPPU is a PGR that is extensively used to obtain higher quality grapes. However, the effect of CPPU on berry firmness is not clear. The current study investigated the effects of pre-anthesis applications (BBCH15 and BBCH55 stages) of CPPU on ‘Thompson Seedless’ berry firmness at harvest through a combination of cytological, morphological, and biochemical analyses. Ovaries in CPPU-treated plants presented morphological changes related to cell division and cell wall modification at the anthesis stage (BBCH65). Moreover, immunofluorescence analysis with monoclonal antibodies 2F4 and LM15 against pectin and xyloglucan demonstrated that CPPU treatment resulted in cell wall modifications at anthesis. These early changes have major repercussions regarding the hemicellulose and pectin cell wall composition of mature fruits, and are associated with increased calcium content and a higher berry firmness at harvest.

Response of Thompson Seedless grapevines to foliar sprays with GA3 and some natural compounds

Response of Thompson Seedless grapevines to foliar sprays with GA3 and some natural compounds

Effect of Chlormequat Chloride on Vegetative Growth, Photosynthetic Activities, and its Residual Dissipation in Thompson Seedless Grapevines

Chlormequat chloride is one of the important plant growth regulators which is a highly stable gibberellins biosynthesis inhibitor used to inhibit vegetative growth and cell elongation. Considering the importance of plant growth inhibitors, the present investigation was carried out to understand the effect of Chlormequat chloride with its different concentrations on vegetative growth, photosynthetic activities and its residual dissipation in Grapevines at two different locations one at Pune, Maharashtra India and second at Nashik, Maharashtra, India during the year 2018-2019. Chlormequat chloride was applied as a foliar spray, where the whole vines were sprayed at concentration of 500, 1000, 1500, 2000 and 2500 ppm with untreated control as a water spray; as a treatments with different developmental stages Viz 5th, 7th, and 15th leaf stage after foundation pruning. Morphological observations were recorded at 45 days and 90 days after foundation as well as fruit pruning. Application of Chlormequat chloride recorded reduced shoot length and Internodal distance while increased in cane diameters, leaf thickness after both the pruning’s in this investigation Photosynthetic activity, yield per vines and percent fruitfulness had significantly influenced with the application of Chlormequat chloride in grapevines. The dissipation of Chlormequat chloride was stable and indicated a non- linear pattern of degradation. Thus, implied that simple first-order kinetics might not be adequate to explain the dissipation behaviour of Chlormequat chloride in grapes.

Performance of 'Thompson Seedless' Table Grape Cultivar during Shelf Life in Terms of Quality Grafting on Different Rootstocks

Performance of 'Thompson Seedless' Table Grape Cultivar during Shelf Life in Terms of Quality Grafting on Different Rootstocks

Silica Nanoparticles as a Probable Anti-Oomycete Compound Against Downy Mildew, and Yield and Quality Enhancer in Grapevines: Field Evaluation, Molecular, Physiological, Ultrastructural, and Toxicity Investigations.

Downy mildew is the most destructive disease of grapevines in the regions of relatively warm and humid climate causing up to 50% yield losses. Application of silicon- (Si-) based products have been extensively studied against various oomycete, fungal, bacterial, and viral plant diseases, but studies on Si application in their nanosize are limited. In this study, the field application of silica nanoparticles (SiNPs) on Thompson Seedless grapevines (H4 strain) infected with downy mildew was evaluated. In addition, molecular, physiological, ultrastructural, and toxicity investigations were also conducted. The obtained results revealed that spraying of grapevines with SiNPs at 150 ppm significantly overexpressed the transcription factor jasmonate and ethylene-responsive factor 3 recording 8.7-fold, and the defense-related genes β-1,3-glucanase (11-fold), peroxidase (10.7-fold) pathogenesis-related-protein 1 (10.6-fold), and chitinase (6.5-fold). Moreover, a reduction up to 81.5% in the disease severity was achieved in response to this treatment. Shoot length and yield per grapevine were considerably enhanced recording up to 26.3 and 23.7% increase, respectively. The berries quality was also improved. Furthermore, this treatment led to an enhancement in the photosynthetic pigments, induction of phenolic and ascorbic acid contents, an increase in the activity of peroxidase and polyphenol oxidase enzymes, and a reduction in the cellular electrolyte leakage, lipid peroxidation, and H2O2 content. Scanning electron microscopy observations showed an increase up to 86.6% in the number of closed stomata and a reduction up to 55% in the average stomatal pore area in response to this treatment. Observations of the transmission electron microscopy showed ultrastructural alterations in the cells of a grapevine leaf due to the infection with downy mildew, including plasmolysis and disruption of the cellular components, abnormal chloroplasts, and thickening of the cell wall and cell membrane. These abnormal alterations were reduced in response to SiNPs spray. In contrast, this study also showed that this treatment had considerable cytotoxic and genotoxic effects at this direct dose/concentration. So, additional investigations to determine the SiNPs residue in the produced edible plant parts are urgently needed. In addition, the pre-harvest interval, toxicity index, and risk assessment should be evaluated before any recommendation for use.

Novel Clotrimazole and Vitis vinifera loaded chitosan nanoparticles: Antifungal and wound healing efficiencies

Chitosan integrated nanoparticles of clotrimazole and Egyptian Vitis vinifera juice extract was evaluated in order to maximize the antifungal activity and reduce the gross side effects. In the present study Egyptian Thompson Seedless Vitis vinifera and Clotrimazole (Cz) loaded chitosan nanoparticles (NCs/VJ/Cz) showed a promising antifungal effect with average inhibition zone diameters of 74 and 72 mm against Candida albicans and Aspergillus niger respectively. NCs/VJ /Cz was stable with significant drug entrapment efficiency reached 94.7%; PDI 0.24; zeta potential value + 31 and average size 35.4 nm diameter. Ex vivo and in vivo evaluation of skin retention, permeation and wound repair potentialities of NCs/VJ /Cz ointment was examined by experimental rats with wounded skin fungal infection. Data proved the ability of NCs/VJ /Cz to gradually release the drugs in a sustained manner with complete wound healing effect and tissue repair after 7 days administration. As a conclusion NCs/VJ /Cz ointment can be used as a novel anti-dermatophytic agent with high wound healing capacity.

Rachis browning and water loss description during postharvest storage of ‘Krissy’ and ‘Thompson Seedless’ table grapes

Rachis browning is a serious symptom of water loss affecting the quality of table grapes (Vitis vinifera L.) during storage. It has been evaluated subjectively based on a color scale or by image analysis, while water loss, which is considered as the main factor behind this problem, is mostly measured on basis of whole-cluster weight loss, with only few studies focusing on the rachis exclusively. Our main objective was to compare the sensitivity to water loss and rachis browning of ‘Krissy’ and ‘Thompson Seedless’ cultivars under different storage conditions and using different methods of evaluation (NIR spectrometry, image analysis, colorimeter, weight loss from initial weight and relative water content). The rachises were evaluated during 3 d subjected to a combination of temperatures (0 °C or 20 °C), relative humidity (Saturated or reduced RH), and previous storage at 0 °C for 0 (HT, Harvest Time) and 30 days (ST, Storage Time). NIR spectra (896−2500 nm) were collected, and Partial Least Squares regression (PLS) models were calculated to test the correlation between the spectra and the measurements from other evaluation techniques. Results showed that ‘Krissy’ is more sensitive to dehydration symptoms than ‘Thompson Seedless’. Saturated RH combined with low temperature (0 °C) are the most suitable to reduce rachis browning and water loss during the 3 d of storage at both HT and ST. The decrease in RWC (Relative Water Content) coincided with an increase in rachis browning throughout storage. Additionally, results provided six NIRS-based prediction models for browning severity (R2 = 0.82 and 0.84), hue color (R2 = 0.68 and 0.72) and water loss (R2 = 0.63 and 0.90) in rachises of ‘Krissy’ and ‘Thompson Seedless’, respectively. These results demonstrate that the NIRS can be a suitable non-destructive method to quantify a range of rachis browning severity produced under different storage conditions.

Fresh grapevine (Vitis vinifera L.) leaves: Postharvest biology and handling recommendations

Developing grapevine leaves are harvested for the preparation of stuffed dolmas. Fresh leaves are preferred, but since they are perishable and can be harvested at ideal maturity for only a limited period, most leaves for dolmas are currently preserved. This research on fresh grapevine leaves (var. Thompson Seedless) was conducted over three seasons, and focused on their postharvest performance in relation to leaf maturity, respiration rates, storage temperature, water loss and packaging, and decay control. Appropriate leaf maturity for dolmas are leaves that are bright green and not yet fully expanded. The 4 leaf maturity stages that can be harvested commercially for dolmas are clearly delineated by differences in color, and corresponding color values and pigment concentrations. Sugar, acid, and phenolic concentrations and % dry weight vary little among the 4 maturity stages studied. Respiration rates of grapevine leaves (mature for dolmas) are moderate, about 350 µmol CO2 kg−1h − 1 at 5 °C. Grapevine leaves can be stored for 4–8 weeks at 0 °C. A storage period of 1 month can be expected if they are stored in the range of 0–5 °C. Grapevine leaves can be stored below 0 °C but freezing injury occurs near -2.5 °C. Water loss at 8–10% is needed to reduce marketable quality (loss of gloss, leaf curling, browning). Botrytis decay is the major limitation to storage life and decay incidence varied from harvest to harvest. Decay is partially retarded by high CO2 atmospheres (10–15% v/v), but is more effectively controlled by hot water dips of 47.5 °C to 52 °C (15 to 9 min). Grapevine leaves harvested for dolmas do not show yellowing during aging or senescence when held below 10 °C.

Development and performance evaluation of grape debunching machine for production of raisins and stemless table grapes

AbstractChemical pretreatment before drying is a practice in raisin making which has many limitations and use of chemical shall be discouraged. A new process is being developed with physical pretreatment. The process requires intact grape berries for further processing. Therefore, a grape debunching machine has been developed for separation of intact berries from the bunch. The machine consists of central rotor with helical fingers. The rotor assembly is surrounded by perforated trough through which the detached berries drop. The performance of the machine was evaluated with “Thompson Seedless” table grape for debunching efficiency and damage to berries. The rotor speed (80–120 rpm) and concave clearance (5–25 mm) were selected as independent parameters. The debunching efficiency and percentage of damaged berry were in the range of 77.17–98.73% and 5.75–11.82%, respectively. The maximum debunching efficiency (94.33%) and minimum berry damage (7.10%) was obtained at rotor speed of 100 rpm and concave clearance of 15 mm. The capacity of grape debunching machine was found to be 145.2–150.2 kg/hr for different grape varieties, namely Thompson Seedless, Manik Chaman, and Fantasy Seedless. The developed machine will be useful in production of raisins without use of chemicals and stemless table grapes.Practical applicationsThe conventional process of raisin making involves intensive use of chemicals right from dipping of harvested grape bunch in a solution of ethyl oleate (1.5%) and potassium carbonate (2.5%), intermittent sprays, and further use of booster and sulfur dioxide for color improvement. The intensive use of chemicals triggers the food safety issues. Furthermore, the process requires longer drying time, involves more number of unit operations, and fetches losses of grapes. To address these issues, an alternative chemical‐free process has been developed by the authors of this investigation for the production of raisins. This process requires the grape berries to be individualized before further processing which is tedious and time consuming if done manually. Therefore a grape de‐bunching machine has been developed for separation of intact grape berries which can be further processed into raisins at industrial scale without use of chemicals. The developed machines will find applications in the minimally processed/individual quick freezing (IQF) of table grapes for which there is an increasing market especially in super market.

Elevated carbon dioxide and temperature effects on rooting behaviour of grape cuttings

An experiment was laid out to study the impact of eCO2 (550ppm), eT (+3ºC) and their interaction (eCO2+eT) on rooting behaviour of cuttings of three grape varieties- Thompson Seedless, Bangalore Blue, and Dogridge in FATE and OTC facilities. Observations were recorded at 50 and 80 days after planting (DAP) and root growth data was recorded and analysed using WinRHIZO root scanner and its software. Analysis revealed that, among the selected grape varieties, Thompson Seedless cuttings has shown highest number of roots, root volume and dry biomass under eCO2 and eCO2+ eT conditions, while total root length and root length density were highest with Bangalore Blue. Under eT condition, Bangalore Blue showed highest number of roots, total root length and root length density, while root volume and dry biomass was highest with Thompson Seedless. The per se values of root parameters under all conditions and their response to eCO2 was lowest with Dogridge. Though eT condition reduced all the root parameters, their performance improved under eCO2+ eT indicating the presence of higher concentration of CO2 reduced the ill effects of high temperature. Overall, eCO2 and eCO2+eT conditions improved root parameters of grape varieties, while eT reduced them as compared to their performance under ambient condition and varietal variation is significant.