Berry Color Research Articles

Metabolomic and transcriptomic analyses reveal the effects of self- and hetero-grafting on anthocyanin biosynthesis in grapevine.

Grafting, which joins a scion from a cultivar with the stem of a rootstock from a grapevine wild relative, is commonly used in viticulture. Grafting has crucial effects on various phenotypes of the cultivar, including its phenology, biotic and abiotic resistance, berry metabolome, and coloration, but the underlying genetics and regulatory mechanisms are largely unexplored. In this study, we investigated the phenotypic, metabolomic, and transcriptomic profiles at three developmental stages (45, 75, and 105 days after flowering) of the Crimson Seedless cultivar (Vitis vinifera) grafted onto four rootstocks (three heterografts, CS/101-14, CS/SO4, and CS/110R and one self-graft, CS/CS) with own-rooted graft-free Crimson Seedless (CS) as the control. All the heterografts had a significant effect on berry reddening as early as ~45 days after flowering. The grafting of rootstocks promoted anthocyanin biosynthesis and accumulation in grape berries. The metabolomic features showed that cyanidin 3-O-glucoside, delphinidin 3-O-glucoside, malvidin 3-O-glucoside, peonidin 3-O-glucoside, and petunidin 3-O-glucoside were the pigments responsible for the purplish-red peel color. Transcriptomic analyses revealed that anthocyanin biosynthesis-related genes, from upstream (phenylalanine ammonia-lyase) to downstream (anthocyanidin 3-O-glucosyltransferase and anthocyanidin synthase), were upregulated with the accumulation of anthocyanins in the heterografted plants. At the same time, all these genes were also highly expressed and more anthocyanin was accumulated in self-grafted CS/CS samples compared with own-rooted graft-free CS samples, suggesting that self-grafting may also have promoted berry reddening in grapevine. Our results reveal global transcriptomic and metabolomic features in berry color regulation under different grafting conditions that may be useful for improving berry quality in viticulture.

MITIGATION OF EXCESSIVE PROTON CONCENTRATIONS OF “CRIMSON” GRAPES BY THIDIAZURON AND BENZYLADENINE

The present study was conducted during the two consecutive seasons 2018 and 2019 on "Crimson Seedless" table grapes to mitigate the excessive ProTon concentration by some cytokinin use. The following treatments were used: control, thidiazuron at 50ppm (TDZ), abscisic acid at 250ppm (ABA) preceded by TDZ at 50ppm, ABA at 500ppm preceded by TDZ at 50ppm, benzyl adenine at 50ppm (6-BA), ABA at 250ppm preceded by 6-BA at 50ppm, ABA at 500ppm preceded by 6-BA at 50ppm, ABA at 250ppm and ABA at 500ppm.Treatment of TDZ and 6-BA were applied at berry set while ABA treatment was applied at 10-15% berry coloration. The results showed that pre-harvest application of TDZ or 6-BA increased cluster weight, 100 berry weight, pedicel weight, berry acidity, berry and leaves chlorophylls and decreased berry coloration, TSS, total sugars. The application of ABA at 10-15% berry coloration enhanced berry anthocyanin content, TSS, Total sugars and lowered acidity and chlorophyll. The present study recommended using either TDZ or 6-BA at 50ppm followed by ProTon at 500ppm to mitigate the excessive ProTon concentration on "Crimson Seedless" grapes.

Horoz Karası üzüm çeşidinde bazı kalite parametrelerinin belirlenmesi

In this study, some quality elements of the Horoz Karası grape variety were investigated. For this purpose, cluster, berry, total soluble solids (TSS), titration acidity, pH level, berry color, total phenol, and antioxidant activity were determined in sample clusters of the Horoz Karası grape variety taken from the producer vineyards in Kahramanmaraş. In the Horoz Karası grape cultivar, total soluble solids (TSS) level was recorded between 16.6-25.35%, titratable acidity between 0.189-0.517, pH level 3.62 and 3.94. In Horoz Karası grape samples, L*, which expresses brightness, was determined between 25.64 and 29.97, a* value between 0.32-1.33, b* value between -0.91 and -0.23. Chroma value was recorded between 0.43-1.85 and CIRG (Color Index of Red Grapes) values were between 7.02 and 8.25. Hue angle was recorded between -40.88 - (-33.31) values in CIE (Commission Internationale de L'éclairage) color coordinate. According to the Hue angle values, the color of the berry of the Horoz Karası variety was recorded as purple.

Influence of abscisic acid,Ascophyllum nodosumandAloe veraon the phenolic composition and color of grape berry and wine of 'Cabernet Sauvignon' variety

In viticulture, various techniques can be used to improve productivity, tolerance to biotic or abiotic stress, the quality of grapes and wines such as the use of plant regulators and biostimulants. Thus, the objective of this work was to evaluate the effect of application of abscisic acid (S-ABA),Ascophyllum nodosum (A. nodosum)seaweed extract andAloe vera (A. vera)gel on phenolic composition and chromatic characteristics of grapes from the 'Cabernet Sauvignon' variety. The experiment was conducted in a commercial vineyard in Campo Largo - Paraná, in two consecutive seasons, 2017/18 and 2018/19, involving the following treatments: 1) control; 2) (S-ABA) 400 mg/L; 3) S- ABA 600 mg/L; 4)A. veragel 200 mL/L; 5)A. veragel 400 mL/L; 6) seaweed extract 0.2 mL/L; 7) seaweed extract 0.4 mL/L. Two applications were performed with the seaweed extract andA.gel when the bunches were atveraisonstage (50 and 75% of grape berries with coloration). Total anthocyanins content, total polyphenols content and activity of phenylalanine ammonia-lyase (PAL), polyphenoloxidase and peroxidase enzymes were assessed in the berries skin. Total anthocyanins, individual anthocyanins and total polyphenol contents as well as lightness, chroma and hue angle were analyzed in the corresponding wines. S-ABA increased the content of anthocyanins and total polyphenols, as well as the activity of PAL in the first season.A. nodosum(AN) seaweed extract increased the total polyphenol content, total anthocyanins content and PAL in the berry skin of 'Cabernet Sauvignon' variety. S-ABA increased the total polyphenol content and anthocyanins in wine, as well as theA. nodosum, in at least one of the evaluated seasons.

Determining a Midday Stem Water Potential Threshold for Irrigation of Table Grapes Water potential threshold

Sustainable table grape production depends on efficient water supply. Water potential is a useful indicator of water constraints in grapevines. In this regard, midday stem water potential (ΨS) is considered to be a better indicator of grapevine water status than leaf water potential (ΨL). The objective of the study was to determine a water potential threshold to set soil water refill lines for table grape irrigation. However, in previous studies carried out locally, only ΨL was measured. The relationship between ΨS and ΨL was determined for ten selected table grape cultivars. Since there were no differences between cultivars, a single equation could be used to convert midday ΨL measured in previous studies with table grapes to ΨS. Vegetative growth, berry mass and colour, as well as juice total soluble solids (TSS) data were pooled, and related to midday ΨS. This showed that -0.8 MPa seems to be a ΨS threshold for water constraints in the pre-harvest period that will allow sustainable growth and berry size for anisohydric table grape cultivars. The optimum ΨS for berry colour is between -0.8 MPa and -1.0 MPa. Consequently, a midday ΨS threshold of -0.8 MPa can be used to set refill points for irrigation where soil water content is measured on a regular basis in table grape vineyards.

Hydrogen Sulfide, Regulated by Vvwrky30, Promotes Berry Color Changes in Grapevine Cabernet Sauvignon

Hydrogen Sulfide, Regulated by Vvwrky30, Promotes Berry Color Changes in Grapevine Cabernet Sauvignon

РЕЗУЛЬТАТЫ ИЗУЧЕНИЯ ЭЛЕМЕНТНОГО СОСТАВА И КАЧЕСТВА ВИНОМАТЕРИАЛОВ ИЗ УСТОЙЧИВЫХ СОРТОВ ВИНОГРАДА НОВОГО ПОКОЛЕНИЯ

In recent years, much attention has been paid to the restoration and development of viticulture and winemaking in our country. The state promotes the planting of new vineyards by providing subsidies for for the establishment of vineyards and the care of young plantings. Favorable conditions are created for the competitiveness of domestic winegrowing products. Another vector of agricultural development is the growing popularity of organic farming products farming in the world. The Federal Law No 280-FZ “On Organic Products and on Amendments to Certain Legislative Acts of the Russian Federation” was adopted and entered into force on January 01, 2020. The principles of organic production are increasingly spread in viticulture production. Consequently the cultivation of resistant grape varieties is of great importance, because classic European varieties require repeated pesticide treatments to protect crops and plants from diseases. The purpose of the research is to assess qualitative composition of wine materials of a group of new resistant grape varieties for the production of red wines. The research involved the following resistant wine grape varieties by VCR breeding with red berry color: Merlot Early, Merlot Khorus, Cabernet Volos, Cabernet Eidos. Merlot variety served as the control. The origin of varieties is complex interspecific. The evaluation of the varieties of a new generation was carried out according to the methods generally accepted in viticulture and winemaking. When assessing the elemental composition of wine materials, quantitative parameters of the presence of 27 mineral elements in leaves and wine materials were established. It was found that potassium (1329.0–1877.0 mg/l) is in the first place in terms of content in wine materials, followed by sulfur, calcium, magnesium, silicon, phosphorus, sodium, boron, iron, copper, manganese, zinc. A significant excess of the content in the leaves and wine materials of the control variety compared with the experimental varieties was established by the content of iron, sodium, sulfur, phosphorus. The silicon content was higher in the experimental wine materials.

Inheritance of berry color in the progeny of red berry grape varieties

Inheritance of berry color in the progeny of red berry grape varieties

Effects of exogenous methyl jasmonate and light condition on grape berry coloration and endogenous abscisic acid content.

Suitable postharvest treatment methods were investigated to improve the color of grape berries. Culture solutions containing jasmonic acid (JA), methyl jasmonate (MeJA), and prohydrojasmon (PDJ) enhanced the skin coloration of grape berries (‘Pione’) harvested at the initial stage of coloration. MeJA vapor treatment under sealed conditions increased anthocyanin accumulation in grape berries (‘AkiQueen’ and ‘Pione’) harvested at the early stage of skin coloration. Furthermore, promoting skin coloration by MeJA vapor treatment was as effective in mature clusters as it was in detached berries. These effects were confirmed in light conditions but not in constant darkness. Our results showed that postharvest MeJA vapor treatment improved skin coloration in grapes. In addition, postharvest treatment with MeJA was found to have no effect on the endogenous abscisic acid content of grape berry skins. Therefore, we suggest that MeJA vapor treatment can be a useful and labor-saving method for the horticultural industry.

Some Important Food Quality Traits of Autochthonous Grape Cultivars

Grapes (Vitis L.), one of the most important and old fruit crops in the world, are grown in a wide range of environments from Australia to North America and from Japan to Chile. All grape growing countries use both international and local cultivars in production to obtain fresh and dried fruits or wine. In Turkey, each region has their own local grape cultivars. Seven local cultivars and one standard grape cultivar, grown in Coruh valley, were analyzed for morphological traits (bunch size, berry color, and berry shape), biochemical characteristics (sugars, organic acids, vitamin C, phenolic compounds, total carotenoids, and flavonoids content), and % inhibition level (antioxidant capacity). The grape cultivars differed from each other in the morphological and biochemical traits. The grape berries contain predominantly nine main phenolic compounds, five organic acids, and two sugars. Among phenolic compounds, chlorogenic acid, syringic acid, rutin, and quercetin were found to be dominant for most of the cultivars between 2.365–5.112 mg/L, 0.923–2.147 mg/L, 0.856–1.711 mg/L, and 0.621–1.347 mg/L, respectively. The local cultivar Kirmizi Istanbul had more chlorogenic acid than the other cultivars. The berries with darker skin color, specifically Kara Turfanda and Nanebur, had higher % inhibition level (antioxidant capacity) than the brighter ones, which correspond also to the results of flavonoid contents. Overall, the local genotypes were found promising due to favorable properties and could be recommended for farmers and consumers.

On the Biochemical and Physiological Responses of ‘Crimson Seedless’ Grapes Coated with an Edible Composite of Pectin, Polyphenylene Alcohol, and Salicylic Acid

The ‘Crimson seedless’ grape encountered several difficulties during shelf life, including weight loss, rachis browning, and berry shattering. The effect of exogenous pectin (PE) and polyphenol alcohol (PVA) with supporting salicylic acid (SA) at different concentrations (0, 1, and 2 mM) was applied. The coating was applied to bunches for 5 min and stored at room temperature (26 ± 1 °C and RH 65 ± 3%) for 4 days. In this study, postharvest application of PE + PVA-SA can significantly reduce the cell wall degradation enzyme activities of ‘Crimson seedless’ grape during shelf life. ‘Crimson seedless’ bunches, treated with PE + PVA-SA 2 mmol L−1, had a lowered rachis browning index (RB index), weight loss (WL%), and berry shattering percentage (BS%) and preserved berry color hue angle (ho) compared to untreated bunches during shelf-life duration. Moreover, the PE + PVA-SA 2 mM improved berry firmness (BF) and removal force (BRF). It also improved the soluble solid content (SSC%), titratable acidity (TA%), and SSC: TA-ratio, for assessing berry maturity. The cellular metabolism enzyme activities (CMEAs) of the cell wall such as polygalacturonase (PG), cellulase (CEL), xylanase (XYL), and pectinase (PT) were minimized by applying PE + PVA-SA 2 mM coatings throughout storage duration. The accumulation of malondialdehyde (MDA) and cell wall damage, as well as the electrolyte leakage percentage (EL%), was reduced. PE + PVA-SA 2 mM maintained DPPH radical quenching activities and minimized O2− and H2O2 production rates. Collectively, these findings suggest that PE + PVA with the presence of SA as a coating treatment preserved ‘Crimson seedless’ bunches during shelf life. PE + PVA-SA 2 mM might be at least partially ascribed to the enhancement of bunches’ quality traits as well as inhibiting cell wall damage during the shelf-life period.

VvERF17 mediates chlorophyll degradation by transcriptional activation of chlorophyll catabolic genes in grape berry skin

Chlorophylls in the skin contribute to grape (Vitis vinifera) berry color and quality. Degradation of chlorophyll occurs during berry development in grape, but less is known about the molecular mechanisms of this process. Here, we characterized an ethylene response factor, VvERF17, as a putative regulator of chlorophyll degradation in grape berry. VvERF17 expression was strongly correlates with development-induced and ETH-triggered chlorophyll degradation. Transient overexpression of VvERF17 in tobacco leaves, tomato fruits, and grape leaves led to color break and chlorophyll degradation, which were resulted from the upregulated expression of chlorophyll catabolic genes (CCGs), including Chlorophyll-b-reductase (NOL), pheophytinase (PPH), pheophorbide a oxygenase (PAO), and red Chlorophyll catabolite reductase (RCCR). Inversely, silencing of VvERF17 in grape leaves partially suppressed the expression of CCGs’ expression. Major CCGs’ expression was closely related to chlorophyll degradation and VvERF17 expression. It was further demonstrated that VvERF17 could activate the expression of major CCGs by directly binding to the ERF binding sites in their promoters. We conclude that VvERF17 mediates chlorophyll degradation by transcriptional activation of NOL, PPH, PAO, and RCCR. These findings elucidate the regulation mechanisms of chlorophyll degradation in grape and enrich our understanding of grape berry color formation.

Grapevine row orientation mediated temporal and cumulative microclimatic effects on grape berry temperature and composition

Ambient radiation and temperature are global drivers of grapevine growth, grape yield and composition, and wine quality. Knowledge of the implications of vineyard row orientation/microclimate is required for decision-making in current and future macro- and mesoclimates. Temporal and cumulative microclimatic changes, induced by vine row orientation (NS; EW; NE-SW; NW-SE) of vertically trellised Shiraz grapevines, on berry pulp temperature and composition at different ripeness levels were investigated. Berries dynamically gained heat energy relative to: ambient climate/weather; direct canopy wall/bunch irradiance; and berry skin colour development. Berries exposed to direct solar radiation during the morning, leading to higher pulp temperatures than ambient, but having a cooling profile after that, resulted in slightly advanced sugar ripening and generally higher skin total anthocyanins and phenols, without significant effects on pH and titratable acidity, at the respective ripeness levels. In contrast, excessive exposure of bunches and those that built up heat, reaching highest temperatures during late afternoon, seemed not conducive to grape composition associated with higher quality. The S, SE, E and NE canopy sides showed consistently higher skin total anthocyanin and phenol contents than their counter sides. Except for acylated forms of peonidin-glucoside, anthocyanin (mono-, acetyl- and coumaroyl-glucosides) accumulation was mostly favoured in berries exposed to exterior canopy sides, but differences in acylated anthocyanins between exterior-facing and interior-facing berries were less than for mono-glucoside anthocyanins. Over-exposure and heat peaking during late afternoon seemed detrimental. Novel information on berry pulp temperature variation in a developing composite grape bunch, exposed to weather and microclimate fluctuation, is provided. An ostensibly homogeneous bunch in reality represents a dynamic berry pulp thermal range at any point in time. Cumulative thermal and radiation impact was evident. This is the first comprehensive attestation on the role of grapevine row orientation (or any viticulture practice) in the management of seasonal nocturnal- and diurnal berry temperature and concomitant composition.

Elevated transcription of transposable elements is accompanied by het-siRNA-driven de novo DNA methylation in grapevine embryogenic callus

BackgroundSomatic variation is a valuable source of trait diversity in clonally propagated crops. In grapevine, which has been clonally propagated worldwide for centuries, important phenotypes such as white berry colour are the result of genetic changes caused by transposable elements. Additionally, epiallele formation may play a role in determining geo-specific (‘terroir’) differences in grapes and thus ultimately in wine. This genomic plasticity might be co-opted for crop improvement via somatic embryogenesis, but that depends on a species-specific understanding of the epigenetic regulation of transposable element (TE) expression and silencing in these cultures. For this reason, we used whole-genome bisulphite sequencing, mRNA sequencing and small RNA sequencing to study the epigenetic status and expression of TEs in embryogenic callus, in comparison with leaf tissue.ResultsWe found that compared with leaf tissue, grapevine embryogenic callus cultures accumulate relatively high genome-wide CHH methylation, particularly across heterochromatic regions. This de novo methylation is associated with an abundance of transcripts from highly replicated TE families, as well as corresponding 24 nt heterochromatic siRNAs. Methylation in the TE-specific CHG context was relatively low over TEs located within genes, and the expression of TE loci within genes was highly correlated with the expression of those genes.ConclusionsThis multi-‘omics analysis of grapevine embryogenic callus in comparison with leaf tissues reveals a high level of genome-wide transcription of TEs accompanied by RNA-dependent DNA methylation of these sequences in trans. This provides insight into the genomic conditions underlying somaclonal variation and epiallele formation in plants regenerated from embryogenic cultures, which is an important consideration when using these tissues for plant propagation and genetic improvement.

Exogenous Calcium Delays Grape Berry Maturation in the White cv. Loureiro While Increasing Fruit Firmness and Flavonol Content.

Vineyard calcium (Ca) sprays have been increasingly used by grape growers to improve fruit firmness and thus maintain quality, particularly in periods of heavy rains and hail. The observation that Ca visibly modified berry size, texture, and color in the most prominent white cultivar of the DOC region ‘Vinhos Verdes’, cultivar (cv.) Loureiro, led us to hypothesize that Ca induced metabolic rearrangements that resulted in a substantial delay in fruit maturation. Targeted metabolomics by ultra-performance liquid chromatography coupled to mass spectrometry and directed transcriptomics were thus combined to characterize the metabolic and transcriptional profiles of cv. Loureiro berries that, together with firmness, °Brix, and fruit weight measurements, allowed to obtain an integrated picture of the biochemical and structural effects of Ca in this cultivar. Results showed that exogenous Ca decreased amino acid levels in ripe berries while upregulating PAL1 expression, and stimulated the accumulation of caftaric, coutaric, and fertaric acids. An increase in the levels of specific stilbenoids, namely E-piceid and E-ω-viniferin, was observed, which correlated with the upregulation of STS expression. Trace amounts of anthocyanins were detected in berries of this white cultivar, but Ca treatment further inhibited their accumulation. The increased berry flavonol content upon Ca treatment confirmed that Ca delays the maturation process, which was further supported by an increase in fruit firmness and decrease in weight and °Brix at harvest. This newly reported effect may be specific to white cultivars, a topic that deserves further investigation.

Early marketable yield and better berry skin color of ‘Redglobe’ grapevines cultivar grown under warm climate by application of Sulis®

Coloration of red grapes under high temperature and narrow day/night temperature range conditions is a great challenge. The aim of the investigation was to test the effect of Sulis® fertilizer which has recently commercially released in Egypt on the color of ‘Redglobe’ grapes. In 2018, the treatments were water (control), 1 ml L-1 Sulis®, or 2 ml L-1 Sulis®. ‘Redglobe’ berries were darker red color due to Sulis® treatments, with no different effect between both Sulis® concentration. While, The 2019 treatments were water (control), 150 mg l-1 ABA + 250 mg l-1 Ethephone, 1 ml L-1 Sulis®+ 250 mg l-1 Ethephone, or 1 ml L-1 Sulis®. During both seasons, the treatments gave the same effect on physical berry characteristics. The bunches sprayed with ABA or Sulis® +ethephone were harvested 10 days earlier than those treated with Sulis® alone, and 20 days earlier than the control clusters. The treatments gave higher packable yield percentages at first pick harvest and SSC/TA ratio than the control. L*, a*, b*, C* and h˚ of berry color traits were decreased due to the treatment applications. Sulis®+ethephone and Sulis® treatments increased the red color index and anthocyanin content in berry skin than the control treatments. Sulis® fertilizers is promising as a coloring agent in grapevines cultivation.

Effect of branch girdling on berry traits, chemical and sensory characteristics of ‘Italia’ and ‘Victoria’ table grapes

ABSTRACT Girdling is an ancient agronomic technique that causes a change in the distribution of photosynthates, mineral nutrients and plant hormones. The aim of this study was to assess the effect of girdling technique on ‘Italia’ and ‘Victoria’ table grape cultivars. In this study, the carpological, physico-chemical and sensory data were evaluated. In order to assess the effect of girdling on grape volatile compounds, a headspace solid-phase microextraction was also performed. Results showed the effects of girdling on morphological, physico-chemical and sensory characteristics of table grapes with a different change of berry size and colour depending on the cultivar. The girdling treatment produced a significant decrease of sugar content and total soluble solids/titratable acidity ratio only for ‘Italia’ cultivar. The analysis of volatile compounds revealed that ‘Italia’ cultivar had three more compounds than ‘Victoria’ and that the samples taken from the girdled grapevines had fewer compounds than their ungirdled ones. The results exhibited that the girdling treatment was more effective on the ‘Italia’ cultivar. This study showed that girdling efficacy strongly depends on the cultivar. The samples from the girdled grapevines had fewer volatile compounds than the ungirdled ones. The Principal Component Analysis totally differentiated both cultivar and treatment without overlap.

Characterization of Tempranillo negro (VN21), a high phenolic content grapevine Tempranillo clone, through UHPLC-QqQ-MS/MS polyphenol profiling

Grapevine cultivar and clone genotype is an important factor in the phenolic composition of wine. In this study, a new intense dark black berry color variant of Tempranillo, known as Tempranillo negro or VN21, is described. A targeted chromatographic approach based on UHPLC-QqQ-MS/MS was used to study the anthocyanins and non-colored phenols of the grape berry (skin and seeds) and wine. RJ43, one of the most cultivated clones in D.O.Ca. Rioja (Spain), was analyzed for comparison. Results suggest that the unique color of the grape skin in Tempranillo negro could be explained by higher concentrations of peonidin and cyanidin derivatives. This genotype accumulated anthocyanins in the seeds. Those differences in the berry were enhanced in the VN21 wines, which displayed notably higher concentrations of anthocyanins, and significantly increased contents of proanthocyanidins and stilbenes. This study exemplifies the application of phenol chromatographic analyses of spontaneous somatic variants to grapevine clonal selection.

Effects of Several Preharvest Canopy Applications on Yield and Quality of Table Grapes (Vitis vinifera L.) Cv. Crimson Seedless.

Modern viticultural areas are being confronted with the negative impacts of global warming on yield and fruit composition, with especially adverse effects on anthocyanin synthesis. Novel and sustainable tools, such as biostimulants, may represent a viable alternative to traditional cultural practices, thus promoting eco-friendly strategies to enhance the yield, fruit quality and abiotic stress tolerance of grapevines. ‘Crimson Seedless’ is a late-season red table grape variety, and due to climatic warming, its berries are frequently failing to acquire the commercially acceptable red color. Canopy applications of different biostimulants, namely, Kelpak®, Sunred®, Cytolan®, LalVigne™ Mature as well as Ethrel® Top, were tested on grapevine cv. Crimson Seedless grown under semi-arid Mediterranean conditions in order to evaluate their effects on yield and fruit quality. Some of the products were sprayed in canopies at labeled doses, and some were applied at doses reported in other studies. For the control treatment, canopies were sprayed with water. Sampling started at veraison and was repeated at 10-day intervals to measure the evolution of berry weight, length and diameter, as well as the total soluble solids and titratable acidity of the juice. The grapes were harvested when the berries of one of the treatments attained the commercially acceptable color. The greatest improvements in the red berry color were achieved with Sunred® (at a dose of 4 L ha−1) and Ethrel® Top (250 ppm plus glycerol at 1%), each applied at veraison and 10 days later. The different applications had varying effects on productivity and qualitative parameters. Only Sunred® improved the accumulation of anthocyanin and the overall acceptability of table grapes by consumers. The obtained results clearly demonstrate that applying Sunred® can improve the yield and qualitative parameters of the red table grape variety ‘Crimson Seedless’, indicating that this biostimulant could be a viable alternative to the most widely used plant growth regulator, ethephon.

Floricane yield and berry quality of seven primocane red raspberry (Rubus idaeus L.) cultivars

Primocane raspberry (Rubus idaeus L.) may produce crop on the lower part of the cane during the second year of its’ growth cycle, if the canes are retained over winter. We aimed to evaluate the floricane cropping potential and berry quality in seven primocane raspberry cultivars, which are too late for fall cropping in the Northern growing conditions. Long cane plants of these cultivars were produced, overwintered, and grown like floricane cultivars in a high tunnel. Harvesting floricane crop started in mid-June, and the length of the summer cropping season was between eight to 10 weeks. 'Joan J' and 'Imara' were the earliest cultivars, and 'Autumn Bliss' was the latest. Total floricane yield in most cultivars was between 1.7 to 2.0 kg/cane. ‘Autumn Treasure’ yielded significantly less, and ‘Autumn Bliss’ produced 2.5 kg berries /cane. The average berry size was 5 g, except in ‘Autumn Bliss’ and ‘Autumn Treasure’, which had smaller berries. The highest sugar content was observed in 'Kwanza' berries and the lowest in 'Polka'. High throughput phenotyping proved an effective tool for determining berry shape and color. ‘Kwanza’ berry color was the reddest, yellowest and lightest of all cultivars. Based on our results, growing primocane raspberry cultivars as long cane plants for production of summer crop is more reliable than growing them as fall cropping in short growing season conditions. The cultivars ‘Imara’ and ‘Kweli’ were the most promising in our experiment; they had a high yield potential and excellent berry quality.