Vine Productivity Research Articles

A Review on Production and Marketing of Betel Vine

Betel Vine is grown widely across the country, playing an essential role in social, religious, and cultural activities and significantly contributing to the economy through employment and foreign exchange. This review article on Betel Vine, a significant economic and heritage crop in India, employs a systematic literature review to analyze and synthesize existing research on its production and marketing. Betel Vine, with its heart-shaped leaves known as "Paan," provides substantial employment and foreign exchange. The review identifies that the marketing of Betel leaves faces unique challenges due to their perishable nature and specific regional preferences. The systematic literature review provides a comprehensive understanding of the trends, challenges, and opportunities in Betel Vine production and marketing. Key findings indicate significant economic contributions from states like Karnataka, Tamil Nadu, and West Bengal. The review also identifies research gaps, such as the need for improved marketing strategies and better management of production challenges. Future research should focus on developing value-added products, enhancing marketing efficiency, and addressing health concerns associated with Betel chewing. The conceptual framework guides the review process, synthesizing diverse literature to facilitate a structured and comprehensive analysis. The outcomes suggest that effective strategies for enhancing the Betel Vine industry should address these identified gaps and leverage opportunities to boost economic growth and support rural communities.

How pruning season affects the phenology of Vitis sp. cultivated in a semiarid climate

The pruning time for Vitis vinifera sp. is determined by environmental factors that affect the level of hormones in the plant and, consequently, control metabolic changes. Inducing meristematic activity and altering the phenology of the vine. However, a drastic reduction in the yield of excessively pruned vines has been observed with potential effects not only for the current season but also for subsequent seasons, due to the decrease in the plant's reserves. Thus, this review provides a comprehensive discussion on how pruning time affects the phenology of vines grown in a semi-arid climate, highlighting how environmental factors regulate vine growth in regions with a semi-arid climate, and which strategies can be used for cultivation in this region. Estimating the best pruning time encourages better practices and timely actions to improve vine productivity and grape quality. Therefore, this study provides important information for planning grapevine cultivation at different pruning times.

Could 101-14 Mgt Rootstock Affect Post-Spring Frost Vine Developing? Preliminary Findings

(1) Background: Spring frost damage is a common phenomenon that occurs in Southern Chile that considerably affects vine productivity and grape quality. (2) Methods: A field trial was conducted in order to study vine phenology and berry physicochemical parameters in Chardonnay, Sauvignon Blanc and Pinot Noir ungrafted and grafted (onto 101-14 Mgt rootstock) grapevines after a spring frost. This event killed the totality of primary bud shoots when the vines reached the phenological stage of unfolded leaves. (3) Results: From budburst, to flowering of secondary bud shoots, ungrafted Sauvignon Blanc grapevines presented an advanced phenology, whereas 101-14 Mgt rootstock tended to advance the maturity of Pinot Noir grapevines from flowering to ripening of berries. At harvest, berries from secondary buds of vines grafted onto 101-14 Mgt rootstock showed higher soluble solids than the ones from ungrafted Chardonnay and Sauvignon Blanc vines. High total phenolic content was found in berries from secondary buds of the grafted vines, compared to the ones from the ungrafted vines. Berry soluble solids variability tended to statistically decrease toward harvest in the studied plant materials, and the maximum coefficient of variation for soluble solids, berry weight, berry firmness and berry size reached 9.5%, 25.9%, 18.6% and 8.9%, respectively. (4) Conclusions: These preliminary results may be interesting for the Southern Chilean viticulturists since it seems that 101-14 Mgt rootstock could affect phenology and grape berry maturity of grapevines established in the Cautín Valley after spring frost damage.

Effect of different deficit irrigation regimes on vine performance, grape composition and wine quality of the “Primitivo” variety under mediterranean conditions

Climate change represents one of the current major challenges and the improper use of water resources is an impeding threat. Agricultural research can play a crucial role by developing innovative strategies and techniques to reduce water use without affecting crop productivity and quality, particularly in grapevine growing in Mediterranean areas, as both productivity and wine quality are quintessential for the economic and ecologic sustainability of this crop. The present study aimed to define a deficit irrigation strategy for the “Primitivo” grapevine cultivar, taking into account the overall pathway of the vineyard performance in terms of leaf functionality, starch reserves, vine productivity, and wine quality. The trial was carried out in Southern-Italy on a three year-old, drip irrigated vineyard, imposing four deficit irrigation regimes for two consecutive seasons, consisting of 29 (T29), 55 (T55), 85 (T85) and 100% (T100) of crop evapotranspiration (ETC). Mild water restriction (T85) did not affect vegetative nor reproductive vine performance. Deficit irrigation at 55% ETC lowered leaf functionality, starch accumulation, vine vigour and yield, due to a reduction of cluster weight; however, wine acidity and phenolic compounds were increased. T29 further decreased yield, as also the number of clusters was reduced. The most water-stressed treatment revealed a low concentration of malic acid in the must and a consequent increase of the ethanol sensation in the wine. After 9 months ageing, T85 had the highest wine colour intensity suggesting this treatment as the most promising in terms of quality and quantity of wine as well as for water saving.

Analysis of Economic Efficiency: Case of Sweet Potato Seed Vine Production in Homabay County, Kenya

Sweet potatoes are not only a nutritious, high value food for the daily diet, but also an important source of income. In the selected survey areas in the Lake Region of Kenya, sweet potato is amongst the major commercially grown crops. Therefore, in order to understand the profitability and performance of sweet potato producers in the study area, this study was implemented. Sweet potato is one of the main commercially produced crops in the selected survey areas in the lake region of Kenya. Therefore, this study was conducted to understand the profitability and performance of sweet potato producers in the study areas. The study employed Cost Function in the analyses of Economic Efficiency of Sweet Potato Seed Vine Production system in Kenya. A multi-stage random sampling technique was used to select sample size of 150 sweet potato vine producers for this study. By use of a structured questionnaire, data was collected on production input, output, input and output prices, characteristics of sampled farmer and plot. Using the maximum likelihood method, the variables of the cost function were estimated. Result revealed that the farm level cost- efficiency was about 56 percent. The research has shown that age and farm size were negative but significantly related to cost-efficiency at ten and one percent respectively. Gender, farming experience, Education, access extension to and credit were positive but significantly associated with cost-efficiency at one percent. The study advocates for policy decision that youthful farmers be inspired to venture into SP vine production and the government to enhance access to education, credit and extension services the ongoing farming.

Modulating ‘Xinomavro’ (Vitis vinifera L.) Vine Growth and Berry Composition: A Comparative Analysis of Rootstock Effects

Rootstocks serve as a strategic tool for grapevine adaptation to specific biotic and abiotic conditions and for managing vine growth, grape yield, and berry composition in commercial vineyards. This study investigates the influences of four different rootstock varieties (101-14 MGt, 3309 C, 110 R, and 140 Ru) on the viticultural performance of ‘Xinomavro’ vines, a prominent Greek red winegrape varietal. By conducting a two-year field experiment using various rootstocks, we assessed parameters related to water status, vegetative growth, yield, and berry composition. Our results revealed that rootstock selection has a significant impact on vine development, especially in terms of berry size and the concentrations of secondary metabolites. Principal component analysis confirmed the complex interaction between rootstock vigor and vine productivity. This study underscores the importance of rootstock variety in manipulating grapevine characteristics, particularly for the ‘Xinomavro’ variety, in response to regional climatic conditions.

Root-mycorrhizae species and variety pairing matters: A study case with arbuscular mycorrhizal fungi communities and Vitis vinifera varieties in the southern Brazil

Vitis vinifera varieties can change the arbuscular mycorrhizal fungi (AMF) community structure in their rhizosphere. Our aim here was to present a quantitative analysis of the AMF species associated with V. vinifera varieties from Cabernet, Merlot, and Sauvignon groups in a subtropical Cambisol, Southern Brazil. Eight V. vinifera varieties were selected for the field experiment from September 2019 to June 2021. For each studied variety, we established five rectangular plots (60.0 × 14.0 m) using a randomized block design with seven blocks. We found seven main groups considering the dissimilarities of AMF spores: i) Entrophospora claroidea in the root zone of C. Eidos and C. Volos (both varieties from the Cabernet group); ii) Funneliformis mosseae in the root zone of Fleurtai; iii) Racocetra coralloidea in the root zone of Merlot Khantus; iv) Scutellospora calospora in the root zone of M. Khorus; v) Quatunica erytrophus in the root zone of Sauvignon Kretos; vi) Glomus coremioides in the root zone of S. Rytos; and vii) Acaulospora tuberculata in the root zone of Soreli. The results of our study highlighted the importance of considering V. vinifera varieties as potential hosts for specific AMF species by creating an AMF-host pairing specificity to improve root colonisation and plant yield in their own advantage. Thus, field experiments considering V. vinifera varieties into agrosystems for vine production contribute to our understanding of the AMF symbiosis in subtropical soils.

Pedological formations on old mountain geomorphological surfaces of central Spain

The chemo-morphological properties of soils on ancient landforms (quarzitic pliocene alluvial fans, pleistocene terraces), namely “rañizos”, on middle-high mountains (Eastern-Central System, Iberian Peninsula, Rio Negro, Cogolludo) were investigated. Several properties were analyzed by standard procedures. A detailed soil diagnostics and classification on “rañizos” were done, unlike those widely studied on “rañas” (similar landform), by identifying parallel pedogenetic processes in both formations. The genetic and geographic features of Alfisols, Ultisols and Inceptisols are closely related to the nature of their parent materials, based on quartzite and quartz conglomerates, sometimes with an arkosic matrix, red shale, polygenic gravels and pebbles. Soil features were determined by genuine soil-forming inherent lithological rock properties. Other driving factors were flat topography and enough soil formation time to allow intense pedogenesis. The main soil-forming processes were intense weathering, clay enrichment horizons with illuviation, red color caused by iron oxide dehydration and signs of pseudogleyzation processes. Such pedological formations can be considered endemisms; that is, “rare” soils and, up to a point, “relict”. The soil reaction is acid/slightly acid with low base saturation. Despite lying on mountains, soils are characterized by moderate-low organic matter content. Soil conditions and climate provide good vine production requirements despite acidity levels. A common feature of all Rio Negro soils is the presence of gravel (size up to 3–5 cm), which is evenly distributed on arable layers. The results can be used to assess vineyard soil use in a potential Pago (Protected Denomination of Origin) and to extend the database of vineyard soils from poorly studied Mediterranean continental mountain regions.

Multi-Omics Analyses Unravel Metabolic and Transcriptional Differences in Tender Shoots from Two Sechium edule Varieties.

Chaylte vine, the tender shoot of Sechium edule, is popular among vegetable consumers because of its high nutritional content, crisp texture, and unique flavor. Existing studies on the nutrient composition of chaylte vines are mostly simple chemical determinations, which have limited the breeding of specialized cultivars and the development of related industries. Using metabolomics combined with transcriptomics, this study analyzed the metabolic characteristics and related molecular mechanisms of two common varieties of chaylte vines: green-skinned (SG) and white-skinned (SW). Between the two varieties, a total of 277 differentially accumulated metabolites (DAMs) and 739 differentially expressed genes (DEGs) were identified. Furthermore, chemical assays demonstrated that the SW exhibited a higher total flavonoid content and antioxidant capacity. In conclusion, it was found that the SG samples exhibited a higher diversity of flavonoid subclasses compared to the SW samples, despite having a lower total flavonoid content. This inconsistent finding was likely due to the differential expression of the phenylalanine ammonia-lyase (PAL) and chalcone synthase (CHS) genes in the two varieties. These results laid the foundation for investigating the mechanisms involved in flavonoid regulation and the breeding of specialized S. edule cultivars for chaylte vine production.

Exploring the relationship between leaf water potential, defoliation, and grape berry physical properties of Merlot (Vitis vinifera L.) grapevine

The aim of this study was to examine the impact of leaf water potential and defoliation treatments on the physical properties of grape berries. The research was conducted over two consecutive years (2019-2020) using ‘Merlot’/41B graft combination grapevines grown in the Chateau Kalpak vineyards located in Tekirdağ, Şarköy. The experiment involved four distinct water stress levels (S0, S1, S2, and S3), which were determined based on leaf water potential measurements. These stress levels were subjected to different irrigation levels. Additionally, defoliation treatments were applied, including Control (C), Full Window (FW), Right Window (RW), and Left Window (LW). The results showed that the effects of water stress and defoliation treatments on berry physical properties were statistically insignificant. However, in the second year of the study, the FW treatment was observed to have led to changes in the desired direction for grapevines. This was likely due to the cumulative decrease in water reserves caused by reduced precipitation over multiple years, making the effects of FW treatment more prominent. Moreover, the study found that both current and past vegetation period conditions influence vine production year, leaf water potentials (Ψleaf), and stress levels. Finally, the data revealed that berry weight and % dry weight increased with higher stress levels.

Grapevine dieback caused by Botryosphaeriaceae species, Paraconiothyrium brasiliense, Seimatosporium vitis-viniferae and Truncatella angustata in Piedmont: characterization and pathogenicity

Grapevine Trunk Diseases (GTDs) are major threats in Mediterranean countries, causing economic losses due to reduced grape yields and long-term vine productivity, as well as death of grapevines. A survey was conducted in Piedmont (Northern Italy) during 2021-2022 to investigate the species diversity and distribution of GTD pathogens in this important Italian wine region. Morphological and multi-locus phylogenetic analyses (based on ITS, tef1, tub2, act and rpb2) identified species of Botryosphaeriaceae at high frequency, including Botryosphaeria dothidea, Diplodia mutila, Diplodia seriata and Neofusicoccum parvum. Other pathogens commonly associated with GTDs, including Eutypa lata, Fomitiporia mediterranea and Phaeomoniella chlamydospora, were also isolated. Less commonly isolated species included Neocucurbitaria juglandicola, Paraconiothyrium brasiliense, Seimatosporium vitis-viniferae and Truncatella angustata. Pathogenicity tests with two representative isolates of each species were carried out using one-year-old potted grapevine cuttings (‘Barbera’). All isolates (except N. juglandicola) caused brown wood necrotic vascular discolourations on inoculated plants and were successfully re-isolated. Effects of temperature on colony growth were also assessed. For all tested isolates there was no growth at 5°C, only four isolates (Botryosphaeriaceae) grew at 35°C, and optimum growth temperatures were between 20 and 25°C. This is the first record of Paraconiothyrium brasiliense and Neocucurbitaria juglandicola associated with symptomatic grapevines in Italy.

Effects of the Annual Nitrogen Fertilization Rate on Vine Performance and Grape Quality for Winemaking: Insights from a Meta-Analysis

Sustainability in grapevine cultivation requires the precise use of water and fertilizers, particularly nitrogen (N), to produce grapes of the highest quality for winemaking, while simultaneously avoiding harm to the surrounding waters and atmosphere by reducing NO3− losses and N2O and NH3 emissions from the vineyards. To address the challenge of optimizing N use in viticulture, many N fertilization trials have been carried out over the last decades, and a compilation and analysis of worldwide trials was therefore needed. The present study tackled this challenge through a meta-analysis of published research, which included 374 fertilization trials. From the compiled data, six vine production parameters and eight grape quality traits were extracted and normalized to enable comparisons between experiments. The Mitscherlich law of diminishing returns was able to satisfactorily describe the set of vine production parameters against nitrogen application rate, and the same occurred with the yeast assimilable nitrogen (YAN). In vines, both reproductive and vegetative growth similarly responded to the N application rate. In general, the nitrogen requirements for 95% of the maximum grape yield amounted to rates between 30 and 40 kg·N·ha−1, which increased nitrogen use efficiency (NUE) to values between 0.27 and 0.36 t·kg·N−1. Although several grape quality traits could not be described against the N rate in terms of any mathematical relationship, an N rate between 20 and 25 kg·N·ha−1 could be considered as maximizing grape quality for winemaking. Such N fertilization range increases NUE up to values between 0.41 and 0.47 t·kg·N−1, thus almost doubling the known NUE standards when grape quality is targeted instead of yield, although soil fertility could be exhausted in the mid-to-long term. Whatever the case, anthocyanins and polyphenols are well preserved in red grapes at such low N rates, although YAN is not. The results of this work will be useful for guiding new vine N nutrition research and N nutrition management in vineyards, thus increasing wine growing sustainability.

Grapevine plantlets respond to different monochromatic lights by tuning photosynthesis and carbon allocation.

The quality of planting materials is the foundation for productivity, longevity, and berry quality of perennial grapevines with a long lifespan. Manipulating the nursery light spectrum may speed up the production of healthy and high-quality planting vines but the underlying mechanisms remain elusive. Herein, the effects of different monochromatic lights (green, blue, and red) on grapevine growth, leaf photosynthesis, whole-plant carbon allocation, and transcriptome reprograming were investigated with white light as control. Results showed that blue and red lights were favorable for plantlet growth in comparison with white light. Blue light repressed excessive growth, significantly increased the maximum net photosynthetic rate (Pn) of leaves by 39.58% and leaf specific weight by 38.29%. Red light increased the dry weight of the stem by 53.60%, the starch content of the leaf by 53.63%, and the sucrose content of the stem by 230%. Green light reduced all photosynthetic indexes of the grape plantlet. Photosynthetic photon flux density (PPFD)/Ci-Pn curves indicated that blue light affected photosynthetic rate depending on the light intensity and CO2 concentration. RNA-seq analysis of different organs (leaf, stem, and root) revealed a systematic transcriptome remodeling and VvCOP1 (CONSTITUTIVELY PHOTOMORPHOGENIC 1), VvHY5 (ELONGATED HYPOCOTYL5), VvHYH (HY5 HOMOLOG), VvELIP (early light-induced protein) and VvPIF3 (PHYTOCHROME INTERACTING FACTOR 3) may play important roles in this shoot-to-root signaling. Furthermore, the correlation network between differential expression genes and physiological traits indicated that VvpsbS (photosystem II subunit S), Vvpsb28 (photosystem II subunit 28), VvHYH, VvSUS4 (sucrose synthase 4), and VvALDA (fructose-bisphosphate aldolase) were pertinent candidate genes in responses to different light qualities. Our results provide a foundation for optimizing the light recipe of grape plantlets and strengthen the understanding of light signaling and carbon metabolism under different monochromatic lights.

Combined use of sticky traps and biopesticides as a sustainable tool to manage Aleurocanthus rugosa (Hemiptera: Aleyrodidae) infesting betel vine

The betel vine (Piper betle L.) is one of the plantation crops commercially cultivated for its leaf in South and Southeast Asia. The leaf production is often threatened by different insect pests including Aleurocanthus rugosa Singh (Hemiptera: Aleyrodidae). Currently, infestations of A. rugosa in betel vine are primarily controlled using excessive conventional broad-spectrum chemical pesticides that pose serious human health risks due to the masticatory nature of consumption. This study was carried out to investigate the performance of colored sticky traps and biopesticides against A. rugosa as an ecofriendly approach by conducting multilocation field trials from 2019 to 2021. It was observed that the A. rugosa population prevailed throughout the year, however, insect infestation was higher in May and October due to the high temperature. Among the sticky traps, A. rugosa was highly attracted to the yellow-colored traps compared to white or blue traps. Whereas alternating sprays of either D-lemonine (Bio clean® 5% SL) or spinosad (Success® 2.5% SC) with sodium lauryl ether sulphate (Fizimite® 10%) reduced the A. rugosa population by 71.4–79.0% over control. Further, a combination of these spray regimes with yellow-colored sticky traps as IPM packages showed improved results in reducing pest populations by 83.8–86.0% and increasing leaf yield by 60.4–63.6% over control. Even the performance of the IPM packages was better than farmers’ practice i.e., broad-spectrum chemical pesticides. Thus, the outcome of this study indicates that the IPM program could be a sustainable and environmentally friendly method of controlling A. rugosa in betel vine production.

Comparative mathematical analysis of economically important ampelographic indicators in white wine vine varieties (Vitis vinifera L.)

A comparative mathematical analysis of economically important ampelographic indicators was performed in 32 local, introduced and newly bred white wine vine varieties. It was found that depending on the similarity and remoteness of the values of the studied indicators, the varieties are grouped into three generalized clusters. In the first, the varieties are characterized by a longer budding period and relatively lower productivity. In the second, they have similarities in the length of the budding period, long period of budding - technological maturity, moderate productivity, and close content of volatile acids in the wine. In the third, the newly bred two varieties Gergana and Misket Markovski, which are the most fertile and productive and with the smallest number of seeds in the berries. There is a high variability of the individual white wine varieties according to the studied economically valuable indicators. The indicators of bunch length and average weight per 100 berries have a stronger direct effect on the formation of the yield in individual varieties, and the average bunch weight, bunch width, percentage of mesocarp in berries, berry length and width, as well as the theoretical yield significantly affect indirectly the productivity of vines.

Resistant rootstocks mitigate ionic toxicity with beneficial effects for growth and photosynthesis in grapevine grafted plants under salinity

The identification of salt-tolerant rootstocks can be an important strategy for producing vines in salt-affected areas. In this study, was tested the hypothesis that resistant rootstocks can mitigate the salinity damages by the lower ionic toxicity associated to best growth and photosynthesis in grapevine grafted plants. The four grapevine (Vitis spp.) rootstocks (‘IAC 313,’ ‘IAC 572,’ ‘SO4’ and ‘1103P’) and the grafted plants of ‘BRS Vitória’ variety on these rootstocks were exposed to increase NaCl (0, 40 and 80 mM NaCl) for the salt treatments. Under salinity, ‘IAC 313′ and ‘IAC 572′ rootstocks showed lower Na+content and higher K+ levels in leaves relative to other rootstocks. This response was associated with a higher leaf K+/Na+ ratio in the grafted and nongrafted plants of the ‘IAC 313′ and ‘IAC 572′ rootstocks. Based on the root and leaf dry weight (DW), the growth of the ‘IAC 313′ rootstock was unaffected by salinity, while ‘IAC 572′ showed a lower loss of DW relative to 1103P and SO4 rootstocks. All four rootstocks experienced increased membrane damage under saline conditions, but lipid peroxidation was lower in the ‘IAC 313′ rootstock. Grape plants grafted with the ‘BRS Vitória’ variety onto the IAC rootstocks (Vit/IAC 313 and Vit/IAC 572) presented higher efficiency of gas exchange and electron flow under salt stress, traits that were influenced by the rootstock genotype. Photochemical quenching (qP) and the electron transport rate (ETR) decreased under saline conditions, a response that was more intensive in Vit/1103P plants. In summary, our data showed that among evaluated rootstocks the ‘IAC 313′ and ‘IAC 572′ are better acclimated to salt and can be considered for vine production in salt-affected areas.

Application of seaweed and pruning residue as organic fertilizer to increase soil fertility and vine productivity

AbstractAlgae have an indisputable role in coastal ecosystems, but their accumulation and uncontrolled proliferation cause severe damage for the local municipalities. Fertilization with seaweed has been shown to increase soil fertility and crop production reducing ultimately the need for inorganic fertilizers. However, contradictory results of the compost effect have been reported. In the present work, we aimed at testing the suitability of three composted algae materials obtained in a previous study as soil amendments for vines. The composted materials consisted of pruning waste (P) and seaweed (S) mixed (henceforth, P2S1, P1S1 and P1S2, referring the number to the ratio of P to S). Overall, we observed an increase in soil organic matter, phosphorus (P) and potassium (K) in the soil treated in comparison with soils with inorganic fertilization. A moderate N soil enrichment (ca. 20%) was also detected. The leaf analysis reflected generally the greatest concentrations of NPK for the organic treatments, but this was remarkable only during the first year after seaweed application. A noticeable improvement in grape production was detected especially with the P1S1 compost without compromising grape quality although a decrease in sucrose content was noted with the compost with higher productivity (e.g. P2S1 and P1S1). This slight sucrose drop could be attributable to a greater water availability mediated by the compost or to a dilution factor of the sucrose content caused by a greater number of berries in those vines. These findings suggest that although monitoring of the long‐term effects is needed, the use of seaweed amendments for agriculture could offer a cost‐effective method for coastal municipalities to reduce excessive algae debris while also minimizing the impacts of inorganic fertilization.

A systemic approach to grapevine decline diagnosed using three key indicators: plant mortality, yield loss and vigour decrease

Grapevine decline, a major global viticulture issue, is defined as a multi-year decrease in vine productivity and/or increase in vine mortality. Although grapevine trunk diseases are one of the most-studied causes, decline is multifactorial and associated with more than 70 factors, including abiotic and biotic hazards. With so many factors to consider, the phenomenon difficult to understand, especially for winegrowers. Our study aims to make it easier to determine and assess grapevine decline by focusing on three key indicators: yield, mortality and vegetative vigour. We investigated the relationships between these indicators from both a temporal and spatial perspective to propose a set of diagnostic indicators. Thus, we conducted a winegrowers’ survey, an historical analysis of grapevine decline and field measurements of the abovementioned indicators on plot networks in three major French winegrowing regions (see graphical abstract): Bordeaux, Cognac and Languedoc. We found that farmers’ perceptions of decline were consistent with an objective characterisation of decline based on in-field measurements of the indicators. Although vine mortality progressively spread over the years, neither the survey nor the historical analysis showed a direct link between decline and yield loss. Rather, large yearly fluctuations in yield, which did not systematically decrease over time, account for this finding. As a result, the mortality rate and the normalised difference vegetation index (NDVI) indicators were shown to be earlier indicators of grapevine decline than yield loss (yield achievement ratio, YAR). We performed a multifactorial analysis of the overall data set from the three regions to deepen our understanding of the variety of declining situations and the underlying environmental and management factors contributing to decline. Finally, two ground-based NDVI indicators and an image-analysis methodology using aerial photographs were proposed as easy-to-obtain indicators of grapevine decline. NDVI indicators were linearly correlated to both YAR and mortality rate. This study provides a better understanding and promising tools for early diagnosis of grapevine decline.

Risk Assessment and Limiting Soil Factors for Vine Production—Cu and Zn Contents in Vineyard Soils in Galicia (Rías Baixas D.O.)

Characteristics of vineyard soils and management practices can be assessed to determine the soil trend evolution, risks, and limits of soils for vine production through soil factors and foliar diagnosis. This study was made with soils from a vineyard divided into two plots belonging to the Rías Baixas D.O. The vineyard soils were sampled and characterized for three years. The total and available Cu and Zn contents and the physicochemical characteristics of the soils were determined annually and every four months, respectively. The main objective was to assess edaphic properties, phytosanitary treatments, fertilization, and tillage applied to indicate the quality of the vineyard soils. The soils presented certain limitations associated with mechanization, trafficability, and ease of tillage for cultivation. The soils showed a sandy loam texture, which makes the application of compost necessary to improve water retention and cation exchange capacity. Phytosanitary treatments and fungicides caused phytotoxic contents of Cu and Zn in the soils without being detrimental to the vines. In conclusion, the edaphic factors and foliar analysis were adequate to evaluate the condition of the soils and vines and to establish the necessary measures to improve the edaphic conditions of the vineyard soils to improve plant production.

Ratooning increases production of sweetpotato seed vines multiplied in insect-proof net tunnels in Tanzania

Summary Insect-proof net tunnels can help reduce virus infection of clean virus-tested sweetpotato seed produced by decentralized seed producers. However, optimal management is required to maintain both quality and quantity of seed produced. This study investigated the effect of the ratoon cropping technique on vine production in net tunnels and open fields. Virus-tested planting material of two varieties, Kabode and Mataya, were grown in net tunnels and open fields. Each variety had 80 plants per plot, with 40 following the ratooning technique and 40 a replanting technique. The ratooned crop was harvested six times, comprising the initial harvest and five regrowths. This covered 14 months representing six generations of vine production. The number of vines, number of nodes per vine, and vine length were recorded. The number of plants showing virus symptoms was also recorded. The ratoon cropping technique produced more vines compared with the replanting technique in both net tunnels and open fields. Cv. Kabode produced more vines in open fields compared with net tunnels regardless of cropping technique. On the other hand, cv. Mataya produced relatively equal numbers of vines in net tunnels and open fields. Despite ratooning leading to more vine production compared with replanting, the technique led to higher virus incidences on plants grown in the open. This also varied with variety with the highest virus disease incidences being recorded on cv. Mataya. We recommend the ratoon cropping technique for sweetpotato vine production in net tunnels. Replanting technique should be adopted for vine production in the open fields because it acts as a key control strategy for virus infections even for susceptible varieties.