J.B. Royo

Are precision agriculture tools and methods relevant at the whole-vineyard scale?

Precision viticulture (PV) has been mainly applied at the field level, for which the ability of high resolution data to match within-field variability has been already shown. However, the interest of PV for grape growers would be greater if its principles could also apply at a larger scale, as most growers still focus their management on a multi-field scale, not considering each field as an isolated unit. The aim of this study was to analyse whether it is possible and relevant to use PV tools to define meaningful management zones at the whole-vineyard scale. The study was carried out on a 90-ha vineyard made of 27 contiguous fields. The spatial variability of vine vigour, estimated with the Normalized Difference Vegetation Index (NDVI), was analysed at within-field and whole-vineyard scales. The spatial variability of the vigour was significant and spatially organized whatever the considered scale. Besides, vineyard spatial variability was characterised using information on environmental factors (soil apparent conductivity and elevation) and vine response (yield, vigour and grape composition). At both scales, NDVI and measured environmental factors were used to establish a three-level classification, whose agronomic significance was tested comparing the vine response observed for each class. The analysis of high resolution information allowed the definition of classes with agronomic and oenological implications, although there was not a straightforward correspondence between the classes defined and quality. Analysing the variability at the whole-vineyard scale highlighted a trend of spatial variation associated to elevation that was hardly visible at the within-field level.

The use of isoenzymes in characterization of grapevines (Vitis vinifera, L.). Influence of the environment and time of sampling

Abstract Isoenzymes from grapevine woody stems and shoots were evaluated for their use in identification of varieties and clones. Plant extracts were separated by polyacrylamide gel electrophoresis. Isoenzyme analysis was carried out for esterases, peroxidases, catechol oxidase, glutamate oxalacetate transaminase and acid phosphatase. The plant material was grown and sampled at two localities in Spain, with different climatic conditions. Sampling was carried out bimonthly for two consecutive years in order to find out the influence of the environment and time of the year. Each isozyme system had a pattern defined by ‘fixed’ bands, that were always present at both localities and during the resting period of the plant (fall—winter). Esterases had a pattern with very few ‘fixed’ bands. Catechol oxidase was the most polymorphic system, thus being highly discriminating. The studied isoenzyme systems gave differences among varieties, although not among clones of the same variety. The use of this methodology for identification of grapevine plant material is discussed.

Vegetative Growth, Reproductive Development and Vineyard Balance

In the last decades, viticultural research has made important progress due to the implementation of many technical advances to this field. In addition to “classical” viticultural research, it is now possible to analyze vine behaviour with many different approaches, such as plant physiology, genomics, proteomics, precision viticulture and so on. These changes extend our understanding of viticulture, but they may also lead to a certain heterogeneity in the methodology used to estimate the basic characteristics of the vineyards (e.g.: vegetative and reproductive growth). Even worse, measurements of those parameters are sometimes neglected. In order to optimize the relevance and inter-disciplinarity of our work, and its applicability to the vineyard, we should tend toward protocol standardization, the most suitable measurements and ways of expressing results should be determined for each circumstance. This chapter attempts to shed some light on some methodological aspects related to the measurement of vine vegetative and reproductive growth and vineyard balance. We have tried to be comprehensive, but not exhaustive, since some topics are also the subject of other chapters in this book whereas others are beyond its scope.

Evaluating the Influence of the Microsatellite Marker Set on the Genetic Structure Inferred in Pyrus communis L.

Fingerprinting information can be used to elucidate in a robust manner the genetic structure of germplasm collections, allowing a more rational and fine assessment of genetic resources. Bayesian model-based approaches are nowadays majorly preferred to infer genetic structure, but it is still largely unresolved how marker sets should be built in order to obtain a robust inference. The objective was to evaluate, in Pyrus germplasm collections, the influence of the SSR marker set size on the genetic structure inferred, also evaluating the influence of the criterion used to select those markers. Inferences were performed considering an increasing number of SSR markers that ranged from just two up to 25, incorporated one at a time into the analysis. The influence of the number of SSR markers used was evaluated comparing the number of populations and the strength of the signal detected, and also the similarity of the genotype assignments to populations between analyses. In order to test if those results were influenced by the criterion used to select the SSRs, several choosing scenarios based on the discrimination power or the fixation index values of the SSRs were tested. Our results indicate that population structure could be inferred accurately once a certain SSR number threshold was reached, which depended on the underlying structure within the genotypes, but the method used to select the markers included on each set appeared not to be very relevant. The minimum number of SSRs required to provide robust structure inferences and adequate measurements of the differentiation, even when low differentiation levels exist within populations, was proved similar to that of the complete list of recommended markers for fingerprinting. When a SSR set size similar to the minimum marker sets recommended for fingerprinting it is used, only major divisions or moderate (F ST>0.05) differentiation of the germplasm are detected.

Analysis of the genetic diversity and structure of the Spanish apple genetic resources suggests the existence of an Iberian genepool

87 Pags.- 3 Tabls.- 5 Figs.- 1 Suppl. Fig.- 5 Suppl. Tabls. The definitive version is available at: http://onlinelibrary.wiley.com/journal/10.1111/(ISSN)1744-7348

Agronomic significance of the zones defined within vineyards early in the season using NDVI and fruit load information

Wine quality is known to be highly dependent on grape quality and, therefore, wineries aiming to produce premium wines are concerned with obtaining top quality grapes. However, since grape quality is not uniform within a vineyard sometimes it is necessary to evaluate which zones within a single vineyard are producing the best grapes in order to segregate them at harvest. The aim of this work was to compare the performance of two methods to delineate zones within vineyards: (1) expert knowledge (ExpZ); and (2) fuzzy k-means analysis (FuzZ) using NDVI and fruit load as information sources, procedures that were applied to 4 adjacent vineyards located in Villamanta, (Madrid, Spain). Both methodologies were suitable to delineate parts of a vineyard with differences in grape composition, although FuzZ provided a more significant zoning than ExpZ from an oenological point of view.

Influence of the freezing method on the changes that occur in grape samples after frozen storage

BACKGROUND Sample freezing is frequently used in oenological laboratories as a compromise solution to increase the number of samples that can be analysed, despite the fact that some grape characteristics are known to change after frozen storage. However, freezing is usually performed using standard freezers, which provide a slow freezing. The aim of this work was to evaluate whether blast freezing would decrease the impact of standard freezing on grape composition. RESULTS Grape quality parameters were assessed in fresh and in frozen stored samples that had been frozen using three different procedures: standard freezing and blast freezing using either a blast freezer or an ultra-freezer. The implications of frozen storage in grape samples reported in earlier research were observed for the three freezing methods evaluated. Although blast freezing improved repeatability for the most problematic parameters (tartaric acidity, TarA; total phenolics, TP), the improvement was not important from a practical point of view. However, TarA and TP were relatively repeatable among the three freezing procedures, which suggests that freezing had an effect on these parameters independently of the method used . According to our results, the salification potential of the must is probably implied in the changes observed for TarA, whereas for TP the precipitation of protoanthocyanins after association with cell wall material is hypothesized to cause the lack of repeatability between fresh and frozen grapes. CONCLUSIONS Blast freezing would not imply a great improvement if implemented in oenological laboratories, at least for the parameters included in this study.

Allometric relationships for estimating vegetative and reproductive biomass in grapevine (Vitis vinifera L.)

Background and Aims Vineyards, one of the most widespread agricultural systems, have significant but scarcely evaluated carbon sequestration potential. Allometry is a cost-effective approach to estimate plant biomass, but few studies – focused mainly on permanent structure carbon fixation – have dealt with it in grapevine. This study develops allometric models that accurately estimate grapevine standing biomass (total vine biomass at harvest), using extensive field-collected data sets. Methods and Results Data were obtained in vineyards located in Spanish regions representative of the variability found in warm semi-arid Mediterranean regions. We developed and validated functions to estimate vine biomass for all vine organs. The models obtained estimated accurately the biomass fixed by each organ separately and even more accurately at the whole plant scale. To illustrate the potential of the models, they satisfactorily assessed the influence of seasonal vine water status on vine biomass production and partitioning using an independent data set. Conclusions and Significance of the Study The models constitute a powerful tool to determine in a non-destructive and cost-effective manner standing biomass from simple vine measurements, which makes them suitable for quantifying carbon stocks and allocation patterns, and for evaluating the influence of climate or cultural practices at large scale to estimate better – at a regional or international level – the contribution of grapevine culture to CO2 balances.

Prediction of spatial variability of water status in a rain fed vineyard in Spain

Monitoring water status at different points within a single field is time-consuming and expensive. Nevertheless, it is necessary to consider within-field variability since water status is usually highly variable and has a large effect on grape quality. To overcome this situation, models that allow estimation of the relative difference in vine water status between a reference point and other points in the field have been developed. The aim of this work is to evaluate the performance of a model developed in South Eastern France for the spatial prediction of vine water status to the conditions of a traditional rain-fed vineyard in Rioja Alavesa, Spain. The model proved to be suitable to estimate grapevine water status variability within a medium size vineyard (4.2 ha) under the traditional growing conditions in Rioja Alavesa (gobelet trained cv. Tempranillo vines with no irrigation), although it was necessary to include some water status related information (in this case carbon isotope ratio (δ13C) from the previous season) to improve the performance and applicability of the model.

Development of a standardized methodology for phenotypical characterizations in apple

4 Pags.- 2 Tabls. Articles derived from XIV EUCARPIA Symposium on Fruit Breeding and Genetics (Bologna,Italy. June 14-18 2015) . The definitive version is available at: http://www.actahort.org/index.htm