terclim by ICS banner
IVES 9 IVES Conference Series 9 GiESCO 9 Comparing different vineyard sampling densities and patterns for spatial interpolation of intrinsic water use efficiency

Comparing different vineyard sampling densities and patterns for spatial interpolation of intrinsic water use efficiency

Abstract

Context and purpose of the study – The need to rationalize agricultural inputs has recently increased interest in assessing vineyard variability in order to implement variable rate input applications, so-called ‘precision viticulture’. In many viticultural areas globally, precision viticulture is already widely used such as for selective harvesting and variable rate application (VRA) of inputs such as irrigation and/or fertilizer. Robust VRA relies on having a geostatistically accurate map (of one or more vineyard attributes) requiring high sampling densities, which can be cost- and time-prohibitive to obtain. Previous work on spatial interpolation using kriging have upscaled ground-based measurements, but such upscaling strategies are applicable only when vineyard conditions are spatially continuous and satisfies the assumption of second-order stationary processes. Alternatively, mixed models that combine kriging and auxiliary information, such as the regression kriging (RK) method, are more instructive for spatial predictions. In order to improve prediction accuracies, it is therefore necessary to incorporate additional information to achieve accurate spatial patterns with low error. Here, we used a hybrid approach where information derived from multiple sources – point (ground-based) and high resolution remote sensing (aerial, continuous) – was used to spatially interpolate leaf-level intrinsic water use efficiency (WUEi) in a South Australian Shiraz vineyard to improve the prediction accuracy and lower the error estimates of WUEi.

Material and methods – We utilised a upscaling approach where aerial imagery was used to improve the accuracy of spatially-interpolated ground-based measurements to obtain a reliable geostatistical (kriging) model with respect to error rates. We also compared different sampling densities and distributions; gridded vs. stratified sampling distribuitions were compared viz. upscaling UAV images in order to obtain a geostatistically accurate estimate of WUEi. Relationships between UAV altitude and number of ground sampling points were obtained vs. kriging error rates. To the best of our knowledge, this is the first study reporting on the spatial prediction of WUEi from multiple data sources.

Results – The integration of UAV images with ground data of WUEi effectively improved the spatial accuracy of WUEi through the RK technique. We found that kriging WUEi  based on stratified sampling had a lower interpolation error compared to gridded sampling. We found that gridded sampling error rates increased more rapidly with increasing flight altitude (or higher ground spatial distance) than stratified sampling. Our findings could help viticulturists to rapidly develop highly accurate spatial maps of vine performance parameters.

DOI:

Publication date: July 5, 2023

Issue: GiESCO 2023

Type: Poster

Authors

Alessandro MATAFFO1, Boris BASILE1, Vinay PAGAY2*

1Department of Agricultural Sciences, University of Naples Federico II, Viale Italia, 83100 Avellino, Italy
2School of Agriculture, Food & Wine, The University of Adelaide, PMB 1, Glen Osmond, SA 5064, Australia

Contact the author*

Keywords

grapevine, kriging, water use efficiency, UAV, geostatistics, sampling distribution

Tags

GiESCO | GIESCO 2023 | IVES Conference Series

Citation

Related articles…

Tomatoes and Grapes: berry fruits with a (bright) biotech future?

Tomatoes and Grapes are berries that are genetically related and therefore at least partially their developmental pathways leading to a fleshy fruit should share some of the components. In a sense knowledge obtained from the model plant tomato could be useful for grape and conversely the more amenable tomato can be used to test some hypothesis that would be difficult to obtain in grape. Research in my lab and other labs have led to a better understanding of the molecular genetics mechanisms underlying fruit development and ripening in tomato and more specifically those related to metabolite accumulation that may lead to changes in fruit nutritional and flavor composition. This research has involved the use of genetic variability in natural population, but also biparental population and genetically engineered lines that are easy to develop in tomato tomato but not in grape. NGTs also can be easily implemented in tomato to not only speed up the gene-to-trait but also develop new tomato varieties.

Methodological advances in relating deep root activity to whole vine physiology

Full understanding of grapevine responses to variable soil resources requires
assessing the grapevine root system. Grapevine root systems are expansive and examining deep roots (i.e., >40 cm)
is particularly important in conditions where grapevines increase reliance on deep soil resources, such as drought
or plant competition. Traditional methods of assessing roots rely on morphological traits associated specific
functions (e.g., root color, diameter, length), while recent methodological advances allow for estimating root
function more directly (e.g., omics). Yet, the potential of applying refined methods remains underexplored for roots
at deep depths.

NACs intra-family hierarchical transcriptional regulatory network orchestrating grape berry ripening

Considering that global warming is changing berry ripening timing and progression, uncovering the molecular mechanisms and identifying key regulators governing berry ripening could provide important tools in maintaining high quality grapes and wine. NAC (NAM/ATAF/CUC) transcription factors represent an interesting family due to their key role in the developmental processes control, such as fruit-ripening-associated genes expression, and in the regulation of multiple stress responses. Between the 74 NAC family members, we selected 12 of them as putative regulators of berry ripening: NAC01, NAC03, NAC05, NAC11, NAC13, NAC17, NAC18, NAC26, NAC33, NAC37, NAC60 and NAC61.

Molecular characterization of a variegated grapevine mutant cv Bruce’s Sport

Variegation, a frequently observed trait in plants, is characterized by the occurrence of white or discoloured plant tissue. This phenomenon is attributed to genetic mosaicism or chimerism, potentially impacting the epidermal (L1) and subepidermal (L2) cell layers. In grapevine, variegation manifests as white or paler leaf, flower, or berry tissues, often leading to stunted growth and impeded development. Despite its prevalence, variegation in grapevines remains understudied.

Phenotypical impact of a floral somatic mutation in the cultivar Listán Prieto

The accession Criolla Chica Nº2 (CCN2) is catalogued as a floral mutation of cultivar Criolla Chica (synonym for cv. Listán Prieto). Contrary to what is observed in hermaphrodite-cultivated varieties like Criolla Chica, CCN2 exhibits a prevalence of masculinized flowers. Aiming to study the incidence and phenotypical implications of this mutation, CCN2 plants were deeply studied using Criolla Chica ‘Ballista’ (CCBA) as control plants. For each CCN2 plant, two inflorescences per shoot were sampled and segmented into proximal, mid and distal positions, relative to the pedicel. Flowers were observed through magnifying lens and classified according to OIV151 descriptor.