5. Dr. Maria Mar Alsina Marti

In California the grape industry is one of the major agriculture drivers, and currently 70% (250000 ha) of the grape acreage are planted to wine grapes. Regulating vine water status along the growing season is crucial to achieve the desired yields and quality. Too much stress at certain phenological stages result in yield losses that may carry over to the next season, while at other stages, the water deficit is purposely caused to regulate vegetative and/or grape growth and improve quality. Long periods of drought and frequent heat waves are becoming more common in California, and these events are likely to increase in length and severity.  Therefore, viticulturists need tools to minimize irrigation while avoiding excessive stress and maintain profitable yields. Remote sensing techniques can provide spatial information of vine water status over large vineyard areas compared with the more traditional methods that are time consuming and only provide discrete information. However, the proposed remote sensing methodologies often require very high-resolution images, not routinely available and costly. Publicly available thermal and optical data from satellites may not have the spatial resolution required for complex vineyard canopy architecture In the GRAPEX project; we have collected vine water status data under different spatial resolution thermal and optical images with the aim to develop water status models that can be used in a commercial environment. Here we present a summary of our results, and we review the achievements along with the unresolved issues.