Desarrollo de estrategias de riego deficitario controlado y selección del portainjerto para mejorar la calidad y funcionalidad de los pistachos (pistacia vera)

Resumo

ABSTRACT The need to accelerate the use of water in agrosystems is a fact assumed by farmers and regulatory councils. This irreversible situation forces us to live with the scarcity of water resources and develop reliable tools to guarantee the competitiveness of fruticulture. However, most of the deficit irrigation strategies are not based on concrete water deficit levels in the plants, nor it is clear whether it implies an improvement of the functional and sensory characteristics of the fruits. In this sense, the existing literature is scarce and contradictory, mainly due to the fact that: (i) in certain publications there is a lack of precision in defining the hydric state of the crop studied (duration of stress, speed of imposition of the same, etc.) and (ii) the existence of a linear relationship between the water deficit and the accumulation of bioactive compounds is assumed. The main hypothesis of this Thesis is that there is no linear relationship between the level of bioactive compounds of the fruits and level of water stress (controlled); while under high water stress there is an important stomatal regulation and CO2 is used to maintain the primary metabolism, under a moderate deficit, CO2 is redistributed to the formation of secondary metabolites to the detriment of growth. This situation results in products with a higher content of bioactive compounds in those fruits in which the water deficit has been controlled. In addition, situations of water stress cause an accumulation of antioxidant substances, as a physiological response to the elimination of free radicals formed. Therefore, it is believed that through the precise management of water deficit levels it is feasible to achieve minimal production losses and in turn generate top quality products. These products, as a result of an optimization of water use and having a high quality, will have a marked identity that will differentiate them from the rest of their category, facilitating their inclusion in more demanding international markets. Under these premises, the concept of “hydroSOStainable products” was developed and applied to pistachio farming and commercialization, demonstrating that consumers positively value healthy products, those that respect the environment and those that have good functional properties, even willing to pay up to 10 % more for this type of products. Once the concept was developed and put into practice, a study of the quality of pistachios from eight cultivars was carried out, to perform a complete characterization of the obtained nuts. Once the one that, under the studied criteria, was considered as that having the best quality (cultivar Kerman), was chosen, a combined study of different treatments of controlled deficit irrigation and rootstocks was carried out to study their influence on the physical, chemical, functional and sensory quality of the pistachios obtained. It was shown that a soft regulated deficit irrigation treatment, applied during the phenological phase II of pistachio cultivation, is capable of causing an improvement in the physical, functional, chemical and sensory quality of the affected fruits, unaltered the antimutagenic and cytotoxic properties that their compounds have against cancer cells. The use of the P. terebinthus rootstock during pistachio cultivation led to fruits of higher quality (morphological, texture, fatty acids, antioxidant capacity and polyphenol content) than those produced using P. atlantica and P. integerrima rootstocks. This fact represents an unquestionable advance for fruticulture, because it allows farmers to obtain products of higher quality and with a clear added value when perceived as sustainable and environmentally friendly products.