In vitro tissue culture as a tool for Croatian grapevine germplasm management

La región de Abruzzo está situada entre los Apeninos y el mar Adriático, limitando al norte con el río Tronto y al sur con el Trigno. Desde un punto de vista físico se divide en dos franjas

The climate is the environmental factor that contributes with greater weight in the variability of the yield and the composition of the grape, therefore, it is key in the determination of the typicity of the product. Of the environmental factors, the evolution of water availability conditions, among other things, the biochemical evolution of the compounds of the grape and the type of wine to be elaborated. An integrating parameter of the hydric state of the plant is the carbon isotopic composition (δ13C). This indicator is a useful parameter to characterize the water status during the maturation period and estimate the transpiration efficiency or water use efficiency (EUA) in the vine.

Terroir is a complex concept which associates soil, climate, grape variety and cultural practices that include the training system and oenological techniques. It is a type of social construction with man at its centre. The typicality of a wine is also a social construction which is the result of an agreement among specialists vis à vis a given quality of the wine whose references are the wine’s origins (e.g. terroir) and taste.

This experiment tries to characterize the role of soil, climate and harvest date on the composition of grape-derivated thiols, 3-mercapto-hexanol (3MH) and 3-mercapto-hexile acetate (A3MH), in the white wines from Colombard varieties in Gascony (South-West of France). A network of 6 plots has been observed since 1999 on different pedologic units. The plots have common agronomical characteristics, plantation spacing (2,900 to 3,500 vines per ha), plantation aging (1985-1990), strength conferred by rootstock (SO4, RSB), soil management (grass covered 1 by 2) and training system (vertical shoot positionning pruned in single Guyot). Meteorological stations are located near the plots.

Root system architecture (RSA) is important for soil exploration and edaphic resources acquisition by the plant, and thus contributes largely to its productivity and adaptation to environmental stresses, particularly soil water deficit. In grafted grapevine, while the degree of drought tolerance induced by the rootstock has been well documented in the vineyard, information about the underlying physiological processes, particularly at the root level, is scarce, due to the inherent difficulties in observing large root systems in situ. The objectives of this study were to determine genetic differences in the root architectural traits and their relationships to water uptake in two Vitis rootstocks genotypes (RGM, 140Ru) differing in their adaptation to drought. Young rootstocks grafted upon the Riesling variety were transplanted into cylindrical tubes and in 2D rhizotrons under two conditions, well watered and moderate water stress. Root traits were analyzed by digital imaging and the amount of transpired water was measured gravimetrically twice a week. Root phenotyping after 30 days reveal substantial variation in RSA traits between genotypes despite similar total root mass; the drought-tolerant 140Ru showed higher root length density in the deep layer, while the drought-sensitive RGM was characterised by shallow-angled root system development with more basal roots and a larger proportion of fine roots in the upper half of the tube. Water deficit affected canopy size and shoot mass to a greater extent than root development and architectural-related traits for both 140Ru and RGM, suggesting vertical distribution of roots was controlled by genotype rather than plasticity to soil water regime. The deeper root system of 140Ru as compared to RGM correlated with greater daily water uptake and sustained stomata opening under water-limited conditions but had little effect on above-ground growth. Our results highlight that grapevine rootstocks have constitutively distinct RSA phenotypes and that, in the context of climate change, those that develop an extensive root network at depth may provide a desirable advantage to the plant in coping with reduced water resources.