## 2 Material and Methods  
### Field Conditions, Plant Materials, and Irrigation Treatments  
All of the trials and experiments were carried out in a plot of 0.12 ha of adult Monastrell variety trellis wines in an experimental orchard located in Cehegin (Murcia) (38\({}^{\circ}\)6\({}^{\prime}\)38.13\({}^{\prime\prime}\) N, 1\({}^{\circ}\)40\({}^{\prime}\)50.41\({}^{\prime\prime}\) W, 432 m a. s. l.) during years 2018-2021. Grapevines (_Vitis vinifera_ L., var. Monastrell, syn. Mourvedre) were 20+ years old, and the Monastrell clones studied are 4, 94, 188, 276, 360, 372, and 373, grafted on rootstock 110R. These traditional clones were recovered from a prospection made in old vineyards in the Region of Murcia, SE Spain, in the 2000s. Planting density was 3 m between rows and 1 m between plants (3333 vines/ha). The soil of the plot is clayey (>40% clay, 36%-38 silt) and has an organic-matter content between 0.82-1.05%, a pH of 7.40, an electrical conductivity of 0.13 dS m\({}^{-1}\), an active limestone (CaCO\({}_{3}\)) between 17-19%, a cation exchange capacity of 18 meq/100 g, a C/N ratio between 7.1-8.1, a total N between 0.067-0.078%, and an assimilable P between 10.7-14.7 mg/kg. The irrigation water that was used came from a well and had a pH of 7.96 and an electrical conductivity of 0.68-0.81 dS m\({}^{-1}\). Climate is Mediterranean semi-arid, with hot and dry summers and a scarce annual rainfall (Table 1). The training system was a bilateral cordon trellised to a three-wire vertical system (Figure 1). The vine rows ran NW-SE. Six two-bud spurs (12 nodes) were left after pruning, while in May, green non-productive shoots were removed from each vine in the same manner for all of the treatments, according to the grower's practice in the area. \begin{table}
\begin{tabular}{c c c c c c c c c} \hline \hline
**Phenological Period** & **Period of the Year** & **Eto (mm)** & **VPD (kPa)** & **Rain-Fall** & **T\({}^{*}\)max** & **T\({}^{*}\)med** & **T\({}^{*}\)min** & **Solar Rad.** \\ \hline Year 2018 & & & & & & & & \\ Budburst-fruit set & 15 April-14 June & 265 & 0.98 & 78 & 23.7 & 16.7 & 8.8 & 268 \\ Fruit set-version & 15 June-31 July & 291 & 2.00 & 0.1 & 32.8 & 24.6 & 14.4 & 328 \\ Version-harvest & 1 August-20 September & 219 & 1.39 & 57 & 31.0 & 23.76 & 16.43 & 229 \\ Postharvest & 21 September-31 October & 97 & 0.77 & 26.8 & 23.8 & 16.5 & 9.93 & 165 \\ Dormney period & 1 November-14 April & 289 & 0.52 & 126.3 & 17.03 & 8.3 & 0.60 & 147 \\
**Total/annual average** & **1161** & **1.13** & **288.2** & **25.67** & **19.97** & **10.03** & **227** \\ Year 2019 & & & & & & & & \\ \hline \hline \end{tabular}
\end{table} 
Table 1: Mean values of several climatic parameters in different phenologial periods for every year of the experiment in the study area. Crop evapotranspiration (ETc = Eto \(\times\) Kc) was estimated using varying crop coefficients (Kc)--based on those proposed by the FAO, adjusted for the Mediterranean area-- and reference evapotranspiration (ETo) values (Table 1). The applied Kc values were 0.35 in April, 0.45 in May, 0.52 in June, 0.75 in July--mid August, 0.60 in mid-August-early September, and 0.45 in mid-September--October. The ETo was calculated weekly from the mean values of the preceding 12-15 years, using the Penman Monteith-FAO method and the daily climatic data collected in the meteorological station (Campbell mod. CR 10X) located at the experimental vineyard and belonging to the Servicio de Informacion Agraria de Murcia (SIAM, IMIDA). Each clone was irrigated from April to October using high-frequency drip irrigation (2-5 times per week during the late evening, depending on the phenological period), applying an optimized regulated deficit irrigation (RDI) strategy throughout the year (Control treatment) and a severe deficit irrigation strategy where no irrigation was applied