Differences in Growth and Water Use Efficiency in Four Almond Varieties Grafted onto Rootpac-20

Abstract

Almond cultivation in the Mediterranean area has undergone important changes leading to the current trend of intensification. In this scenario, low-vigor rootstocks have recently been developed, such as the ‘Rootpac®’ series, but knowledge about the rootstock’s influence on adaptation to high-density planting systems is very scarce. The objective of this work was to assess the morphological and physiological response of four almond cultivars grafted on ‘Rootpac-20’. To this end, one-year-old almond plants (Prunus dulcis (Mill) D. A. Webb.) cv ‘Penta’ (P), ‘Guara’ (G), ‘Vialfas’ (V) and ‘Soleta’ (S) were grown in pots, irrigated at field capacity (from June to September). Plant height and trunk diameter were measured periodically, and the water use efficiency of production was determined at the end of the trial. Evapotranspiration was measured throughout the experiment. The trunk diameter was greater in S and G at the end of the trial. Similarly, the tallest plants were G while the shortest ones were P. In general, G and S had a higher water use efficiency than V and P. ‘Soleta’ grafted on ‘Rootpac-20’ had higher evapotranspiration values (+25%), which is an important issue when selecting plant material, especially in the case of limited water availability for irrigation.