Eco-physiological evaluation of ‘Vairo’ cultivar grafted onto different rootstocks

Abstract

Almond (Prunus dulcis) is the most important nut crop in terms of world production. New almond cultivars and rootstocks have been created to satisfy world increasing demand, consumption trends and new agronomic production models. The aim of this study was to understand the influence of eight different Prunus rootstocks on the behaviour of almond cultivar ‘Vairo’. The study was carried out in an experimental orchard of IRTA located in Les Borges Blanques, Catalonia. The trees were planted in 2010 and the data used in this study were collected during the summer of 2017. The rootstocks evaluated were: ‘GF-677’, ‘ISHTARA’, ‘IRTA 1’, ‘IRTA 2, ‘ROOTPACR’, ‘ROOTPAC-40’, ‘ROOTPAC-20’ and ‘Puebla de Soto’. Periodic measurements were carried out. Leaf chlorophyll concentration, quantum yield of PSII, shoot growth, stem water potential, stomatal conductance, canopy volume, photosynthetically active radiation, fruit volume, fruit weight and yield were the parameters analysed. A statistical analysis was made and showed significant differences between rootstocks. ‘Vairo’ cultivar seemed to be best adapted to the ‘GF-677’ rootstock. This combination was also the best suited to the site conditions, having the healthier trees, producing bigger and heavier fruits and with the highest yield. Regarding tree water status, ‘Vairo’ cultivar grafted onto ‘ROOTPAC-40’ presented the less stressed trees. Moreover, when grafted onto ‘ROOTPAC-20’ rootstock, ‘Vairo’ cultivar presented the smallest fruits, smallest kernels, lowest fruits weights, lowest kernels weights and lowest yield, making it the less suitable combination. For a healthier and productive orchard, the right rootstock choice is one of the most important factors to consider. However, choosing a rootstock only by its main characteristics and discarding its adaptability to the soil and climate may not be the best approach.