Salt tolerance of ‘Hass’ avocado grafted onto the West Indian ‘Nachar’ rootstock

Abstract

Aim of the study: The nowadays avocado cropping world burst confronts water quality constraints as it unfolds throughout semi-arid climates. Therefore, many salt-tolerant rootstocks have been developed, with those from the West Indian avocado subspecies such as ‘Nachar’ standing out. However, the salt-tolerance of ‘Nachar’ had not been characterized and this study fills this knowledge gap. Area of study: Accordingly, an open-air trial was performed in Moncada (València). Material and methods: ‘Nachar’ seedling rootstocks grafted with ‘Hass’ avocado were irrigated with five nutritive solutions differing in chloride (Cl^-), but with low sodium (Na⁺) adsorption ratio (SAR). Plant development and leaf nutrient status, including Cl^- and Na⁺, were monitored, and the ‘Nachar’ salt-tolerance was characterized based on the accumulation rates of leaf Cl^- and Na⁺ as a function of, respectively, Cl^- and SAR in the irrigation water. These parameters are seldom expressly assessed but are argued here as providing better insight into the actual Cl^- and Na⁺ exclusion ability of rootstocks than the usual maximum permissible, —to avoid leaf injury— leaf Cl^- and Na⁺. Main results: The ‘Nachar’ was found to rank high and very high in, respectively, Cl^- and Na⁺ exclusion ability, when compared to other avocado rootstocks. However, more salt-driven leaf injuries and potential yield losses would still be expected in avocado grafted onto the ‘Nachar’ in comparison to other salt-sensitive woody crops. Research highlights: The ‘Nachar’ seems an interesting starting point in further rootstock improvement for salt-tolerance in avocado. However, if unproperly carried out, the propagation of salt-tolerant avocado rootstocks such as ‘Nachar’ and others may also result in the loss of the previously achievements of salt-tolerance.