Abstract

BACKGROUND: Charcoal rot of strawberry (Macrophomina phaseolina) is an emerging disease difficult to manage, a desirable alternative is the use of resistant cultivars. However, little is known regarding the reaction of cultivars to the pathogen under water stress conditions. OBJECTIVE: The aims of this work were to study the effect of water stress on the physiology of four strawberry cultivars during the infection, and to determine the relationship between water stress and cultivar susceptibility. METHODS: Healthy and inoculated plants of 'Monterey', 'Albion', 'Camarosa' and 'Sabrina' were maintained under no irrigation and full irrigation regimes, in greenhouse conditions. Stem water potential (SWP) and stomatal conductance (gs) were evaluated. The disease severity was recorded weekly for seven weeks. RESULTS: The disease detrimentally affected the water relations in 'Sabrina', 'Albion' and 'Monterey'. A significant correlation was detected between the evaluated parameters and the disease severity. The disease severity increases in plants with no irrigation, regardless of cultivar. CONCLUSIONS: Our results show that the infection caused by M. phaseolina increases the negative effects of water stress, depending on the genotype, and that the cultivars that were able to maintain more stable water relations respond better to the disease.