TOXICITY SYMPTOMS AND TOLERANCE OF STRAWBERRY TO SALINITY IN THE IRRIGATION WATER

Symptom characteristics and tolerance to different types of salinity i n the irrigation water on strawberry (Fragaria x ananassa Duch.) culti vars was studied in soil pot experiments, The responses of the cultiva rs 'Douglas' and 'Toro' were compared when they were irrigated with wa ter containing either 0, 6, 12, 18 or 24 meq l(-1) NaCl or with water containing either 0, 6, 12, 18 or 24 meg l(-1) NaHCO3. In another expe riment, the cultivar 'Douglas' was irrigated with water containing eit her 0, 6, 12 or 18 meq l(-1) NaCl; 0, 6, 12 or 18 meq l(-1) KCl, or 0, 6, 12 or 18 meq l(-1) Na2SO4. The overall results indicate that Na2SO 4 and NaHCO3 do not provoke immediate harmful effects on strawberry wh ereas the chlorinated waters (NaCl and KCl) cause phytotoxicity. Thus the leaf scorch is basically due to the increase in the foliar Cl- con centration. The hydric stress derived from the electrical conductivity of tile saturated soil extract (EC,) is an adverse factor which contr ibutes to the development of lesions on the leaves. When considering t he incidence and evolution of leaf scorch, 'Toro' is more tolerant to salinity. II can be calculated that if the leaf Cl- concentration is l ess than 1% and the EC less than 2 dS m(-1), no toxic symptoms are pro duced in the leaves of the cultivars of strawberry under study. (C) 19 97 Elsevier Science B.V.