RESPONSE OF BLACKBERRY (Rubus spp.) CV. TUPY TO SALINITY

Blackberry (Rubus spp.) is a crop of socioeconomic importance in Mexico, and its fruits have high nutritional value. However, there is little information on the effect of salinity on this crop, so this research focused on the impact of salinity on growth, yield, proline content in the root, and fruit quality of blackberry cv. Tupy. Plants were sowed in 19 L pots with tezontle (red volcanic rock) (2 to 3 mm) and were watered with a nutrient solution using an open hydroponic system. The treatments were saline nutrient solutions with electrical conductivities (CE) of 2.0 (control), 2.2, 2.4, 2.6, 2.8, and 3.0 dS m(-1), applied daily from 45 weeks after transplant until fruiting. Yield, plant dry weight, diameter of the cane, number of fruits, total chlorophyll concentration, and carotenoids content were reduced by 60, 30, 24, 54, 50 and 46 %, respectively, and the concentration of proline in the root increased by 122 % with 3.0 dS m(-1). Conductivities from 2.6 to 3.0 dS caused a decrease in weight, length, and diameter of the fruit by 16, 11, and 6.9 %, respectively. The roundness index was 6 % lower with 3.0 dS, and only the 2.8 dS m(-1) conductivity increased fruit firmness by 11 %. The remaining treatments and control had statistically similar values. With 3.0 dS m(-1), total soluble sugars of the fruit decreased by 50 %, titratable acidity and total soluble solids increased by 22 % and 8 %, the concentration of phenols and flavonoids was 25 and 29 % lower, while the antioxidant capacity and the inhibition percentage were 21 and 18 % higher respectively. The anthocyanin concentration was 95 % higher, with conductivities of 2.2 to 2.8 dS.