Response of two greenhouse pepper hybrids to NaCl salinity during different growth stages

The salt tolerance of two greenhouse bell-pepper hybrids (Capsicum annuum L., 'Sonar' and 'Lamuyo') was studied during germination, seedling growth and vegetative growth in hydroponic culture. Salinity treatments were imposed by irrigating with half-strength Hoagland solution containing 0, 10, 25, 50, 100 and 150 mM/1 of NaCl. Salinities up to 50 mM delayed germination but did not reduce the final germination percentage. It was reduced significantly at 100 and 150 mM NaCl in both hybrids. Seedling growth was reduced significantly with salinities higher than 10 mM NaCl. Plant growth parameters such as plant height, total leaf area and dry weight were significantly (P=0.05) reduced at salinities higher than 25 mM NaCl in both hybrids. Roots had the highest Na+ concentration compared to leaves, which increased with increasing salinity, while Cl- in leaves was much higher than Na+. Potassium concentration of plant tissues was less affected than Na and Cl by salinity increase. Total fruit yield in both hybrids was significantly reduced at salinities higher than 10 mM NaCl, the reduction being 95% at 150 mM NaCl. Both, fruit number per plant and fruit weight were reduced by the salinity. Our results suggest that during the growth stages studied, the hybrid 'Lamuyo' is more sensitive to salinity than the hybrid 'Sonar'. (C) 2000 Elsevier Science B.V. All rights reserved.