Relative Salt Tolerance of Twenty-Four Chili Pepper Cultivars

A greenhouse experiment was conducted to screen 24 chili pepper cultivars (23 Capsicum annuum cultivars and one Capsicum frutescens cultivar) for salt tolerance. Seedlings were grown in 4-inch pots containing Metro-mix 360 commercial substrates. During the one-month experimental period (June 28 to July 29, 2013), seedlings were treated with nutrient solution at electrical conductivity (EC) of 1.1 dS·m^-1 (control) or saline solution at EC of 5.0 dS·m^-1 (salt treatment) for a total of seven times. No visible foliar salt damage (leaf edge burn, necrosis, or discoloration) was observed on any chili pepper plants. However, salt treatment significantly reduced plant growth with large variations among cultivars. Plant height, leaf area, and shoot dry weight of 24 chili pepper cultivars decreased by 17-40%, 20-58%, and 23-51%, respectively. Cluster analysis was conducted using multivariate parameters including relative plant height, leaf area, and shoot dry weight. All chili pepper cultivars were classified into three groups. Capsicum annuum ‘El Rey Jalapeño’, ‘Guajillo’, ‘NuMex Big Jim’, ‘NuMex Conquistador’, and Capsicum frutescens ‘Greenleaf Tabasco’ were the most salt tolerant. Capsicum annuum ‘Carolina Cayenne’, ‘Cayenne Thick’, ‘El Jefe Jalapeño’, ‘NMCA 10652’, ‘NuMex Eclipse’, ‘NuMex R. Naky’,  ‘NuMex Sunglo’, ‘Santa Fe Grande’, ‘Santaka’, and ‘Tam Veracruz’ had intermediate salt tolerance, whereas Capsicum annuum ‘Ancho’, ‘Ancho Mulato’, ‘Arizona’, ‘De Árbol’, ‘Early Jalapeño’, ‘NuMex Joe E. Parker’, ‘NuMex Sunburst’, , ‘NuMex Sunflare’, and ‘Sweet Banana’ were salt sensitive.