Relative Salt Tolerance of 18 Chili Pepper Cultivars

Salt tolerance of 18 chili pepper cultivars (16 Capsicum annuum cultivars and two Capsicum frutescens cultivars) was conducted in a greenhouse experiment. Seedlings were grown in 4-inch pots filled with Metro-mix 360 commercial substrates. During the one-month experimental period (August 12 to September 12, 2013), seedlings were treated with nutrient solution (control) at electrical conductivity (EC) of 1.1 dS·m^-1 or saline solution at EC of 5.0 dS·m^-1 (salt treatment) for a total of seven times. All chili pepper plants did not experience any visible foliar salt damage (leaf edge burn, necrosis, or discoloration). However, salt treatment significantly decreased plant growth with large variations among cultivars. Plant height, leaf area, and shoot dry weight of 18 chili pepper cultivars reduced by 7-34%, 17-47%, and 13-39%, respectively. Hierarchical cluster analysis was conducted based on multivariate parameters including relative plant height, leaf area, and shoot dry weight. All chili pepper cultivars were clustered into three groups . Capsicum annuum ‘Keystone Resistant Giant’ and ‘New Mexico 6-4’ were the most tolerant cultivars to salinity. Capsicum annuum ‘Charleston Hot’, ‘Golden Bell’, ‘Hungarian Yellow Wax’, ‘Mesilla Cayenne’, ‘Mirasol’, ‘NuMex Centennial’, ‘NuMex Española Improved’, and Capsicum frutescens Malagueta’ had intermediate salt tolerance, whereas Capsicum annuum ‘Barker's Hot’, ‘California Wonder’, ‘Cayenne’, ‘Pimiento’, ‘Rio Grande’, ‘Sandia’, ‘Sonora’, and Capsicum frutescens ‘Tabasco’ were the most sensitive cultivars to salinity.