Soil salinization is a global concern, especially in arid and semiarid regions with large and growing populations. It is becoming even more intense because high-quality irrigation water is limited and alternative water sources such as municipal reclaimed water are encouraged to be used for irrigating landscapes in some areas in the southwestern United States and northern Mexico. The irrigation of croplands with alternative waters has resulted in the accumulation of salts in soil and groundwater (Rozema and Flowers, 2008). The degree of soil salinization depends on the quality of irrigation water, soil property, fertilizer application, and rainfall because these factors influence the soil moisture content, cation exchange capacity, and transportation of water.
Salinity influences plant growth and development in all stages, although the degree of the negative salinity effect may be growth stage-dependent. For most crops, plants are generally more tolerant during germination but become more sensitive during emergence and early seedling growth stages (Maas, 1986; Rhoades, 1999). Once established, plants generally become increasingly tolerant during later growth stages. High salinity also induces a series of metabolic dysfunctions in plants, including absorption of excessive minerals, nutrient imbalance, and inhibition of photosynthesis (Azza Mazher et al., 2007; Marschner, 2002; Munns and Tester, 2008). The degree of the negative effect of salinity on plant growth and physiological processes depends on salinity level and length of exposure. The actual response of a plant to salinity is often affected by climate conditions, type of substrate or soil, and irrigation management in addition to growth or developmental stage.
Ornamental chile peppers (Capsicum annuum) are popular bedding plants and containerized plants resulting from their compact growth habit and numerous fruits that spread over the top of the plant and attractive foliage (Coon et al., 2008). The indeterminate growth habit produces fruits in all stages of development and provides an elegant blend of colors throughout the summer and fall (Stommel and Bosland, 2005). For example, the chile fruit starts green and then changes from ivory to red with bullet-shaped pods for ‘NuMex Valentine’s Day’, from ivory to orange with more rounded pod for ‘NuMex St. Patrick’s Day’, and from ivory to lemon yellow with a round pod for ‘NuMex Memorial Day’. However, information on the response of ornamental chile peppers to irrigation water with elevated salts is limited. Recent studies have showed that ornamental chile pepper ‘Black Pearl’ and ‘Calico’ were moderately salt-tolerant and may be irrigated with saline water up to 4.0 dS·m−1 with little reduction in aesthetical appearance (Niu et al., 2010a). Also, a large variation in salt tolerance exists among chile pepper cultivars (Niu, 2012; Niu et al., 2010b, 2010c). The purpose of this study was to determine the relative salt tolerance of 10 cultivars of ornamental chile peppers based on seedling emergence, visual quality, growth, and physiological responses when germinated and irrigated with saline solution at elevated salinity levels.
Arrowsmith, S., Egan, T.P., Meekins, J.F., Powers, D. & Metcalfe, M. 2012 Effects of salt stress on capsaicin content, growth, and fluorescence in a Jalapeño cultivar of Capsicum annuum (Solanaceae) BIOS 83 1 7
Azza Mazher, A.M., Fatama El-Quesni, E.M. & Farahat, M.M. 2007 Responses of ornamental plants and woody tress to salinity World Journal of Agricultural Sciences 3 386 395
Coon, D., Votava, E. & Bosland, P.W. 2008 The chile cultivars of New Mexico State University. Agricultural Experiment Station. Bul. 763
Dutt, S.K., Bal, A.R. & Bandyopadhyay, A.K. 1991 Salinity induced chemical changes in Casuarina equistifolia Forst Egyptian Journal of Soil Science 31 57 63
Flynn, R., Phillips, R., Ulery, A., Kochevar, R., Liess, L. & Villa, M. 2002 Chile seed germination as affected by temperature and salinity. Cooperative Extension Service, New Mexico State University, Las Cruces, NM
Fox, L.J., Grose, J.N., Appleton, B.L. & Donohue, S.J. 2005 Evaluation of treated effluent as an irrigation source for landscape plants J. Environ. Hort. 23 174 178
Gavlak, R.G., Horneck, D.A. & Miller, R.O. 1994 Plant, soil, and water reference methods for the western region. Western Regional Extension Publication (WREP) 125
Helmke, P.A. & Sparks, D.L. 1996 Lithium, sodium, potassium, rubidium, and cesium. In: Sparks, D.L. (ed.). Methods of soil analysis, Part 3, chemical methods. 5th series. Soil Science Society of America and American Society of Agronomy, Madison, WI
Kumar, V., Shriram, V., Nikam, T.D., Jawali, N. & Shitole, M.G. 2008 Sodium chloride-induced changes in mineral nutrients and proline accumulation in indica rice cultivars differing in salt tolerance J. Plant Nutr. 31 1999 2017
Marschner, H. 2002 Mineral nutrition of higher plants. 2nd Ed. Elsevier Academic Press, London, UK
Niu, G. 2012 Salt tolerance of Capsicum species and genotypes, p. 150–164. In: Russo, V.M. (ed.). Peppers, botany, production and uses. CAB International, Wallingford, UK
Niu, G., Rodriguez, D.S., Call, E., Bosland, P.W., Ulery, A. & Acosta, E. 2010b Responses of eight chile peppers to saline water irrigation Sci. Hort. 126 215 222
Niu, G., Rodriguez, D.S., Cabrera, R., Jifon, J., Leskovar, D. & Crosby, K. 2010c Salinity and soil type effects on emergence and growth of pepper seedlings HortScience 45 1265 1269
Rhoades, J.D. 1999 Use of saline drainage water for irrigation, Agronomy Monograph No. 38. p. 615–657
Siddiqi, E.H. & Ashraf, M. 2008 Can leaf water relation parameters be used as selection criteria for salt tolerance in safflower (Carthamus tinctorius L) Pak. J. Bot. 40 221 228
Stommel, J.R. & Bosland, P.W. 2005 Ornamental pepper, Capsicum annuum, p. 555–593. In: Anderson, N.O. (ed.). Flower breeding & genetics: Issues, challenges, and opportunities for the 21st century. Kluwer Academic Publishers, The Netherlands
Tabatabai, M.A. & Frankenberger, W.T. Jr 1996 Liquid chromatography, p. 225–247. In: Sparks, D.L. (ed.). Methods of soil analysis, Part 3, chemical methods. 5th series. Soil Science Society of America and American Society of Agronomy, Madison, WI
Van Zandt, P.A., Tobler, M.A., Mouton, E., Hasenstein, K.H. & Mopper, S. 2003 Positive and negative consequences of salinity stress for the growth and reproduction of the clonal plant, Iris hexagona J. Ecol. 91 837 846
Zhani, K., Elouer, M.A., Aloui, H. & Hannachi, C. 2012 Selection of a salt tolerant Tunisian cultivar of chile pepper (Capsicum frutescens) EurAsian Journal of Bioscience 6 47 59