Effect of Chitosan on Growth, Yield and Certain Salinity Stress-Related Metabolites in Two Barley Cultivars Contrasting in Salt Tolerance تأثیر الکیتوزان على النمو، المحصول و بعض المحتویات البیوکیماویة ذات العلاقة بالاجهاد الملحى فى صنفین من الشعیر یتمایزان فى قدرتهما على تحمل الملوحة

The present study aimed to elucidate the effect of chitosan on germination, growth, yield and certain salinity stress-related metabolites in two barley cultivars contrasting in salt tolerance namely cvs. Giza 129 (salt susceptible) and Giza 136 (salt tolerant). Salinity stress treatments were commenced 30 days after sowing via soil irrigation with either NaCl or CaCl2 each at three levels 0, 3000 mgL-1 (4.6875 dS m-1) and 6000 mgL-1 (9.375 dS m-1). The obtained results indicated that both types of salinity at 6000 mgL-1 decreased germination percentage, growth parameters, total chlorophylls, relative water content and yield whereas increased mean germination time as well as carotenoids, proline and total soluble sugars (TSS). Chitosan (CHS) treatment at 200 mgL-1 increased yield and its components in plants growing under normal conditions, and alleviated the negative effects of salinity on characters that were negatively-affected in salinity-stressed plants. On the other hand, there was an additive effect between salinity and CHS on inducing the content of carotenoids, proline and TSS. The damaging effect of salinity was more pronounced in case of NaCl compared with CaCl2, and the alleviative effects of CHS was more pronounced at 200 mgL-1. Salinity tolerance of cv G 136 may be attributed to higher seed germination potential along with higher intrinsic contents from proline and TSS.