Effects of Water Quality and Irrigation Management on Growth and Yield of Quinoa

In this study, six irrigation treatments including well water (1.23 dS.m-1; control treatment), saline water (15 dS.m-1), alternate saline water and freshwater, mixture of 50:50 saline and freshwater (7.2 dS.m-1), subsurface irrigation with saline water (15 dS.m-1), and subsurface irrigation with well water (1.23 dS.m-1) were evaluated on some growth parameters, yield, and biochemical characteristics of Quinoa (CV. Titicaca). The research was done based on completely randomized design including 3 replications as pot planting in the Ferdowsi University of Mashhad, in greenhouse conditions, during 2017-2018. The results showed that the effect of different irrigation regimes on total soluble carbohydrate in leaf and stem, root fresh weight, and root length was significant at 1 percent level (P<0.01), while the leaf and stem fresh weight were significant at 5 percent level (P<0.05). Subsurface irrigation with saline water decreased leaf, stem, root fresh weight; grain yield, 1000 kernel weights, total soluble carbohydrate in leaf and stem by about 14%, 12.1%, 47.9%, 6.5%, and 5.6 %, respectively. Also, total soluble carbohydrate in leaf and stem increased by about 55.3% and 70.09 %, respectively. The alternate irrigation treatment decreased leaf, stem, root fresh weight, grain yield, and 1000 kernel weight by 22.8%, 23.7%, 34.1%, 8.1%, and 7.7%, respectively. Irrigation with saline water (15 dS.m-1) during all of the growth stages decreased grain yield and 1000 kernel weights by 20.8% and 20.0 %, respectively. In this research, sub-surface irrigation treatment with freshwater was the optimum treatment with the highest yield. Thus, if saline water is used, alternate irrigation treatment is recommended.