Salinity Tolerance of Four Lowland Varieties of Quinoa (Chenopodium quinoa Willd.): Responses to Three Levels of NaCl and Na2SO4 Under Two Fertilization Levels.

Soil salinization poses a growing threat to agriculture worldwide. Growing halophytic crops like quinoa (Chenopodium quinoa) is one potential solution to this problem. Quinoa is a pseudograin from South America and one of the most salt tolerant crops known. Little data exists on salinity tolerance within the Chilean lowland quinoa ecotype which is best adapted to temperate latitudes. This greenhouse experiment aimed to characterize the salinity tolerance within the lowland ecotype.

Two runs of the experiment were conducted, with three replications per run and three subsamples for each treatment combination. A single plant in a six-inch, 3 L pot constituted a subsample. Treatments consisted of seven salinity levels (no-salt control and 8, 16, and 32 dS/m for NaCl and Na2SO4), two fertilization levels (1 g N, 0.66 g P2O5, 0.35 g K2O; 3 g N, 1.97 g P2O5, 1.04 g K2O), and four varieties. Height measurements were taken 70 dap. SPAD measurements, which measure plant health via chlorophyll, were taken 73 dap. Once processed, yield and salt uptake into plant tissue will be analyzed. The barley cultivar “Albacete” was included as a frame of reference and its yield will be analyzed.

Highly significant effects were seen on SPAD by variety (p<.0001), salinity (p<.0001), and fertilizer (p<.0001). Significant interactions between fertilization and variety (p=.0177) and between salinity and fertilization (p=.0035) were seen for plant height. SPAD measurements were all significantly different for the three Chilean varieties and were positively correlated with northern location of origin within Chile. The no-salt control had the highest SPAD value. For NaCl, SPAD value decreased significantly with each increase in concentration and for levels of Na2SO4, there were no statistically significant differences. High fertilization had a significantly detrimental effect, causing reduced germination and stunting.