Genetic Variation for Salt Tolerance in European Sweet and Bitter Quinoa and Their Offspring

Quinoa has a high salt tolerance, however, mainly bitter quinoa varieties have been tested. We tested the salt tolerance of European sweet varieties (Atlas, a selection from Riobamba, Pasto and Jessie versus a bitter dark seed Red Carina) in a pot trials at 0 to 400 mM NaCl (EC of 0 to 40 dS/m).

In the pot trial, analysis of grain yield and of relative biomass growth rate (RGR) and its components (RGR=SLA*LWR*NAR) showed that all sweet European varieties were more salt tolerant than a control barley variety. Grain yields per plant at 300 mM NaCl were still over 30 % of the grain yield at 0 mM NaCl. Under crop conditions higher plant densities might fully compensate for this smaller plant size. The selection from Riobamba performed best with highest absolute grain production per plant and with still over 38 % at 300 mM NaCl of the grain yield at 0 mM.

Both RGR analysis and small scale analysis of light interception versus biomass and grain production showed that photosynthesic efficiency was 20 % lower at 300 mM than at 0 mM NaCl (for 'net assimilation rate' (NAR) in the RGR analysis and 'radiation use efficiency' (RUE) in the light interception analysis). Also, the conversion of leaf mass to leaf area is negatively effected (SLA is lower at high EC). A field trial at very high salt levels > 50 dS/m showed genetic variation in a mapping population for survival time at high salt for which QTL were found.