Salinity tolerance and nitrogen use efficiency of quinoa for expanded production in temperate North America

Adam Joshua Peterson

Quinoa has attracted increasing attention worldwide and in North America due to its high level of mineral nutrition and superior tolerance to marginal agriculture conditions and abiotic stresses. A wide range of challenges and opportunities currently face expanded quinoa production in North America. Heat susceptibility, pre-harvest sprouting, and downy mildew are among the most important of these challenges. In spite of these challenges, varieties with tolerance to high temperatures and resistance to pre-harvest sprouting and downy mildew have been identified. Quinoa’s high level of salinity tolerance will also allow the crop to take advantage of marginal agriculture conditions that limit productivity of other crops. Two experiments were conducted to explore quinoa’s potential for expanded production in North America. The first experiment examined the relative salinity tolerance of four Chilean lowland varieties to determine their suitability for cultivation on saline soils in North America. All quinoa varieties were grown at 8, 16, and 32 dS m-1 NaCl and Na2SO4 and at a no-salt control. Quinoa demonstrated high levels of salinity tolerance, far exceeding that of barley, a crop generally considered saline tolerant. Additionally, variation for salinity tolerance was found among the four quinoa varieties. On the basis of yield, quinoa was found to better tolerate Na2SO4 than NaCl at equal EC levels. Previous studies on quinoa and other crops indicate that salinity can significantly impact mineral nutrition of seeds. Our results indicate complex but significant effects from salinity, fertilization level, and variety, and the interaction of these factors, on Ca, Cu, Fe, Mg, Mn, P, and Zn concentrations in quinoa seed. The second experiment investigated the response of a wide range of varieties to four levels of a nitrogen-rich organic fertilizer. However, large declines in yield due to high temperatures limited the recovery of useful data on nitrogen use efficiency from the study. Valuable data was gathered on the relative levels of heat tolerance present among the Chilean lowland cultivars currently part of the WSU quinoa program. Field observations indicate that natural selection in 2011 may have increased heat tolerance in the same varieties grown the following year.

Salinity tolerance and nitrogen use efficiency of quinoa for expanded production in temperate North America

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