Planting dates and irrigation regimes influence on growth and yield of quinoa (Chenopodium quinoa) in a semi-arid area

Planting crops with less vulnerability to environmental stresses, especially drought in semi-arid areas, can remarkably improve irrigation water use efficiency (IWUE). Therefore, in this study, planting quinoa (Chenopodium quinoa) under different irrigation regimes and planting dates was investigated. Irrigation regimes included full irrigation (FI) and 50% of full irrigation (0.5FI), where planting dates consisted of six planting dates in the early spring and six planting dates in the early fall. Results indicated that the highest grain yield, dry matter, root dry weight, leaf area index, harvest index, and yield components were obtained in early spring cultivation on February 19 and in the early fall on August 23 planting dates. The maximum leaf area index on the planting date of August 23 was 21% higher than that on the planting date of February 19 under FI conditions. The highest harvest index was 0.32 in FI and the planting date of August 23. The planting date of August 23 increased water use efficiency for grain (IWUEG) by 30% compared to planting on February 19 under FI conditions. There was no significant difference in specific root length between planting dates on February 19 and August 23. Applying 0.5FI compared to FI increased root dry weight to shoot dry weight ratio to 142% on the planting date of August 23. Generally, the planting date of August 23 is suggested as the best planting time for quinoa in the study area with no water scarcity, while planting on February 19 is recommended in the conditions of scarce water resources by applying 0.5FI.