The effect of sowing date and planting density on grain yield and some nutritional quality characteristics of three seed-quinoa genotypes

Quinoa (Chenopodium quinoa Willd) is a plant with high nutritional value and has good adaptability to different growing conditions. To investigate the effects of planting date and density on the seed quality of three quinoa genotypes (Q۲۹, Titicaca, and Red Carina), a field experiment was conducted in ۲۰۱۹-۲۰۲۰ at the research field of Agriculture and Natural Resources Campus, Razi University, Kermanshah, Iran. The seeds were sown on three dates (۱۵th March, ۱۵th April, and ۱۵th May) under two planting densities (۴۰ and ۶۰ plants/m۲). The experiment was conducted as a split-plot factorial design based on the randomized complete block design with three replications. The results revealed that both sowing date and plant density influenced the nutritional composition of the quinoa genotypes. The grain yield varied between ۱۶۴۲ and ۲۳۵۱ kg/ha, and the amino acids profile varied according to planting date and planting density. The amino acids histidine, glutamic acid, leucine, and lysine increased with delaying sowing date whereas threonine, tyrosine, arginine, methionine, glycine, proline, isoleucine, valine, serine, alanine, aspartic acid, asparagine, cysteine, phenylalanine, and glutamine decreased with delaying the sowing date from ۱۵ March to ۱۵ May. The Titicaca genotype produced maximum grain yield under the third sowing date while in the case of the first sowing date, all studied genotypes were more responsive regarding most amino acids. Also, the most suitable plant density to result in the highest grain yield was ۶۰ plants/m۲. The mineral content of the quinoa seeds was not influenced significantly by the sowing date, plant density, genotype, and their interactions, except for calcium which was affected significantly by the genotype. The lowest saponin content was observed in Titicaca under the planting density of ۴۰ plants/m۲. These results indicated that both sowing dates and plant densities influence the nutritional composition of quinoa genotypes.

Keywords:

Cultivar , Grain Yield , minerals , Nutritional Value , Protein