Effect of sowing date and plant density on seed yield and yield attributes of quinoa (Chenopodium quinoa) genotypes

Quinoa (Chenopodium quinoa) is world-renowned for its nutritional and health benefits and its adaptability to different environments. Despite some research on quinoa cultivation, determining the appropriate planting date and density for different genotypes and regions needs to be studied. The main objective of this study was to determine the effects of planting date and planting density on quinoa seed yield in climatic conditions of Kermanshah. In this regard, field experiments were conducted during two growing seasons (۲۰۱۹-۲۰۲۰) at the research farm of Razi University, Kermanshah, Iran. The experiments were conducted as split-plot factorial in randomized complete blocks design with three replications. Three sowing dates (March ۱۵th, April ۱۵th, and May ۱۵th) were assigned to the main plots, two planting densities (۴۰ and ۶۰ plants m-۲), and three genotypes including Titicaca, Q۲۹, and Red Carina as subplots. The results showed that the highest seed yield (۲۱۷۹.۷۲ and ۲۲۶۷.۳۹ kg ha-۱) were achieved on April ۱۵th, ۲۰۱۹ and May ۱۵th, ۲۰۲۰, respectively. Sowing dates of April ۱۵th in ۲۰۱۹ and May ۱۵th in ۲۰۲۰ with a plant density of ۶۰ plants m-۲ and Titicaca genotype had the highest seed yield for quinoa in Kermanshah climatic conditions. The results showed that panicle length and biological yield had a positive and significant correlation with grain yield in all studied planting dates. There was a positive and significant correlation between grain yield and grain weight per plant, ۱۰۰۰-grain weight, and biological yield at both densities. The path analysis revealed that panicle length had the highest positive direct effect on seed yield followed by ۱۰۰۰-seed weight on the first sowing date in ۲۰۱۹ and ۲۰۲۰, while biological yield and panicle length had the highest positive direct effect on seed yield on the second and third sowing dates, respectively. This experiment showed that genotypes and planting dates are the most determining factors affecting quinoa growth, development, and yield compared with planting densities. 

Keywords:

Agronomic traits , correlation , path analysis , Temperate climate