Effect of Sowing Date on Yield, Yield-Companent and Grain Protein of Different Quinoa (Chenopodium quinoa Willd.) Genotypes in Jiroft Weather Conditions

Abstract
Quinoa is an annual plant belonging to the Amaranthaceae family with high adaptability and acceptable yield in different environments. In order to determine the most suitable planting date and quinoa genotype, a split plot experiment was conducted in a randomized complete block design with three replications in the research farm of university of Jiroft in 2018-2019 season year. Sowing date in three levels August 23, September 11 and October 2 were as main plots and quinoa genotypes in ten levels Red Carina, Titicaca, Giza1, Q₁₂, Q₁₈, Q₂₁, Q₂₂, Q₂₆, Q₂₉ and Q₃₁ were as sub plots. The results showed the highest plant height (122.9 cm), number of panicles per plant (18), number of spikes per panicle (12.1), biomass yield (9760 kg.ha^-1), seed yield (4243.3 kg.ha^-1) and protein yield (374.3 kg.ha^-1) was related to Q₁₂ variety on the first sowing date. However, Q₂₆ and Q₂₉ genotypes were not significantly different from Q12 genotype in most of the investigated traits. In general, the planting date of September 1 is the best planting date and the Q₁₂, Q₂₆ and Q₂₉ genotypes are recommended for Jiroft region, due to the higher yield and better growth characteristics, it can be recommended on the first of September under the same conditions as this research, although it is necessary to repeat the research for more definitive results.
Introduction
Quinoa belongs to the Taj Khorosian family, it is an annual plant, dicotyledonous, self-growing, broad-leaved, one to two meters high, and has a deep root system (Jacobsen et al., 2003). Ecologically, quinoa is a plant resistant to acidic soil conditions, drought, frost (Valencia-Camuro, 2004), hot and dry weather. Sowing date due to the change in temperature, day length, temperature, and relative humidity has a significant effect on the growth and development of the plant during the growing season and is one of the most important management factors affecting the production of crops (Khichar and Niwas, 2006). The autumn sowing date of quinoa varies from September to late November. In general, according to different climates and temperature during planting and harvesting, the date of planting can be determined for each region (Bagheri, 2017). This study was conducted with the aim of investigating the history of different cultivations in different cultivars and genotypes of quinoa in the subtropical region of Jiroft.
Material and Methods
In order to determine the most suitable planting date and quinoa genotype, a split plot experiment was conducted in a randomized complete block design with three replications in the research farm of university of Jiroft in 2018-2019 season year. Sowing date in three levels August 23, September 11 and October 2 were as main plots and quinoa genotypes in ten levels Red Carina, Titicaca, Giza1, Q₁₂, Q₁₈, Q₂₁, Q₂₂, Q₂₆, Q₂₉ and Q₃₁ were as sub plots. Quinoa seeds were cultivated manually with a distance between rows of 50 cm and a distance between plants of 5 cm (Bagheri, 2017). A drip irrigation system was used for irrigation.The origin of genotypes Q12, Q18, Q19, Q21, Q22, Q26, Q27, Q29, Q31 is Chile, Red Carina of Egypt and Titicaca of Denmark (Bazile et al., 2016). The genotypes used in this research were obtained from the Research and Education Center for Agriculture and Natural Resources in the south of Kerman province, located in Jiroft city. At the end of the growing season, yield traits and yield components were measured per unit area after removing the margin effect. Seed protein concentration was measured by modified Bradford method (Lorin and Matolis, 2005). Data were analyzed using SAS software and means were compared using the least significant difference (Dancan) at the 5% level.
Results and discussion
The results showed the highest plant height (122.9 cm), number of panicles per plant (18), number of spikes per panicle (12.1), biomass yield (9760 kg.ha^-1), seed yield (4243.3 kg.ha^-1) and protein yield (374.3 kg.ha^-1) was related to Q₁₂ variety on the first sowing date. However, Q₂₆ and Q₂₉ genotypes were not significantly different from Q12 genotype in most of the investigated traits. Delay in planting date caused a significant decrease in seed yield. Comparison of the average effect of planting date on seed yield showed that the highest seed yield was obtained from the first and second planting dates with an average of 3,397.6 and 3,163 kg.ha^-1, respectively, and the lowest was from the third planting date with an average of 2,093.3 kg.ha^-1. Parger et al. (2018) observed the highest seed yield among the studied quinoa genotypes in the Zeno genotype with 2430 kg. Seed yield had a positive and significant correlation with plant height, stem diameter, number of panicles per plant, number of spikelets per panicle. The results of protein yield showed that genotype Q12 had the highest protein yield with 585.9 kg.ha^-1 and Red Carina and Titicaca cultivars (224.1 and 193.6 kg.ha^-1) had the lowest protein yield. The amount of quinoa seed protein is a function of the improvement of traits such as the number of panicles per plant, the weight of 1000 seeds, the harvest index and the biomass weight, which occurs following suitable temperature conditions with different phenological stages of the plant.
Conclusion
In general, the planting date of September 1 is the best planting date and the Q₁₂, Q₂₆ and Q₂₉ genotypes are recommended for Jiroft region, due to the higher yield and better growth characteristics, it can be recommended on the first of September under the same conditions as this research, although it is necessary to repeat the research for more definitive results.