Effect of sowing date on the contents of protein and saponin and grain yield of different quinoa genotypes in Jiroft

Due to drought, water crisis and increasing soil salinity in Jiroft region in recent years, it seems necessary to cultivate alternative crops for the cold season with low water requirements, high economic efficiency and compatibility with the region and short growth period. Quinoa (Chenopodium quinoa Willd.) is a good choice for this due to its low water requirement and high salinity resistance. Therefore, this study aimed to investigate the protein and saponin contents as well as yield and yield components of quinoa genotypes during autumn and winter cultivation.

This experiment was performed as a split plot in the form of a randomized complete block design with 4 replications, in the research farm and laboratory of the Agricultural Research and Training Center and Natural Resources in the south of Kerman province in the two cropping years of 2018-2019. Planting date (autumn and winter) was the main factor and the genotypes Titicaca, Redcarina, Gza1, Q12, Q18, Q21, Q22, Q26, Q29, Q31 were the second factors. In this experiment, traits such as stem length, the length of growth period, seed protein and saponin contents, 1000-seed weight and grain yield were determined.

Combined analysis of variance of the data showed that the traits measured in this experiment (stem length, length of growth period, percentage of seed protein and saponin) were significantly affected by genotype, planting date and their interactions. Inflorescence length was only significantly affected by genotype. Stem length was very different in autumn and winter cultivation so that in autumn cultivation the highest stem length occurred in Q22 and Q12 genotypes but in winter cultivation the highest stem length was related to Q26 and Q29 genotypes. In all studied genotypes, the percentage of saponin and protein in autumn cultivation was less than winter cultivation, the range of changes in grain saponin and protein percentage was between 4.52 to 5.56 and 10.78-13.89 percent, respectively. Also, grain yield and 1000-seed weight of quinoa were significantly affected by genotype, planting date and their interactions. The range of grain yield changes varied between 1.91 (autumn cultivation treatment and GZA1 genotype) to 3.99 tons per hectare (autumn cultivation treatment Q12).

The results of this study also showed that it is possible to cultivate this crop twice a year in Jiroft region, provided that appropriate cultivars are used. Therefore, Q12 and Q31 cultivars are recommended for autumn cultivation while Q29 and Q26 cultivars are recommended for winter cultivation.