Univrsity of Tehran Press Iranian Journal of Field Crop Science 2008-4811 52 2 2021 06 22 Qualitative and quantitative yields of different spring rapeseed (Brassica napus) genotypes in response to sowing season and date in Karaj region Qualitative and quantitative yields of different spring rapeseed (Brassica napus) genotypes in response to sowing season and date in Karaj region 173 184 84232 10.22059/ijfcs.2020.301743.654715 FA Taraneh Samarzadeh Vazhdehfar Ph.D. Candidate, Department of Agronomy, Faculty and Agriculture and Natural Resources, Islamic Azad University, Karaj branch, Iran. Farzad Paknejad Department of Agronomy, Faculty and Agriculture and Natural Resources, Islamic Azad University, Karaj branch, Iran. 0000-0003-0951-2072 Amir Hossein Shirani Rad Seed and Plant Improvement Institute (SPII), Agricultural Research, Education and Extension Organization (AREEO), Karaj, Iran. Mostafa Oveisi Department of Agronomy and Plant Breeding, Faculty and Agriculture and Natural Resources, University of Tehran, Karaj, Iran. 0000-0003-0742-5485 Saeed Vazan Department of Agronomy, Faculty and Agriculture and Natural Resources, Islamic Azad University, Karaj branch, Iran. Journal Article 2020 04 28 Due to having spring and autumn genotypes and adaptation to weather conditions, rapeseed is considered as a point hope to provide edible oil of country. Two separate experiments were set up as split-plot in a RCBD design with three replications in two fall and winter seasons during two years (2014-2015 and 2015-2016) at the research field of Seed and Plant Improvement Institute to investigate the effect of sowing season and date on the quantitative and qualitative yields of rapeseed genotypes in Karaj, Iran. In this study, the main plots were sowing dates (7, 17, and 27 October in fall sowing and 9 and 19 February, and 1 March in winter sowings) and sub-plots consisted of genotypes (RGS003, Dalgan, Zabol10, Hyola401, and Hyola4815). Rapeseed genotypes grain and oil yields were 4330 and 1840 kg ha-1 in fall sowing, respectively, while these traits were decreased 43.3 and 46.6% respectively, when rapeseed genotypes were planted in winter season. The highest grain and oil yields (5033 and 2202 kg ha-1) belonged to 7 October sowing date in fall sowing, while 9 February had the highest grain and oil yields (2996 and 1248 kg ha-1) in winter sowing. In general, the Dalgan genotype is recommended for cultivation due to suitable agronomic traits such as number of silique per plant, number of grain per silique, silique length, 1000-grain weight, as well as high grain and oil yields in cold temperate regions with arid and semi-arid climates such as Karaj, Iran. Due to having spring and autumn genotypes and adaptation to weather conditions, rapeseed is considered as a point hope to provide edible oil of country. Two separate experiments were set up as split-plot in a RCBD design with three replications in two fall and winter seasons during two years (2014-2015 and 2015-2016) at the research field of Seed and Plant Improvement Institute to investigate the effect of sowing season and date on the quantitative and qualitative yields of rapeseed genotypes in Karaj, Iran. In this study, the main plots were sowing dates (7, 17, and 27 October in fall sowing and 9 and 19 February, and 1 March in winter sowings) and sub-plots consisted of genotypes (RGS003, Dalgan, Zabol10, Hyola401, and Hyola4815). Rapeseed genotypes grain and oil yields were 4330 and 1840 kg ha-1 in fall sowing, respectively, while these traits were decreased 43.3 and 46.6% respectively, when rapeseed genotypes were planted in winter season. The highest grain and oil yields (5033 and 2202 kg ha-1) belonged to 7 October sowing date in fall sowing, while 9 February had the highest grain and oil yields (2996 and 1248 kg ha-1) in winter sowing. In general, the Dalgan genotype is recommended for cultivation due to suitable agronomic traits such as number of silique per plant, number of grain per silique, silique length, 1000-grain weight, as well as high grain and oil yields in cold temperate regions with arid and semi-arid climates such as Karaj, Iran. https://ijfcs.ut.ac.ir/article_84232_78d4ca251e7fbf3ed003e5a73ac56fbc.pdf