Introducing Fall Planting Date of Cold Tolerant Oilseed Rape (Brassica napus L.) Genotypes for East Azarbaijan Climate

The present research was done in order to determine the suitable fall planting date of oilseed rape in the East Azarbaijan climate (cold and semi-arid with freezing winters in Copen climate classification system),to evaluate of late planting effects on cold damage, seed and oil yields, yield components and to introduce cold tolerant genotypes. The experiment was conducted as split plotbased on RCBD design with two factorsincluding sowing date with 3 levels (11 and 21 September and 1 October) and 14 fall oilseed rape genotype in three replications. The study was carried out in East Azarbaijan Agriculture and Natural ResourcesResearch and Education Center during two years (2014-15 and 2015-16). The results indicated that plants in the 11 September planting date had significantly higher values of pods per plant, seeds in the pod, 1000 seeds weight, seed and oil yields. Late sowing datesdecreased seed and oil yields by decreasing yield components and increasing cold damage in oilseed rape genotypes.Therefore, 11 September could be a suitable dateforthe cultivation fall genotypes of oilseed rape in East Azarbaijan and areas with similar climate.Correlations among the seed and oil yields with cold damage percent and yield components were significantly negative and positive respectively. It seems that yield decrease in late planting dates can occur via omiting plants from farm and decreasing yield components. L55, HL2012, Wpn-6, L72, SW102, HL3721genotypes indicated higher seed and oil yields in fall cultivations and are suitable for cultivation in East Azarbaijan.