Investigation of agronomic traits of spring rapeseed (Brassica napus L.) cultivars in response to the winter planting dates by use of zinc application

To increase the quantitative yield of canola (Brassica napus L.),due to the interaction of zinc application in winter planting dates on spring canola cultivars.

The experiment was performed as a factorial split-plot in a randomized complete block design with three replications was conducted during two experimental years (2016-2017) in Alborz province (Karaj).Experimental factors including winter planting date in three levels (11.20, 11.30 and 12.10) and zinc factor in two levels (no application of zinc and application of zinc in stem elongation stage were considered as factorial in the main plots and factor cultivars were classified into four levels (Sarigol, Dalgan, Salsa and Solar) in the subplot.

The results showed that planting date has a great impact on yield, yield components and oil of canola cultivars.Delayed culture reduced leaf chlorophyll concentration.Also the yield components of canola were reduced due to delay in planting and non-application of zinc,which eventually reduced the yield of canola seed and oil.The tested genotypes had the highest yield on the date of normal cultivation.The highest oil yield was observed in the Dalgan cultivar (2066 kg/ha) due to zinc application on normal cultivation.Delay in planting caused an increase in glucosinolate.

In general, foliar application of zinc,reduced the negative effects of delay in planting in most of the studied traits of different rapeseed cultivars.Due to the effect of zinc application and adaptation of Dalgan cultivar to a certain range of planting date for canola production in this area and areas with similar climates is recommended