Accelerating fall growth and improving the yield of rapeseed (Brassica napus L.) via Trichoderma fungi treatment for delaying planting time in cold climates

The goals of the study were to consider the possibility of delaying planting time of fall safflower from 11 September to 11 October in cold climates via increasing rosette plants growth for suitable cold tolerance and enhancing seed yield by using trichoderma fungi.

Methods and Materials:

 An experiment was conducted as split plot based on a randomized complete blocks design with three replications in the Khosrowshah station of East Azarbaijan Agriculture and Natural Resources Research and Education Center during the 2021-22 cropping season. The experimental factors included planting time (11 and 21 September and 1 and 11 October), and trichoderma fungi (Trichoderma harzianum) treatment included control, soil and seed treatments. The Ahmadi as a fall rapeseed genotype was used during the study.

Delaying the planting time from 11 September to 11 October led to diminishing leaf chlorophyll concentration, plant growth rate and increasing plant cold damage percentage and a significant decrease in seed and oil yields and seed yield components. The treatment of the soil and seed with trichoderma fungi increased the mentioned yield related traits, but these increases were significantly higher in seed treatment plots. The mean of the seed yield increased by 1005 and 613 Kg h-1 in 11 September and 11 December planting times respectively in the case of treating seeds by trichoderma fungi.

The rapeseed treatment with trichoderma fungi increased rosette plants growth, decreased cold damage percentage and increased seed yield significantly in early and late season cultivations at cold climate.