Improvement and regeneration of canola seeds (Brassica napus) with growth promoting compounds under different irrigation intervals

The use of growth promoting compounds is one of the possible ways to improve and restore seed quality. This study was conducted as a split plot experiment in a randomized complete block design with three replications in 2019. The main plots consisted of three irrigation intervals (irrigation at 40, 60 and 80% of available moisture depletion) and the subplots was different growth promoting compounds in six levels consisted of control, soil application of humic acid and foliar spray of amino acid, fulvic acid, seaweed extract and the combination of growth stimulants. Results showed that irrigation regime of 80% available moisture depletion decreased germination rate and seed vigor by 11.0% and 28.01% compared to 40% depletion respectively. Increase of irrigation intervals also increased seed electrical conductivity. At the irrigation level of 80% moisture depletion, maximum germination with the means of 87% and 85% was observed in the combination of growth stimulants and spray of amino acids respectively. Growth stimulants improved seedling dry weight. Under irrigation conditions of 60 and 80% moisture depletion, the combination of growth stimulants increased the alpha-amylase activity by 31.03 and 71.42% respectively. On the whole, considering the positive effects of growth promoting compounds on improving and regenerating the seeds of canola they can be recommended in drought stress conditions.