Evaluation Physiological Parameters of Canola (Brassica napus L.) Affected Different Concentration and Stage of Use Gibberellic acid under Warm and Dry Climate Condition (Southwest of Iran)

BACKGROUND: Growth regulators play an essential role in the biosynthesis of crop fibres, affecting both the elongation rate and quality. Gibberellic acid (GA3) is a phytohormone that is needed in small quantities at low concentration to accelerate plant growth and development. OBJECTIVES: Current study was done to assess response of grain yield, its components, morphological and qualitative traits of canola genotypes to apply different time and concentration of growth regulator hormone (gibberellic acid). METHODS: This research was done via combined analysis split plot factorial experiment based on randomized complete blocks design with three replications. The main factor included different level of canola genotypes (Hyola401, RGS003, Jerry) and sub factors consisted different concentration of gibberellic acid (0, 50 and 100 mg.l-1) and several time of application of gibberellic hormone (at before planting grain treatment, vegetative phase before flowering, flowering before pod emergence). RESULT: According result of analysis of variance effect of genotype, different concentration and time of application of gibberellic hormone on all measured traits (instead Chlorophyll) was significant at 5% probability level but interaction effect of treatments was not significant. The highest and lowest amount of all measured traits between genotypes was for Hyola 401 and Jerry, respectively. Assess mean comparison result of application different concentration of gibberellic hormone indicated the maximum amount of number of pod per plant (97.31), number of grain per pod (18.71), 1000-grain weight (2.89 gr), grain yield (2575 kg.ha-1), Biological yield (7620 kg.ha-1), harvest index (33.79%), oil content (46.42%), oil yield (1192.51 kg.ha-1), Catalase enzyme (21.65 unit/mg protein) and Peroxidase enzyme (17.89 unit.mg protein-1) were noted for 100 ppm gibberellic and minimum amount of those traits belonged to control. Compare different time of application of gibberellic hormone revealed the highest and lowest amount of all measured traits (instead protein content and protein yield) were for vegetative phase before flowering stage and Flowering before pod emergence, respectively. CONCLUSION: According result of current study advised to use Hyola401 hybrid with 100 ppm gibberellic hormone at VPBF growth stage to achieve maximum crop production by farmers.