Response of some morphological traits, grain yield and nitrogen efficiency of safflower genotypes by Azotobacter chroococcum and nitrogen fertilizer under rainfed conditions

This study was performed for the evaluation of the effect of Azotobacter and nitrogen levels on morphological traits, plant nitrogen uptake rate, seed oil and yield and nitrogen use efficiency of six safflower (Carthamus tinctorius L.) genotypes under rainfed conditions, as a factorial experiment based on a randomized complete block design with three replications, during 2015-2016 and 2016-2017 growing seasons. Experimental factors were seed inoculation with Azotobacter and urea chemical fertilizer application (Non-inoculated with Azotobacter and urea as control, seed inoculation with Azotobacter, inoculation with Azotobacter + 50% N and inoculation with Azotobacter + 100% N) and six genotypes of safflower (312-S6-692, PI-401478, PI-253895, PI-306974, padide and sina). The combined analysis of variance for two years showed that the main effects of fertilizer and genotype had significant effect on all of the traits. The interaction of nitrogen × genotype was significant on root volume, leaf are index, number of lateral branches, grain nitrogen, straw nitrogen and total nitrogen uptake. Result showed that inoculation with aztobacter + 50% use of nitrogen had higher nitrogen use efficiency than aztobacter + 100% use of nitrogen. However, there was no significant difference in the grain yield between those fertilizer treatments. Sina with the highest values of grain yield (1203 kg.ha-1) and nitrogen use efficiency (17.49 kg.kg) was considered as superior variety. Therefore, with the aim of reducing environmental pollution by excessive use of N chemical fertilizer, application of Azotobacter is suitable for safflower production under daryland conditions.