Evaluation of yield and yield components of some rapeseed cultivars with endophyte P. indica and A. siccitolerans under drought stress

One of the global and national problems for the production of agricultural products is drought stress that the encounter with at least one of the important stages of the plant life cycle. Therefore, the development of drought-resistant cultivars and more food production from less water in a situation where the development of agricultural land is not possible, has led to more attention to increase yield per unit area.. Therefore, according to the country's need to increase oilseed production, this study was aimed to investigate the evaluate the yield and yield components of inoculation of different rapeseed cultivars with mycorrhiza-like fungi (Piriformosporaindica) and growth-promoting bacterium (Arthrobactersiccitolerans) on growth, yield and yield components of canola under normal and water stressed conditions.

This experimentwas performed to investigate the effect of inoculation of 10 different cultivars of rapeseed cultivars with mycorrhiza-like fungus (Piriformospora indica) and growth-promoting bacterium (Arthrobacter siccitolerans) on growth, yield and quantitative and qualitative yield components of rapeseed under drought stress in field conditions at the Agricultural Research Center of MohagheghArdabili University located on 10 km from Ardabil, in the form of split-split plots based on a randomized complete block design with three repetitions in 2016-17 and 2017-2018. Experimental treatments included two levels of irrigation as the main factor, normal irrigation and drought stress in podding stage and three levels of microbial inoculation (without inoculation, P.indica inoculation and A.siccitolerans inoculation as a sub-factor and 10 cultivars of winter rapeseed (Karaj 1, Karaj 2, Karaj 3, Talayeh, Zarfam, Licord, SLM-046, Modena, Opera, Okapi) as a sub-factor totally consists of 60 treatments.

The results showed that irrigation cut off, significantly reduced grain yield, biological yield, leaf area index, number of seeds per pod, pod length, pod per plant, 1000-seed weight and plant height. The results of comparing the mean interactions of drought stress and genotype showed that the highest grain and biological yields related to Talayeh genotype with 3323.5 and 9745 kg/ha yield under drought stress conditions, respectively, and also the highest 1000-grain weight related to Opera genotype by weight. It was 4.9gr. The highest decrease in grain yield as a result of drought stress was related to Karaj-2 genotype with a decrease of 693.2 and the decrease in biological yield was related to Modena genotype with a decrease of 2004.3 kg/ha and 1000-grain weight loss was related to Zarfam genotype with a decrease of 1.39gr. Was. In contrast, the highest increase in grain yield due to inoculation of seeds with P.indica and A. siccitolerans, related to the Okapi genotype with an increase of 332.08 and 436.25 kg/ha, respectively, and the highest increase in biological yield related to the Modena genotype with an increase 1239.41 was under inoculation with A. siccitolerans and an increase of 1205.58 was under inoculation with P.indica. In general, drought stress reduced grain yield and biological yield by 24 and 20.5%, respectively, but inoculation with P.indica and A.siccitolerans improved grain yield under drought stress conditions by 7 and 10, respectively. Percentage and improvement of biological yield were 12.6% and 11%, respectively. Also, under conditions of drought stress, inoculation of seeds with P.indica and A.siccitolerans improved grain yield by 10.5% and 11%, respectively. Biological yield was 15% and 16%, respectively. The results also showed high correlation between grain yield and all measured traits and biological yield with all measured traits except harvest index.

The results showed that inoculation of rapeseed cultivars had a significant effect on yield and yield components under both stress and full irrigation conditions and Talayeh cultivar had the highest yield and yield components compared to other cultivars.