عنوان مقاله [English]
Rainfed farming plays an important role in the food production of many countries in the semi-arid regions of the world and includes 80% of the total usable agricultural land. Barley is cultivated in most parts of the world in areas that are threatened by moisture stress, the lack of different stages of plant growth from germination to seed setting and finally affect the grain yield. Studies show that the stress caused by lack of water in plants is one of the important factors of crop reduction in semi-arid regions. The use of biofertilizers improves yield by improving the physical properties of the soil and increasing soil fertility and increasing the availability of nutrients for plant uptake, among which mycorrhizal fungi are considered as the most important microorganisms. Mycorrhizal fungi are effective in nutrient uptake including phosphorus, water uptake in dehydrated conditions, hormone production, modulation of environmental stresses, improvement of root growth and effect on soil granulation. Since not much research has been done on the application of mycorrhizal fungi on dryland barley in the country and especially in Ilam province, the present experiment was conducted to investigate the effect of mycorrhizal fungi on yield, yield components and gas exchanges of dryland barley.
Materials and methods
In order to investigate the effect of mycorrhiza inoculation on yield and yield componentts and gas exchange of barley cultivars in rainfed conditions, a factorial field experiment carried out in factorial analysis based on randomized complete block design with three replications at the farm of Sarablah Agricultural Research Center station during 2019-2020 cropping season. Experimental treatments include barley cultivars (Mahali, Mahour, Khorram and Fardan) and fertilizer sources treatment including: control (no fertilizer source), 50% phosphorus fertilizer, mycorrhizal fungi (Glomus mosseae, Glomus etunicatum and Rhizophagus irregularis) Mycorrhizal fungi were +50% phosphorus fertilizer and 100% phosphorus fertilizer. In this study, the length of each plot was four meters, the number of rows in each plot was eight rows and the distance between the rows was 20 cm. The measured traits were: yield and yield components, as well as gas exchanges, including photosynthetic mesoton, transpiration rate, photosynthetic water consumption efficiency, mesophilic conductance, substomatal carbon dioxide concentration, and leaf temperature. The effect of the treatments on yield and yield componentts and gas exchange of the barley cultivars in the field was assessed using by SAS software, means were compared by Duncan's multiple range test method and graphs were drawn by Excel software.
Results and discussion
The results of this study showed that the interaction of cultivar×fertilizer sources on yield, grain yield components as well as gas exchange characteristics including photosynthetic mesoton, transpiration rate, photosynthetic water consumption efficiency, mesophilic conductance, substomatal carbon dioxide concentration, and leaf temperature in rainfed barley was significant. So that the maximum number of seeds per spike (32.3 seeds), 1000-grain weight (38.5 g), grain yield (4238.3 kg/ha), biomass yield (10123.3 kg/ha), photosynthesis rate (5.7 µmol Co2 m-2s-1), transpiration rate (4 mmol H2o m-2s-1), mesophilic conductivity (0.019 mmol co2 M-2S-1) and water use efficiency Photosynthesis (µmol co2 mol-1H2o) was obtained in Fardan cultivar ×Mycorrhiza+50% of phosphorus fertilizer compared to the control (no fertilizer source was used).
The results of this study showed that in rainfed conditions, yield and yield components, photosynthesis rate, transpiration rate, mesophilic conductance, photosynthetic water use efficiency in all cultivars of barley were significantly reduced. However, the use of mycorrhizal fungi in dryland conditions improved grain yield and gas exchanges. In this study, Barley Fardan×application of Mycorrhizal fungi caused a significant increase in yield and grain yield components by increasing photosynthesis and increasing photosynthetic water use efficiency as well as decreasing leaf temperature.