In order to study the effects and the interference of wild oat over two varieties of spring barley, a greenhouse experiment was conducted in Tabriz University. Experimental designe was complete randomized design with three replications based on factorial experiment. The treatments were four density of the barley including 2, 4, 6 and 8 plants per pot, four density of the wild oat including 2, 4, 6 and 8 plants per pot and two barley varieties (Joonob and Kavir). For all densities of barley and wild oat, one pot was considered as control (monoculture of barley and wild oat). The results indicated that, Jonob variety was superior than the Kavir. The wild oat interference decreased the number of seeds in the primary spike, biological seed yield per plant and one 1000 seeds weight in compare with control. The 6 and 8 densities of wild oat decreased number of tiller in barely in compare with control. The highest amount in whole attributes in barely related to 2:2 (Joonob barely: wild oat) and the lowest amount related to 8:8 (Kavir barely:wild oat). Reducing rate in 2, 4, 6 and 8 densities of wild oat in barely in compare with control in seed yield of barely was equal 48.04, 53.35, 65 and 70.39 percent. This results showed that with increasing of wild oat density whole attributes of barely reduced, while Kavir was more sensitive than Joonob against wild oat.

The green fodder, grain yield and yield components of three triticale and two barley cultivar were compared in a split plot experimental design in Moghan Agricultural Research Station during two consecutive cropping seasons (2000-02). The main plot was allocated to harvested and non-harvested green fodder treatments, and the subplot was assigned to three triticale cultivars (4108, 4116 and Mus"S"/Beta"S") and two barley cultivars (Dasht and LB). Combined analysis of variance for green fodder indicated significant differences among the cultivars (P < 0.01).The highest green fodder (21.01 tha-1) was obtained from barley cultivar LB. Three triticale cultivars 4116, 4108 and Mus"S"/Beta"S" produced 17.24, 15.79 and 14.1 tha-1 green fodder, respectively. The differences among the cultivars were not significant. Barley cultivar Oasht had the lowest green fodder. Combined analysis of variance for agronomic characters showed significant difference among the cultivars for grain yield, plant hieght, spike length, number of kernels per spike and 1000kw (P < 0.01).The highest and lowest grain yield belonged to triticale cultivar 4116 and barley cultivar Dasht, respectively.

This experiment was arranged as a split-split plot in a randomized complete block design with three replications at the research farm of Isfahan University of Technology in 2017 to evaluate the effect of drought stress and nitrogen fertilizer on yield and some physiological traits of six barley cultivars. Experimental factors included two irrigation regimes (55 and 85 percent of available soil water), two levels of nitrogen fertilizer (The available amount in the soil (84kg / ha) and 62.5 kg nitrogen from the urea source containing 45% nitrogen) and foreign (Amistar, Campagen, Funky, Mastesca, Shangrila) and Iranian (Yousef) barley cultivars. The results showed that drought stress decreased grain and straw yield by reducing the content of chlorophyll a and b, carotenoid content and the maximum potential quantum efficiency of photosystem II but increased proline and malondialdehyde contents. Nitrogen application increased grain and straw yields under normal irrigation conditions while the opposite effects were observed under drought stress condition. Among studied cultivars, Yousef had the highest grain yield and Funky produced the highest amount of straw under normal irrigation conditions. Normal irrigation and nitrogen application increased the plant height, chlorophyll a but decreased malondialdehyde in all cultivars. The highest grain and straw yield of cultivars were obtained by nitrogen application under normal irrigation. The results from this experiment showed that nitrogen application is not an appropriate strategy to reduce the negative effects of drought stress on the yield of studied barley cultivars.

Mycorrhiza fungus is of special importance in organic agriculture and in relation to the coexistence of all root characteristics of the host plant is affected and also improves the water relationship in the host plant.  With application of mycorrhizal fungus, the plant absorbs soil water better and as a result, by increasing the relative moisture content of the leaves, the stomata are open for a longer time and carbon dioxide processing is done optimally, resulting in more photosynthesis, which ultimately leads to increased yield. The aim of this research in rainfed agriculture is to reduce the stresses on rainfed wheat. In rainfed wheat cultivation, the plant gets its water requirement from rainfall. In most cases, the plant water needs are not met in this way. Due to the reduction of grain yield of rain-fed barley cultivars, new achievements can be reached by investigating the role of plant growth-promoting bacteria on physiological and biochemical traits under rain-fed conditions. Considering that no research has been reported on the role of plant growth promoting bacteria on rainfed barley in the country and especially in Ilam province. Therefore, the present experiment was conducted to investigate the effect of plant growth promoting bacteria on the activity of antioxidant enzymes and physiological traits of rain-fed barley cultivars.
Materials and

In order to investigate the effect of inoculation with mycorrhizal fungi on some physiologic and biochemicaltraits of barley cultivars in rainfed conditions, a factorial field experiment was carried out in the form of a randomized complete block design with three replications in the farm station of Sarablah Agricultural Research Center during 2019-2020 cropping season. Experimental treatments including factor of barley cultivars (Mahali, Mahour, Khoram and Fardan) and fertilizer sources treatment including: control (without fertilizer source), 50% P fertilizer, mycorrhizal fungus (Glomus mosseae, Glomus etunicatum and Rhizophagus irregularis), mycorrhizal fungi + 50% P chemical fertilizer and 100% P chemical fertilizer.
Results and

The results of this experiment showed that the interaction between cultivar×fertilizer sources had a significant effect on the activity of some antioxidant enzymes and physiological properties. Fardan cultivar× mycorrhizal fungi +50% P chemical fertilizer increases the activities of ascorbate peroxidase (14.3 µmolmin-1 mg protein-1), gluthathion peroxidase (3.5 µmol.min-1 .mg protein-1), catalase (12.1 µmolmin-1 .mg protein-1), peroxidase (14.8 µmol.min-1 .mg protein-1), super oxid dismutas (25.4 µmol.min-1 .mg protein-1), chlorophyll a (3.5 mg.g-1 fresh weight), chlorophyll b (3.3 mg.g-1 fresh weight) and reduces malonde aldeyede (20.4 nmol.g fresh weigh leaf) and hydrogen Peroxide (0.26 mmol.g-1 FW) and Mahali cultivar× control treatment (without fertilizer sources) had the lowest activities of ascorbate peroxidase, peroxidase, superoxide dismutase and photosynthetic pigments.

The results of this study showed that in the dryland conditions of the region, physiological traits (leaf chlorophyll content) were significantly reduced in all studied barley cultivars. In this study, the maximum activity of hydrogen peroxide and malondealdeyede in the Mahali cultivar×control treatment was observed, but when inoculation was used with mycorrhizal fungus, observed an increase in physiological characteristics. Fardan cultivar×Mycorrhiza+50% P fertilizer with maximum activity of photosynthetic pigments and antioxidant enzymes (superoxide desmutase, catalase and peroxidase) which resulted in increased growth and yield. According to the results of this study, among the rainfed barley cultivars used, Fardan cultivar with mycorrhizal fungi +50% P fertilizer can be recommended in rainfed agriculture of the region.

Acknowledgements

This research was derived from a research project that was carried out at Sarablah Agricultural Research Station. Thanks to all the colleagues who accompanied and helped the authors during the implementation of this study.

Barley is known to be an allelopathic plant and its allelopathic potential on weeds, and some other crops has been proven. Increasing use of herbicides has an adverse environmental impact and increases the weed resistance to herbicides. Eco-friendly methods for controlling weeds reduce the amount of herbicide use and reduce the damage caused by it. Some plants have alternate properties (allelopathies) that can be used to reduce or stop the growth of other plants, especially weeds. Allelopathy is an interference mechanism based on any direct or indirect effect (primarily inhibitory) by one plant on another through the release of chemicals that escape into the environment. Barley (Hordeum vulgare L. ssp. vulgare) is well known for its allelopathic compounds. The decomposition of barley plant residues in the soil, release numerous allelochemical compounds such as phenolic compounds, flavonoids, synoglycosides, alkaloids and polyamines. Till now 44 chemicals have been identified as potential allelochemicals that contribute to its allelopathic activity in Hordeum vulgare. The present work aimed to study the allelopathy potentials expressed by residues as straw among two barley genotypes on rhizome growth and physiological attribute of bindweed (Convolvulus arvensis L.).

This experiment was conducted in 2013 at Islamic Azad University, Shoushtar Branch. The experiment was factorial based on completely randomized design (CRD) with four replications. Four different amounts (10, 20, 30 and 40 g per one kg soil) of two barley cultivars (local ecotype and Sarasary 10) residual were prepared. Rhizomes were harvested from a depth of 30 cm soil and cultivated in the pot. The culture medium included plastic pots of 30 cm in diameter. The traits included seedling weight and length, malondialdehyde concentration, fatty acid percent, α-amylase activity, catalase activity, peroxidase activity, glutathione reductase activity, GA and ABA concentration of bindweed rhizome. The concentration of GA and ABA hormones was investigated based on the Kamal method. Statistical analysis was made using the SPSS Ver.13 statistical program. Significantly different means were separated at the 0.05 probability level (p = 0.05) by the least significant difference (LSD) test. Pearson’s correlation analysis was also conducted among different variables.

Results indicated the effect of genotype, residual amount and their interaction on rhizome malondialdehyde concentration, fatty acid percent, α-amylase activity, catalase activity, peroxidase activity, Glutathione reductase activity, GA and ABA concentration. Increasing the amount of residues for the local genotype caused a significant decrease in seedling fresh weight. The lowest fresh weight of bindweed was 40 g residues of local genotypes, in which was 73.6% lower than the control without residues. Increasing the amount of local and Sarasary 10 residues in the soil caused a significant reduction in the length of the bindweed seedlings. The negative effect of local ecotype residual on α-amylase activity was more than modern genotype. The mixing of 40 g residues of local ecotype and Sarasary10 genotype with soil decreased this enzyme by 38% and 79.5%, respectively, compared to the control without residues. Increasing the amount of residuals, reduces gibberellin hormone and increased rhizome the ABA content. The slope of the changes in gibberellin hormone and the increase of ABA in the local ecotype was higher than the modern genotype. Antioxidant enzymes increased in response to an increase in the amount of residues up to about 20 grams in the pot and then decreased significantly. Reducing antioxidant enzymes at high levels of barley residues led to an increase in the amount of fatty acids and Malondialdehyde, indicating the peroxidation of the cell membrane. In general, the residuals of local genotype compared to cultivar Sarasary 10 had a more harmful effect on all studied traits of bindweed rhizome and seedling. It seems that in areas where bindweed is dominant, it is possible to use local barley residuals to reduce the damages.