Iranian Journal of Seed Research

In order to evaluate the electrical conductivity and seedling growth characteristics of red bean seed grown under drought stress and foliar application of zinc and manganese, a split factorial experiment was conducted in a Randomized Complete Block Design in the field and also laboratory experiment at Shahrekord University in 2011. Factors included three levels of drought stress (irrigation after 50, 70 and 90 mm evaporation from class A pan) as the main plot and three levels of zinc foliar application (with water, 100 and 200 grams per hectare zinc), and three levels of manganese foliar application (with water, 150 and 300 grams per hectare manganese) in a factorial combination as subplot. The results showed that severe drought stress led to decrease of electrical conductivity while the seedling and root length of red bean seed were increased. In the measured characteristics, Mn foliar application had a significant effect on electrical conductivity and root dry weight. In different Mn foliar application treatments, the lowest electrical conductivity was related to control while the maximum seedling dry weight was observed at 150 g Mn foliar application per hectare. Zn foliar application had a significant effect on all the traits measured during this experiment. Based on means comparison, the highest seedling dry weight, shoot, seedling and root length, as well as the lowest electrical conductivity, belonged to the 100 g Zn foliar application per hectare. The highest root dry weight was obtained for 200 g Zn per hectare which no significant difference was observed with 100 g Zn per hectare. According to the results of this experiment, mild stress and foliar application of zinc and manganese led to increasing the quality of the produced seeds. In total, foliar application of zinc and manganese (at the amount of 100 and 300 g ha^-1 respectively) with mild stress (irrigation after 70 mm evaporation from class A pan) are recommended for the production of seeds with high vigor under this region conditions.

Extended Abstract
Introduction: One of the biological methods of weed control is the use of allelopathic substances or herbal secretions that have the potential to inhibit growth weeds. Wheat allelopathic studies include the study of wheat allelopathy against other crops, weeds, pests and diseases, isolation and identification of allelopathic compounds, the effects of wheat toxicity on self-storage and management of wheat residues. Wild mustard (Sinapis arvensis) is a problematic weed in the country, especially in Golestan province. The present study was conducted to investigate the allelopathic potential of four wheat cultivars to use those cultivars in integrated weed management system to reduction growth mustard weed.
Materials and methods: A factorial experiment was conducted in completely randomized design with three replications at Physiology Laboratory of Golestan Agricultural Research Center. Treatments included concentrations of 0, 2.5, 5, and 7.5% aqueous extract of aerial and underground organs of four wheat cultivars (Morvarid, Moghan, Tajan, and Arta) with 6000 polyethylene glycol treatment in four concentration (zero, 2.5, 5, and 7.5 percent). Three-parameter logistic model was used to evaluate the allelopathic potential of wheat genotypes for reducing the percentage of wild mustard germination and liquid chromatography (HPLC) was used to determine the phenolic acids composition in wheat cultivar extract.
Results: Extract of shoot of all wheat cultivars reduced root length of wild mustard in comparison of control. Wheat cultivars reduced shoot length of wild mustard by 28% to 51% compared to control. The highest reduction in mustard shoot length was obtained from the Morvarid extract. Increase in shoot extract concentration of Arta to 7.5%, reduced root and shoot dry weight as 47 and 29% in compare of control treatment and Moghan cultivar in the same concentration (7.5%) caused reduction in root and shoot dry weight with 68 and 41% respectively. The highest reduction in germination indices of wild mustard was obtained from high concentrations of Morvarid and Moghan wheat extract. It was also found that with increasing concentration of polyethylene glycol (PEG) growth indices and germination components of wild mustard seed decreased, but this decrease was not significant. This confirms that the osmotic potential of the extract concentration is not involved in the exacerbation of the allelochemical effect and the likelihood of osmotic effect seems poor. In total, Morvarid cultivar with 25.34 mg phenolic acid content had the highest phenolic acid concentration, which was approximately three times more than that of Tajan, 1.5 times Moghan and three times of Arta cultivar. Morvarid cultivar had higher concentration of vanillic acid and ferulic acid than the other three cultivars. Overall, the least allelopathic effect was observed in Tajan cultivar and the most allelopathic effect was in Morvarid cultivar.
Conclusion: Among the cultivars studied, the highest inhibition was related to Morvarid cultivar. The results also showed that the highest amount of inhibition was related to shoot extract so that the root extract inhibition was less than the shoot on studied traits. In general, the results of the present study showed that some wheat cultivars have greater inhibitory potential against wild mustard weed, which can be used in breeding programs to produce cultivar with high allelopathic potential. Awareness of this issue is more important, especially in sustainable weed-management. Therefore, it is suitable to perform comprehensive studies on their allelopathic potential so that they can be used in agriculture, including combating with weeds, pests and plant diseases, breeding crop and horticulture, design herbicides and pesticides that is provide environmentally friendly, safe, and biodegradable.

 
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