فهرست مطالب m. pour yousef

Weeds are the most important limiting factors in agricultural systems and the use of mulch is considered as a suitable solution in the ecological management of weeds. In order to evaluate the coriander yield and its weed control, a factorial experiment was conducted at the research farm of the Faculty of Agriculture, University of Zanjan in 2020. The first factor was the types of mulches including ratios of 100 % (40.0 kg ha-1), 66 % (26.4 kg ha-1), and 33 % (13.2 kg ha-1) of clover (Trifolium alexandrinum L.) and 100 % (20.0 kg ha-1), 66 % (13.2 kg ha-1), and 33 % (6.6 kg ha-1) of alfalfa (Medicago scutellate L.) as living mulches, wheat straw (Triticum aestivum L.) (one kg m-2) as a non-living mulch, and a non-mulched treatment and the second factor was weed control including complete weed control, once-weed control and non-weed control. The results showed that the effects of the treatments of mulch type and weed control were statistically significant on the components of yield and yield of coriander. The highest grain yield (1601.4 kg ha-1), biomass yield (3901.0 kg ha-1) and essential oil yield (3.35 kg ha-1) were recorded in wheat straw mulch under complete weed control conditions. Clover at densities of 100 % and 66 % caused suffocation and complete destruction of coriander plants. Therefore, the grain yield and biomass production of coriander in these treatments were equal to zero. Alfalfa at low densities had no significant effect on weed control. Complete control of weeds caused a significant increase in all evaluated traits in coriander. The results of the present study showed that wheat straw mulch is a suitable solution for controlling coriander weeds, which not only does not interfere with the growth of coriander but also causes effective control of its weeds. Therefore, considering the importance of integrated control of weeds in sustainable agricultural systems, the use of wheat straw mulch can be introduced as one of the strategies to reduce the use of chemical pesticides and reduce environmental pollution.

Common bean (Phaseolus vulgaris L.) is a food crop with high protein, fiber, and minerals. One of the important issues in the formation of seed yield is how photosynthetic materials are allocated in plants. This may be especially important when the plant is experiencing drought stress. Brassinosteroids are a group of steroid hormones that have been implicated in a wide range of physiological processes. Brassinosteroids increase crop yield by altering plant metabolism and protecting plants from environmental stresses. Considering that one of the major problems of agriculture is water shortage, the present study was assessed aimed to investigate the effect of Epibrassinolide application on the allocation of photosynthetic materials and some traits related to drought resistance in two common bean genotypes under optimal irrigation and drought stress conditions and the possibility of increasing common bean seed yield by using this hormone.

In order to investigate the effect of Epibrassinolide application on photosynthetic material allocation and the possibility of increasing common bean seed yield by application of this hormone, an experiment was conducted in split factorial based on randomized complete block design at the research farm of the University of Zanjan during 2016-2017. In this experiment, optimal irrigation and drought stress were applied to main plots and common bean genotypes (at two levels of Kusha cultivar and COS16 genotype) and different concentrations of Epibrassinolide (at four levels of no application or control, 2, 4, and 6 μM) were allocated to sub plots as factorial. In the flowering stage, drought stress was applied and simultaneously with drought stress, common bean plants, were sprayed with Epibrassinolide. In this study, relative water content, proline content, and malondialdehyde content were studied at the peak of the drought stress. Also, dry weights of leaf, stem, and pod and the ratio of leaf, stem, and pod dry weights to total plant weight were studied at two times (peak of the drought stress and one week after re-irrigation).

The results showed that drought stress decreased dry weights of leaf, stem, pod, and seed yield compared to the optimal irrigation. Common bean plant under drought stress allocated less photosynthetic materials to leaves and stems and more photosynthetic materials to pods. The Kusha cultivar under optimal irrigation had the highest seed yield (with an average of 3025.45 kg ha-1) and the COS16 genotype under drought stress had the lowest one (with an average of 980.89 kg ha-1). The Kusha cultivar in optimal irrigation condition was the superior genotype due to its high seed yield, but drought stress had a more negative effect on the Kusha cultivar. Also, application of different concentrations of Epibrassinolide increased dry weights of leaf, stem, pod, and seed yield compared to the control. The highest seed yield was obtained by application of 2 μM Epibrassinolide (with an average of 2068.2 kg ha-1). So that, application of this concentration increased the seed yield by 46.07% compared to the control. Epibrassinolide application also increased the drought stress tolerance by decreasing the amount of malondialdehyde and increasing the relative leaf water content and proline content.

Therefore, application of Epibrassinolide can be suggested as a solution to increase common bean seed yield and increase drought tolerance of this plant. In addition, obtaining comprehensive information on the positive effects of Epibrassinolide requires the study of this hormone in different climatic conditions.