فهرست مطالب hassan nouriyani

Water stress is one of the most important threatening factors for the production of crop plants in the arid and semi-arid regions of the world. Understanding plant responses to drought is of great importance and also a fundamental part of making crops stress tolerant. Water stress reduces plant growth and manifests several morphological, physiological and biochemical alterations leading to massive loss in yield of major crops including Rye. Drought susceptibility of a genotype is often measured as a function of the reduction in yield under drought stress, while the values are confounded with differential yield potential of genotypes. The aim of this study was to evaluate the effect of water deficit stress on some physiological, biochemical traits and yield of three Rye cultivars.

This experiment was carried out as split plot based on randomized complete block design with three replications in Dezful region during 2014-2015 growing season. Treatments included water deficit stress (irrigation after 75, 1000 and 150 mm evaporation from Class A evaporation pan) in main plots and three rye cultivars (Stratoskaya, Danko, Montanum) were in subplots. The evaluated traits included chlorophyll a, chlorophyll b, carotenoids, soluble proteins, quantum yield of photosystem II, soluble sugars, proline content and grain yield. Analysis of variance was performed using statistical analysis system (SAS version: 9.3). The means were analyzed using the Duncan's test at 5% probability level.

The results showed that water deficit stress reduced the content of chlorophyll a (27%), chlorophyll b (32%), carotenoids (19%), soluble proteins (71%), quantum yield of photosystem II (28%), grain yield (33%) and in contrast, it increased the amount of soluble sugars (83%) and proline content (145%) compared to the control treatment. The slicing intersections of water deficit stress and cultivar showed that in terms of grain yield, Danko cultivar under irrigation conditions after 75 mm evaporation and Stratoskaya cultivar under irrigation conditions after 150 mm evaporation from the evaporation pan of Class A evaporation had the highest and lowest grain yields with 2414 and 1147 kg per hectare, respectively.

In general, it can be said that under irrigation conditions after 150 mm evaporation Montanum cultivar because of more photosynthetic durability and better osmotic regulation than the other two cultivars had more tolerance to water deficit stress and it had higher grain yield.

Since improving the efficiency of environmental resources utilization in intercropping is one of the essential strategies for achieving sustainable agriculture, Therefore, in order to assess some ecophysiological properties of maize S.C 704 in additive intercropping with mungbean, an experiment was conducted.  

The experiment was based on randomized complete block design with six treatments and four replications in Dezful region during the summer of 2018. Experimental treatments consisted of different additive intercroppingof maize-mungbean intercropping (adding 10%, 20%, 30%, 40% and 50% of optimum density of mungbean to optimum maize density) and a pure stand of maize (control).  

The results showed that the effect of different maize -mungbean additive intercropping treatments on leaf area index, leaf area duration, light absorption, crop growth rate, dry matter accumulation and light use efficiency was significant. But the relative growth rate was not significantly affected by the treatments. In this study, with increasing in mungbean density, the evaluated traits in all intercropping treatments were higher than that of pure maize. However, the additive intercropping treatment of maize+40% mungbean utilized higher leaf area index (5.28), leaf area duration (217 LAI-day), absorption of photosynthetically active radiation (18.12 MJ/m2), Crop growth rate (30.14 g/m2/day) and relative growth rate (0.0838 g/g/day) compared to the other treatments, resulting in the highest dry matter accumulation (1996.50 g/m2) and consequently the highest radiation use efficiency (2.91 g/mJ).  

In general, maize+40% mungbean treatment can be introduced as the best maize-mungbean additive intercropping system, regarding environmental resources consumption and dry matter production.

In order to investigate the effect of different levels of nitrogen on some grain storage compounds and quantitative and qualitative yield of three sunflower cultivars, an experiment was carried out as split plots based on randomized complete block design with four replications in Dezful region during 2017-2018. In this research, four levels of nitrogen fertilizer (0, 60, 120 and 180 kg ha-1 N) were considered as the main factor and three sunflower cultivars (Ghasem, Record and Progress) as a sub factor. The results showed that increasing nitrogen consumption reduced the percentage of oil, percentage of stearic acid and linoleic acid percentage but, protein percentage, oleic acid and palmitic acid percentage increased significantly. There were significant differences between different cultivars in grain yield and oil content where Qasem cultivar had the highest grain yield (3920 kg ha-1) and oil (1860 kg ha-1) with the consumption of 180 kg ha-1 N. Also, the results indicated that the highest correlation of grain yield with the studied traits belonged to oil yield (r=0.97**) followed by protein content (r=0.85**) and the lowest to linoleic acid (r=-0.58*). In general, it can be stated that more nitrogen consumption has been effective in increasing the quality and quantity of sunflower and Qasim cultivar had a higher ability to absorb nitrogen in order to increase yield per unit area.

Today, various technologies have been developed to improve seed quality with the aim of increasing the percentage, speed and uniformity of germination and improved seedling establishment under different environmental conditions. One of these technologies is seed pre-treatment or seed priming. In this regard, some studies confirmed that pre-treatment of seeds with hormones and plant growth regulators improve germination behavior and its related indices, including average germination time, seed vigor, radicle length, plumule length, germination rate and seedling establishment in primed seeds of sesame. Cognizant of the sensitivity of the germination process as the first plant developmental stage and the importance of improving germination indices and sesame seedling establishment, the aim of this study was to evaluate the seed priming efficiency, using salicylic acid, methyl jasmonate and humic acid in the germination performance, biochemical changes and early seedling growth of two sesame cultivars including Yellow white and local cultivar of Dezful. This experiment was conducted as a factorial based on a completely randomized design with four replications in the seed technology Laboratory of Safi Abad Dezful Agricultural Research Center in the summer of 2015. The first factor was seed pre-treatment with distilled water (control), salicylic acid 0.1mM, methyl jasmonate 1µM, and humic acid 1.5% and the second factor was two varieties of sesame including Yellow white and the local cultivar of Dezful. Germination percentage, germination rate, seed vigor index, radicle length, plumule length, allometric coefficient, proline content, soluble proteins and catalase enzyme activity were determined to compare the treatments. The results of the experiment showed that seeds priming had a significant effect on germination percentage, germination rate, seed vigor index, radicle length, plumule length, allometric coefficient and seedling biochemical changes, and improved them. The effect of cultivar on all the traits studied, except mean daily germination and plumule length, was not significant. In this research, the Dezful cultivar had an average of 13.52 seeds per day with higher germination rates, compared with the other cultivar (Yellow white). In addition, the interaction of priming × cultivar was significant only in seed vigor index and allometric coefficient, where the comparison of the mean values indicated that the highest seed vigor was obtained by using humic acid 1.5% in the Dezful cultivar (10.09), while the highest allometric coefficient in seed pre-treatment with methyl jasmonate was found in the Yellow white cultivar (1.57). In this study, the most effective seed priming treatments for improving germination, biochemical changes and seedling growth of sesame was humic acid 1.5%, recorded for the local cultivar of Dezful. Seed priming with humic acid 1.5% was significantly better than the control and Dezful cultivar’s germination performance was better than that of Yellow white cultivar; therefore it can be said that pre-treatment of seed with humic acid with significant effects on germination characteristics of sesame can be more effective in establishment of seedlings. It is advisable to use this organic acid for better root system development and sesame seedlings establishment, which is a major problem at the beginning of the growing season.   Highlights: Humic acid was the most effective seed priming treatment on germination characteristics, biochemical changes and seedlings growth of sesame. The effect of seed priming treatments on the germination characteristics of the Dezful cultivar was more pronounced than that of Yellow white.

The effect of vermicompost on morpho-physiological characteristics and yield of green bean plant under drought stress were studied in Dezful during 2016. Experimental design was split plot based on randomized complete block design with four replications. In this research, drought stress was carried out in irrigation intervals at four levels as irrigation after 100, 140, 180 and 220 mm evaporation from class A evaporation pan in the main plots, and vermicompost was assigned as subplots at four levels (0, 4, 8 and 12 t.ha-1). The results showed that the effect of different levels of stress on plant height, pod length, number of pods per plant, yield of green pod, grain yield, protein content, chlorophyll a, chlorophyll b and carotenoids were significant, but the number of grain per pod was not significant. The effect of vermicompost on all studied traits was significant except for the number of grain per pod and carotenoids. Also, the interaction of treatments was significant only on the yield of green pod and grain yield. Regression relations showed that the highest yield of green pods and grain yield produced under no stress condition (S0), with the application of 8.40 and 8.12 t.ha-1 vermicompost. Increasing of vermicompost consumption reduced the effects of stress and improved yield.