p .hassibi

The food providing for the growing world population has always been one of the main concerns of mankind and rice is one of the most important sources of human food. The importance of rice plant in human nutrition and the necessity of achieving self-sufficiency in its production through increasing yield is not hidden from anyone. Among the solutions that humans have used to deal with this problem is choosing the right planting method, planting date and cultivars. Currently, the cultivation of this plant is carried out in most parts of the world in the form of transplanting. Supplying sufficient amount of water is necessary to increase crop production and lack of water is one of the basic limitations in the development of rice cultivation in some regions of the world. Therefore, it is an undeniable necessity to choose a suitable bed for planting plants that will reduce water consumption and produce optimal crops. Also, planting date can have a significant impact on crop growth and rice yield, and it is important to determine the most suitable cultivars for a special planting date. Despite the great importance of different rice transplanting beds on its crop production and the optimal management of these beds through the application of appropriate planting dates that can have a significant impact on crop production, so far not many studies have been conducted in Khuzestan.

This research was designed to determine the feasibility of establishing rice cultivar seedlings in dry beds and compare it with wet conditions at different times of seedling production. The experiment was carried out during the cropping years of 2021 and 2022 at the Shavur research station in Khuzestan province, located 65 km north of Ahvaz. It was conducted using a split-plot design within a randomized complete block design with three replications. The main factor, planting beds for the seedlings, included transplanting in a conventional bed (paddling), transplanting in a bed with field capacity, transplanting in a flat bed under dry conditions, and transplanting in a raised bed under dry conditions. The sub-factor was the date of seedling production, which included June 2, June 12, and June 23. The rice cultivars, which were the sub-sub-factors, included Champa, Anbori, Germez-Paboland, and Daniyal.

The results of comparing the average of traits showed that the highest yield of paddy in the two years of the experiment was related to the flat planting bed and the planting date of 2 June (5190 kg.ha-1 in first year, 6536 kg.ha-1 in second year, respectively in Anbori, Germez-Paboland and Champa). Rice yield showed a high correlation with biological yield, number of panicles per square meter, panicle length and plant height. The lowest yield of paddy in the two years of the experiment belonged to the conventional bed (2811 kg.ha-1 in 12 June in first year, 2964 kg.ha-1 in 23 June in second year, respectively in Anbori, Germez-Paboland and Daniyal).

Long-term waterlogging in the method of gerbera cultivation has caused disturbances in the growth and production of the plant, resulting in a decrease in paddy yield. Therefore, it can be concluded that different beds for transplanting have a significant impact on rice crop production. Optimal management of these beds, through the application of appropriate planting dates and suitable cultivars, can effectively improve crop production. Also, according to the obtained results, although the Daniyal cultivars is a high-yielding cultivars, compared to the local varieties, it could not achieve better performance under the conditions of the treatments investigated in this experiment.

Mung bean (Vigna radiata L.) is one of the most important legumes in the world. This nitrogen-stabilizing plant has rapid growth and a short growth period, leading to improved soil fertility. Mung bean is widely cultivated in tropical and subtropical regions of Asia due to its high adaptation range. Plants are obligate aerobic organisms and thus depend on O2 to grow and compete successfully with neighbouring plants in natural environments. Waterlogging stress is one of the most important factors limiting the planting of mungbean under Ahvaz conditions.

In order to study the effects of waterlogging stress on some agronomic and physiological characteristics of two Mung bean cultivars, a pot experiment was conducted as split-plot factorial in a completely randomized block design with three replications in the field. The main plots were different growth stages consisted of: vegetative growth stage, the beginning of flowering, grain filling stage, and three growth stages. The combination of stress levels (control and waterlogging stress) and two Mung bean cultivars (Hindi and Omrani) were as sub plots.

Waterlogging was caused to decrease significantly dry matter and grain yield in both cultivars at each growth stages, In Hindi cultivar, the highest grain yield reduction was observed at flowering stage and the least difference was observed in waterlogging stress at all three growth stages. In Omrani cultivar, the highest grain yield reduction was observed in waterlogging stress at all three growth stages, and the least grain yield decrease at flowering stage Overall, the reductions in dry weight and grain yield were higher in Omrani than Hindi cultivar at three growth stages. Therefore, in stress-prone areas such as Ahvaz where summer plants such as Mung bean are exposed to waterlogging stress at different growth stages, Hindi cultivar is suggested for cultivation. Waterlogging stress did not show a significant effect on grain weight and grain number per pod, but significantly reduced the number of pods per plant. The number of pods per plant was significantly more important in determining yield and had a positive and significant correlation (r = 0.846 **) with grain yield.

The reason of difference between two cultivars was the better physiological compatibility of Hindi cultivar under stress conditions, including higher levels of photosynthesis and photosynthetic pigments contents. When plants were treated only with water logging stress in one growth stage, the Omrani cultivar could compensate some damages due to its infinite growth and phenological flexibility, as the period of pod formation was longer in this cultivar. SPAD number had the highest correlation with grain yield (r = 0.707 **) compared to other photosynthesis-related traits and could be used as a marker trait for selection of tolerant cultivars because of its ease, speed, cheapness and the possibility to measure this trait in the field.

Camelina [Camelina sativa (L.) Crantz] oilseed is a low-input crop that grows and yields well in semiarid regions with low-fertility or saline soils in comparison with other crops. Camelina seeds contain 30–40 percent oil. Camelina is an annual plant from the Brassicaceae family that has short and fast growth. Camelina is well adapted to cool temperate and semi-arid climates, it is more tolerant of drought and spring freezing than rapeseed (Brassica napus L.). Also, Resistance to some diseases and pests of other members of Brassicaceae plants is another important features of this plant. Research-based information is lacking to provide basic agronomic recommendations for Camelina. In general, yield and yield components of Camelina seeds depends on nitrogen fertilization, planting time and climatic conditions. Camelina responds differently to fertilizer management and planting date in different climatic and soil conditions. Selection of crop managements such as planting date and fertilization can increase the quantitative and the qualitative yield of this plant.

In order to evaluate the effects of nitrogen fertilizer on agronomic characteristics in Camelina under different planting dates, a study was conducted in split-plot based on randomized complete blocks design with three replications at the research field of Agricultural College, the Shahid Chamran University of Ahvaz, located in the southwest of Ahvaz and the western bank of the Karun River with 31°19׳ʹ N; 48° 41׳ʹ an altitude of 22 meters above sea level during 2018-19 growth season. Experimental factors included planting date in three times (November 6, December 6 and January 5) as the main plots and nitrogen fertilizer at four levels (0, 23, 46 and 69 kg.ha-1) as the subplots. The plant material (seed) of this research was Camelina sativa cultivar Soheil which was prepared from the Biston Shafa Knowledge Foundation Company. Half of the nitrogen fertilizer was spread with phosphorus and potassium in the surface of each experimental unit and mixed with soil before planting. The other half of nitrogen fertilizer used in three sections during three stages of plant phenology included True four leaves, beginning of stem elongation and beginning of silicle emergence.

Analysis of variance of traits showed a significant difference between nitrogen levels at each level of planting date in terms of all traits studied, including grain yield, biological yield, harvest index, plant height, percentage and oil yield, etc. Generally, based on the results of the analysis of variance, in all three planting dates. The highest grain yield (2653.8 kg.ha-1) was obtained from the first planting date and 46 kgN.ha-1 treatment and the highest harvest index in second planting date and 46 kg nitrogen treatment was measured. The highest oil yield (737.9 kg.ha-1) belonged to the first planting date and the level of 23 kgN.ha-1. However, the highest protein percentages (28.53) was obtained in the second planting date and 69 kg nitrogen treatment. Regarding to the other traits, it was observed that the optimal use of nitrogen fertilizer led to the improvement of the studied traits such as the number of sub-branches, silicle per plant, seed per silicle and 1000-grain weight, but delay in planting date caused the mean of these traits decreased significantly.

In general, the results of this study showed a significant response of Camelina to the amount of nitrogen used and planting date, so that in early planting (November 6) was obtained the highest grain yield, yield components, biological yield, oil yield and protein percentage. But in late planting, especially the third planting date, all the studied traits were reduced due to the collision of the plant reproductive stage with the high temperature at the end of Khuzestan growth season and the reduction of the plant growth cycle. Under three planting dates, nitrogen fertilizer application up to 46 kgN.ha-1 increased grain yield, oil yield and some yield components. Based on the results of this experiment, in order to obtain maximum grain and oil yield of Camelina, it is important to consider planting date and optimum nitrogen use.

Camelina is an annual oilseed plant of the Brassicaceae. Resistance to some diseases and pests of other members of Brassicaceae plants is one of the important features of Camelina. In the experimental sowing of this plant in Ahvaz in the cropping year 2018-2019, while the seeds were still immature, silicles shattering was observed in some camelina plants in experimental plots. After careful observation, it was discovered that some ants were cutting off the plant silicles and transferring them to their nests. Damages by these ants to Camelina plants were not limited to availibility of plants on the farm. These damages were also observed at the time of harvesting and counting of yield components. The ant was identified as Messor ebeninus Santschi, 1927 (Myrmicinae: Formicidae). This species has previously been reported from northern and southwestern of Iran. Collected specimens are preserved in the insects and mites collection, at the Department of Plant Protection, Faculty of Agriculture, Shahid Chamran University of Ahvaz. This is the first report of insects damage to Camelina in Iran.

In order to investigate the chilling effect and consequently oxidative stress on anti-oxidant system of two rice cultivars a field experiment was conducted in Research Center of Agriculture and Natural Resource of Khouzestan in February and March 2011. The experiment was conducted in a split plot arrangement using a randomized complete block design with three replications. The main plot consisted of three sowing dates, including19th and 28th of February and 10th of March and two rice cultivars (Champa and Dollar) were randomized in sub-plots. Results showed that low temperature decreased the activity of anti-oxidative enzymes including Peroxidase (POX), Catalase (CAT) and Ascorbate peroxidase (APX) of leaf and root of both cultivars significantly. The lowest activity was in Dollar variety. Amount of Malondialdehyde (MDA) increased significantly during chilling stress. The largest amount of MDA was in the leaves and root of Dollar cultivars (59.8 and 20.95 mM. grFW) in second sowing date. Protein content of leaf and root of two cultivars was decreased. Therefore, Champa cultivar due to effective anti-oxidant system and decreased of MDA content was more tolerant chilling and oxidative stress in comparison to Dollar cultivar.

To investigate water deficit stress influence on stem elongation, flowering stage and some physiological characters of three canola (Brassica napus) cultivars including total dry matter, grain yield, total soluble sugars and starch, proline and osmotic potential this study was carried out in the green house of Shahid Chamran University of Ahvaz in 2008-2009 growing season. The experiment was factorial based on complete randomized design arrangement in three replications. The first factor comprised cultivars (including Hyola 308, Hyola 401 and RGS003) and the second factor was water deficit stress including water deficit in the early stem elongation to early-flowering stage (D1), early-flowering stage to early sac appearance (D2), early stem elongation to early sac appearance (D3) and normal irrigation conditions (D4). The results showed that the lowest and the highest reduction in shoot dry matter and grain yield was measured in Hyola 401 and Hyola308, respectively. The lowest shoot dry matter was in Hyola 308 (from the early stem elongation to early sac emergence stages) (22 grams per plant) and the highest shoot dry matter was in Hyola 401 (74 grams per plant) in normal conditions. In the stress conditions, shoot dry matter in all cultivars decreased. The amount of reduction during the flowering stage was more than early stem elongation stage showing more sensitivity of flowering stage to the stem elongation stage in water deficit stress. The interaction of water stress and variety showed significant differences in total soluble sugar, starch, proline, osmotic potential (P≤ 0.01), shoots dry matter and grain yield (P≤ 0.05). Furthermore, in the stress conditions participation in osmotic regulation process and reduction of negative effects of water deficit stress increased the amount of the total soluble sugars and proline of leaves. The lowest leaf osmotic potential (-2.23 Mpa) and the highest osmotic potential (-1.65 Mpa) were determined in Hyola 401, and Hyola 308 for D3 and D4 respectively. Decrease (become more negative) of osmotic potential because of more tolerance of Hyola 401 to water deficit stress was also assessed. According to the results of this study, Hyola 401, RGS003 and Hyola 308 were assessed for tolerance, semi tolerance and susceptibility to water deficit stress respectively.