فصلنامه اکوفیزیولوژی گیاهان زراعی
پیاپی 32 (زمستان 1393)

A field experiment was conducted in 2012 at the Agricultural Research Station of Motahari of Sabzevar¡ to determine the influence of different crop management practices and weed interference duration on grain yield and yield components of chickpea (Cicer arietinum L.). A split plot experiment was employed in randomized complete block design with three replications. The main plots consisted of three crop management practices (Low¡ Medium and High input levels) and sub plot of five weed interference duration (0 as control¡ 15¡ 30¡ 45 and 60 weedy days after chickpea emergence). The results showed weed density¡ weed dry weight and number of plants per pod were not affected by crop management practices¡ however¡ plant height¡ biological and economic yield were inflenced by crop management practices. High input level had the highest plant height¡ biological and economic yield. Increased interference reduced yield¡ number of plants per pod and number of branches per plant of chickpea. Yield loss after full-season weed competition (60 days interference) was 80.60% as compared to control. Although increasing of weed interference reduced weed density but weed dry weight was increased. Fitted logistic regression function coefficients showed that the onset of yield loss was earlier (24.5 days after emergence) at low input levels while at high input levels it was postponed to 26 days after emergence. It can be conducted that increasing interference duration would reduce yield and yield components of chickpea¡ but under high input conditions competitiveness of chickpea will be increased.

An experiment was conducted at research farms of the Rice Research Institute of Iran (at Amol, Mazandaran province) to study the effect of different irrigation levels on the population of barnyardgrass (Echinocloa crus-galli (L.) Beauv.) and agronomical traits related to paddy yield of two rice cultivars (Tarom-Mahali and Shafagh). Treatments were arranged in split plot experiment based on randomized complete block design with three replications. Main-plots were two rice cultivars (Tarom-Mahali and Shafagh) and sub-plots were five levels, four levels of irrigation (0, 5, 8, 12 cm of water depth) and a weed control treatment. Results showed that cultivars and irrigation levels had significant effects on density and biomass of barnyard grass and also paddy and biological yield of rice. Generally, this highest seed yield was obtained in weed control using Shafagh cultivar (6344 kg.ha-1) and water level of 12 cm Shafagh cultivar (6074 kg.ha-1) while, the lowest seed yield was in the 5cm level of water Tarrom cultivar (3693 kg.ha-1). As a whote it could be concluded, water depth treatment of 12 cm Shafagh cultivar, were identified as the most appropriate treatment.

To evaluate the effects of wheat (Triticum aestivum) and oilseed rape (Brassica napus) strip intercropping on yield components, seed and biological yields of oilseed rape, field experiments were carried out as factorial based on randomized complete block design with three replications at Research Farm of Tabriz University, Tabriz, Iran during 2010-2012 cropping seasons. The first factor consisted of four types of wheat and oilseed rape cropping system, sole crop of oilseed rape (A1),: strip intercropping with 8:3 (A2), 12:4 (A3) and 16:5 (A4) of wheat and oilseed rape rows, respectively and the other factor consisted of two fertilizer levels, B1: 100% chemical fertilizers (urea and triple superphosphate) and B2: 50% chemical fertilizers biofertilizers (Nitrazhin and Barvar2). The results showed that strip intercropping of wheat- oilseed rape resulted in significant increase in yield components, seed yield per occupied unit area and biological yield per occupied unit area of oilseed rape as compared with mono-cropping. The number of silique per plant in intercropping systems was significantly higher than that of mono-cropping. The highest seed yield was obtained in the 16:5 rows of wheat-oilseed rape with 343.76 g.m-2 and the lowest mean was observed in mono-cropping of oilseed rape with 260.21 g.m-2. Biological yield per occupied unit area and seed yield per intercropped unit area in B1 were significantly greater than that of B2, but this treatment had no significant effect on the other traits. Because, B1 and B2 had no significant difference in seed yield per occupied unit area and due to the importance of reduction in chemical fertilizers consumption and food and environmental health care, strip intercropping of wheat-oilseed rape under 50% chemical fertilizers biofertilizers can be recommended as a suitable cultural method.

In connection with sustainability of agriculture the effect of biological and mineral phosphorus fertilizers together with spraying plants with microelements on yield and yield components of pinto bean was investigated in an experiment at the Research Station of Rahal Agricultural College in Khoy city in 2012 growing season. The experiment was used factorial based on randomized complete block design with three replications and two factors. The first factor consisted of phosphorus fertilizer in four levels (without using of fertilizer, as ontrol; barvar-2-phosphate biofertilizer, barvar-2phosphate biofertilizer together with super phosphate at the rate of 100 kg.ha-1 and only super phosphate at the rate of 200 kg.ha-1) and Second factor consisted of micro element spraying of plants with liquid fertilizer in three levels (without spraying, as control; micro element spraying with concentration of 2% and micro elements spraying with concentration of 4%). The results showed that phosphorus fertilizers, affected except number of grains per pod and 100 seed weight, the plant height, number of main branches per plant, number of leaf per plant, number of pods per plant, harvest index and grain yield significantly. Maximum grain yield were obtained from treatments of super phosphate at rate of 200 kg.ha-1 and barvar-2 phosphate biofertilizer together with super phosphate at rate of 100 kg.ha-1. However, the yields of these two treatments were statistically the same. Therefore, reduce use of chemical fertilizers and protect of natural resources, the use of barvar-2 phosphate biofertilizer is advisable. The effect of spraying plants with micro elements on traits, except number of grains per pod and 100 seed weight, like plant height, number of main branches per plant, number of leaf per plant, number of pods per plant, harvest index and grain yield were significant. Maximum grain yield was also obtained from spraying plants by micro elements with density of 2% and 4% and these two experimental treatments were placed in the same statistical group.

To investigate the effect of Trichoderma harzianum, as a bioabsorbant to ameliorate the harmful effects of cadmium (Cd) on growth and yield of barley (Hordeum vulgare L. variety ‘Sahra’), a factorial pot experiment based on completely randomized design with three replicates was conducted. Trichoderma harzianum withtwo levels (with and without inoculation) and cadmium nitrate with four levels (0, 50, 100 and 150 mg.L-1) were the treatments. Results of ANOVA revealed that there was a significant interaction between Trichoderma and cadmium nitrate in terms of biological yield, straw yield, harvest index, spike number per plant and seed number per spike. Mean comparisons showed that Trichoderma inoculation at all Cd levels significantly improved both biological and straw yields. Trichoderma at 50 and 100 mg.L-1 of Cd also increased the spike number per plant (up to 120 and 66%, respectively) significantly. Increasing Cd levels decreased seed yield (19%), 1000 seed weight (18%), partitioning coefficient (57%) and tolerance index (23%) significantly. Inoculation of Trichoderma into growth medium had a significant effect on seed yield and tolerance index (up to 17 and 22%, respectively). In conclusion, Trichoderma harzianum inoculation at lower concentrations of Cd (50 and 100 mg.L-1) could be effective to improve growth parameters of barley plant.

In order to study the effect of different levels of irrigation and different rates of A200super absorbent on dry leaf yield of tobacco burley21, a factorial experiment with four replications was conducted in RCB, during crop season of 2010. The levels of irrigations )80, 120 and 160 mm evaporation from A pan( and four levels of super absorbent (0, 5, 10 and 15 g.m-1). Increasing irrigation interval length from 80 to 160 mm evaporation from pan decreased plant height, dry leaf yield and total income by 13, 10 and 15%, respectivly. Application of 5, 10 and 15 g.m-1 of super absorbent compared to control increased dry yield of leaf by 4, 7 and 10%, and total income by 7, 8 and 13%, respectively. Results also showed that application of 1 kg of super absorbent (costed at least 120000 toman/kg) increased total income by 2580 toman. In general, delayed irrigation decreased quantity and income of tobacco. On the other hand, application of super absorbent increased quantity, quality and income of tobacco as compared to the control treatment, since super absorbent is expensive, its application would not be economical and it is thus not recommended.

Drought is one of the most important environmental stresses that highly affect crop growth and yield. But the response of crops to stress depending on the timing of crop growth stages is different. The purpose of this study was to investigate effect of different levels of water stress (irrigation after 50, 80, 110, 140 and 170 mm evaporation from pan) on different stages of Amaranth growth (establishment, branching, flowering and grain filling). To find the effects of water deficit stress on this plant it was decided to determine its protein percentage, oil and grain yields under drought stress. Evaluation of physiological characteristics as to the extent of osmotic adjustment and antioxidant activity was also carried out. Results showed that water deficit stress,depending on the severity and duration of stress, caused a reduction between between a minimum of 10 to a maximum of 89 percent in yield, 28 to 70 percent in harvest index, 12 to 32 percent in grain protein and 29 to 97 percent in oil yield. This indicates the high sensitivity of grain and oil yields to severe and prolonged drought stresses. Changes in osmotic substances (proline and soluble carbohydrates) showed that this crop under water stress conditions increased proline and soluble carbohydrates by 31 and 50 percents, respectively. Thus, if could be said that under severe droughts the ability of crops to cops with drought will be reduced. Similarly, amaranth, to cope with water stress, increases the amount of antioxidant enzymes like catalase, peroxidase and super oxid dismutase up to 53, 23 and 79%, respectively. Higher amount of super oxid dismutase enzyme produce as the result of drought stress may play an important role to cope with reactive oxygen species and oxidative stresses.

To evaluate the effects of drought and salinity stresses on some germination characteristics, contents of photosynthetic pigments and antioxidant enzymes (CAT, APX and GPX) in the leaves of safflower, a factorial experiment based on CRD was conducted during 2012 at both laboratory and greenhouse of Zabol University with four replications. To expose the plants to drought (0, -6 and -8 bars) and salinity stresses (5, 10 and 15 ds.m-1) PEG 6000 and NaCl were used respectively. The results indicated that the effects of factors on germination percentage and rate, chlorophyll a and b contents and antioxidants enzymes activities were significant. The result of laboratory study revealed a reduction in percentage and speed of germination when plants exposed to negative osmotic potential. Photosynthetic pigments of plant leaves grown in greenhouse significantly decreased by increasing drought and salinity stresses. Increasing drought stress along with soluble salts changed the activity of some antioxidant enzymes. Enzymes’ activity of both CAT and GPX were increased when the plants expose to PEG drought stress, but decreased against the levels of salt stress. APX activity also increased due to drought stress. Interactive effects of drought×salinity stresses indicated that under lower stress GPX enzymes increased salinity, and under severe stress APX was highly increased. It means the production and activity of plant defensive system like these enzymes in recent tensions and leads to protect or make plants tolerate against oxidative stress induced by drought and salinity.

To study the effects of seed priming on Phenological and morphological characteristics of different lentil genotypes (Lens culinaris L.) under rainfed and supplemental irrigation condidions, a field experiment was conducted at the Research Field of the Faculty of Agriculture, Ilam University in 2011–2012. The experiment used was a split- factorial based on RCBD with three replications. The main plots were allocated supplemental irrigation and rainfed conditions and sub plots to the factorial of different lentil genotypes (Gachsaran, Kimia, ILL6037, landrace) and seed priming treatments (Control, hydro, Kinetin, KNO3, PEG 8000). The results showed that genotypic effects, on almost all characteristics were significant at 1% probability levels. The triple interaction was significant at 1% probability levels fornumber of leaves and number of secondary branches, number of flowers and number of dried flowers per plant and also plant dry weight. Seed primings of landrace genotype with KNO3 for morphological characteristics and ILL 6037 with this chemical for seed yield under rain-fed conditions were the best treatment conbinations.

This study was conducted to investigate the effects of different concentrations of ascorbic acid (0, 10 and 20 mM) on growth, fresh and dry weight of basil under different levels of arsenic (0, 40, 80 and 120 mg.kg-1 of soil) in pots. The experiment was factorial based on a randomized complete block design with three replications. It was carried out in greenhouse at the Faculty of Agriculture, University of Zabol. All growth characteristics, fresh and dry weight of shoots and roots and photosynthetic pigments of plants treated with arsenic decreased. Application of ascorbic acid, especially at concentration of 20 mM, could increase the amount and activity of photosynthetic pigments in basil which resulted, in reducing the negative effects of arsenic and an increase on leaf area, fresh and dry weight of shoot as compared with those of control (non-application of ascorbic acid). Foliar application of ascorbic acid did not have significant effect on plant height, fresh and dry weight of roots and leaves as compared with those of the control.

Proper management is required to increase yields of Vigna radiata. To evaluate the effect of different levels of organic fertilizers and date of planting on the yield of two varieties of Vigna radiata, a split plot factorial experiment was carried out on randomized complete blocks with three replications in a field located in Ali-Abad Katoul in growing season of 2013-14. Experimental factors consisted of organic fertilizer at four levels, 1– control, 2– compost (10 tons in hectare), 3– manure (30 tons in hectare), and 4– combined use of manure and compost (20 tons per hectare), two varieties (native to Ali-Abad Katoul and improved VC) and three planting dates (June 11, July 1, July 21). The results showed a significant effect of planting date on the leaf area, total dry weight, shoot dry weight, leaf dry weight, stem length at 1%, and the same effect on the root penetration in the initial growth stage of the plants (seedlings) and 5% levels of probabilities respectivly. The application of organic fertilizers (compost, manure, and a compost and manure mixture) had a significant effect on the plant height and root depth at the 5% level of probabilites. Al together, the local Ali-Abad Katoul variety grew better than the VC variety. We conclude that the environment compatibility of variety, proper planting dates and use of organic fertilizers, especially mixed with manure compost, can have a positive effect on Vigna radiata growth.