نشریه بوم شناسی گیاهان زراعی
سال پانزدهم شماره 1 (پیاپی 55، بهار 1398)

Sustainability in wheat cultivation systems depends on several components. The current study was conducted to identify and analyze the sustainability components of wheat cultivation system in Gorgan county. The statistical population was all farmers and wheat growers of Gorgan county. Samples volume was estimated through Cochran formula and samples were chosen randomly. Finally, 190 questionnaires were used. The validity of questionnaire was confirmed by the agricultural development experts and the reliability of the questionnaire items was calculated by Cronbach’s alpha coefficient as 0.806. Data analyzed by factor analysis method and in descriptive and analytical parts. There was a significant positive correlation between the main variables such as cultivated area of wheat, integrated pest management and land reform, using modified seeds, number of visits to extension centers, sustainable agricultural knowledge level, job satisfaction from agriculture, profit from wheat cultivation, wheat yield and sustainability factors of wheat cultivation system. In total, five factors of ecological-crop factors, sustainable-oriented crop operation, support-extension services factor, social-collaborative status factors, and economical factor consisting total of 21 variables accounted for about 74% of variance in sustainability of wheat cultivation system in Gorgan county. Improving rural resource management, expanding cooperative and participatory agricultural activities, native knowledge of farmers, policy-makings by extension planners and reducing production. Costs in the exploitation process can play an effective role in improving the process of agricultural stabilization.

Deficit irrigation is a technique for optimizing crop production under drought stress conditions. The superabsorbent hydrogel is a hydrophilic polymer being able to absorb and retain a large amount of water. This study was conducted to evaluate the effect of different rates of Super AB A 200 superabsorbent hydrogel on yield and yield components of corn cv SC704 under drought stress. The experiment carried out in split plot based on a randomized block design in Hamidieh region, Khuzestan province, Iran. In this study, three different depths of irrigation were considered as the main plot including 100, 75 and 50% of water requirement of plants respectively and different levels of superabsorbent were used as sub-plot including 0 (control), 15, 30 and 45 g/m2, respectively. Increasing drought stress led to significant loss of yield, yield components and decrement in water use efficiency of corn The effect of drought stress was determined by decreasing leaf surface area index, disruption of nutrients uptake and transfer, which ultimately led to a decrease in the supply of nutrients, yield and yield components. Finally, it was concluded that superabsorbent hydrogel is effective in retaining water and nutrients and releasing them under drought stress conditions and significantly prevents the decline of yield and yield components. It is recommended to use 75% of plant water requirement and 45 g/m2 superabsorbent for corn cultivation under Khuzestan province climate conditions.

A field experiment was conducted to investigate the effect of zinc and boron spraying on yield and yield components of two spring lentil cultivars in Kermanshah, Iran in a factorial experiment based on randomized complete block design. The first factor consisted of Bilehsavar and Kimia cultivars. The second factor was spraying in four levels consisting of non-spraying, spraying with zinc sulfate at 1.5 o/oo, and boric acid 3 o/oo separated or in combination. The effects of spraying on the all studied traits were significant but except for hundred seed weight and harvest index. Bilehsavar had higher yield than Kimia cultivar. Zinc sulfate spraying also increased seed yield, biomass yield, and harvest index. Boron spraying increased the grain yield and harvest index, while combination of zinc sulfate and boric acid spraying increased number of pods per plant, number of seeds per pod, and plant height in Bilehsvar cultivar. Also, the results of this study were useful in the effect of leaf spraying with micronutrient fertilizers on zinc and boron, which was the most affected by the application of zinc sulfate and boric acid in conjunction with increasing number of pods per plant and number of seeds per pod. Therefore, planting of Bilesavar cultivar and its spraying with both ZN and B fertilizers is recommended in Kermanshah climate condition. A field experiment was conducted to investigate the effect of zinc and boron spraying on yield and yield components of two spring lentil cultivars in Kermanshah, Iran in a factorial experiment based on randomized complete block design. The first factor consisted of Bilehsavar and Kimia cultivars. The second factor was spraying in four levels consisting of non-spraying, spraying with zinc sulfate at 1.5 o/oo, and boric acid 3 o/oo separated or in combination. The effects of spraying on the all studied traits were significant but except for hundred seed weight and harvest index. Bilehsavar had higher yield than Kimia cultivar. Zinc sulfate spraying also increased seed yield, biomass yield, and harvest index. Boron spraying increased the grain yield and harvest index, while combination of zinc sulfate and boric acid spraying increased number of pods per plant, number of seeds per pod, and plant height in Bilehsvar cultivar. Also, the results of this study were useful in the effect of leaf spraying with micronutrient fertilizers on zinc and boron, which was the most affected by the application of zinc sulfate and boric acid in conjunction with increasing number of pods per plant and number of seeds per pod. Therefore, planting of Bilesavar cultivar and its spraying with both ZN and B fertilizers is recommended in Kermanshah climate condition.

To determine the effects of planting date and nitrogen fertilizer on stem borer, blast disease and rice yield of in replanted rice cultivars of Koohsar, Binam, Tarom Hashemi, and Tarom Mahali, two separate experiments were carried out in split plot based on randomized complete block design during the growing years of 2015-2016 in Amol, Iran. The first experiment was the effect of nitrogen fertilizer with the amounts of 30, 60, and 90 kg/ha on rice cultivars. The second one was the effect of planting dates including 24 July, 3, 11, and 13 August on severity of stem borer, blast disease and rice cultivars yield. The severity of stem borer was about 18 on Koohsar, and 6 ~ 12% on Binam, Tarom Hashemi, and Tarom Mahali cultivars. The increase of nitrogen application rate resulted in significant increase of stem borer severity in vegetative and reproductive stages.The amounts of panicle node blast in Koohsar and Binam cultivars were 21 ~ 43 and 4%, respectively. Increasing nitrogen rate caused significantly higher rice yield, but application of 90 kg/ha N increased the severity of stem borer. There was no significant difference in stem borer severity among the studied cultivars. The stem borer and blast disease severity was in maximum level in the first planting date. Panicle node blast severity in Koohsar was more than local rice cultivars in all three planting dates. To obtain higher rice yield and less damage of stem borer and blast disease in rice replanting system, the second  planting date and 60 kg/ha of N fertilizer is recommended.

In this study, the effect of two sodium chloride concentrations of 4 and 8 g/L on two marigold sparse petal and compact petal genotypes evaluated at germination and adult stages using factorial experiment based on randomized complete block design. There were differences between genotypes in some germination indices, vegetative and reproductive morphological and physiological traits.  Some traits were reduced by increasing sodium chloride concentration to 8 g/L in both growing stages.  Interactional effects of salt × genotype were significant on germination percentage and leaf water saturation deficient at seedling and adult stages, respectively. Sparse petal and compact petal genotypes were more tolerant to salinity in seedling and adult stages, respectively. Therefore, cultivation of compact petal marigold genotype in areas with water salinity problem up to 4 g/L NaCl is suitable and advisable.

To investigate the effects of different nitrogen and potassium fertilizer rates on nitrogen use efficiency (NUE), nitrogen uptake efficiency (NUPE), nitrogen utilization efficiency (NUTE) and N, K, P, Ca and Mg nutrient contents in sweet fennel, a factorial experiment was conducted based on randomized completely block design with three replications in University of Zanjan, Iran. The applied fertilizers included 50, 100, and 150 kg/ha of N and K from urea and potassium sulfate sources, respectively. N and K application had significant effect on NUE and N, P, Ca, P, and Mg contents. Increasing nitrogen application rate levels desreased NUE, NUPE, and NUTE. Increasing of K application rate caused increment of N efficiency. Application of N and K fertilizers increased N, K and P concenterations on bulb tissue. Increasing N application rates resulted in more Ca and Mg concentrations, but application of K decreased Ca and Mg contents in bulb tissue. Regarding short growing period of sweet fennel, lower rates of N fertilizer is recommended to improve NUE.

Coneflower is a valuable medicinal plant containing high levels of secondary metabolites, but no suitable method for extraction of the entire RNA has been introduced yet. In present study, four methods of RNA extraction including lithium chloride, RNAX-Plus kit, phenol/SDS and lithium chloride/phenol were investigated. For confirming the quality and purity of RNA, spectrophotometer and agarose gel electrophoresis of 1.5% were used. The high absorption ratio of RNA solution at a wavelength of 260 nM to 280 and 230 nM, observation of ribosomal RNAs and the lack of smear on the gel were considered as criteria for determining samples quality. The highest and the lowest qualities of RNA contained 2.9 μg/100 mg of fresh leaves by phenol/SDS method and 1/2 μg/100 mg of fresh leaves by lithium chloride/phenol method, respectively. Therefore, phenol/SDS method is introducing as the most suitable method for RNA extraction from coneflower.

The green peach aphid or spinach aphid is one of the major pests found in various agricultural crops. Toevaluate the effect of chemical and biological pesticides, the green peach aphid was collected from the spinach field in Miyaneh city, Iran and cultivated in greenhouse conditions. Tarragon essential oilswere extracted by Clevenger apparatus. The pesticidal effect of dimethoate, imidacloprid, pymetrozine, acetamiprid and primicarb in recommendedand , , , reduced doses in separate and combined with 62 ppm of tarragon essential oilsin 2to 12 hours after treatment in greenhouse condition was investigated. FifteenmL of essential oils extracted from 1 kg of plant dry material.All applied insecticidal treatments, tarragon essential oils and combination of reduced doses of chemical insecticides with tarragon essential oils were lethal against green peach aphid. There weren’t any significant differences between the lethal effects of applied chemical insecticides regarding the letality of green peach aphid.The concentration of 62 ppm of tarragon essential oilswas able to compete with the dose ofof chemicals recommended doseinlethal percentage of green peach aphid. The combination of recommended dose with tarragon essential oilsshowed acceptable results for controlling the green peach aphid and was as effective as the recommended dose; therefore, it can be recommended as a safeproducttocontrolthis aphid.