نشریه پژوهش های علوم کشاورزی پایدار
سال دوم شماره 4 (پیاپی 8، زمستان 1401)

In order to investigate the effect of different drying methods on the drying time, the amount of essential oil and the essential components of peppermint medicinal plant, two experiments were carried out separately based on a completely randomized design with three repetitions. The results indicated a significant effect of different drying methods on the studied traits. In simple drying, the maximum drying time (570 minutes) was related to samples dried in a cabinet dryer, and the minimum drying time (5.03 minutes) was related to samples dried with 900 W microwave, while in combined drying, the maximum The drying time in the shade treatment was 520 minutes and the minimum time was 5.94 minutes for the 450W + shade microwave treatment. the maximum essential oil contente (2.6%) in simple drying obtained from cabinet dryer, while in the combined drying the maximum essential oil contente in the shade method with 2.4% and combined microwave 100W + shade treatment with 2.3%. in the simple drying method, the maximum amount of Menthol reach at microwave dried sample, while in this way a significant decrease was found Menthone, also in the combined drying, the maximum amount of Menthol reach at shade+ microwave 300 watts, but in this way, the amount of Mentone was significantly reduced. Therefore, it can be concluded that in simple drying, the cabinet dryer method and in combined drying, the shade method, are more favorable than other methods due to the preservation of essential oil.

Drying is the most common way to preserve medicinal plants and protect their biochemical compounds. In order to investigate the effect of different drying methods on some phytochemical properties of Mentha piperitae, including the content of total phenolics, total flavonoids, flavon and flavonol, and also antioxidant activity and total carbohydrates, two experiments were conducted separately based on a completely randomized design with three repetitions. The results showed a significant effect of different drying methods on the studied traits (p<0.05). In simple drying, the maximum amount of total phenolics, total flavonoid, flavone and flavonols related to fresh sample, while the minimum amount of these compounds was obtained in oven treatment with a temperature of 70oC, but in the combined drying method, the maximum amount of total phenolics, total flavonoid and flavon and flavonol were found in the combination treatment of shade + microwave 450 W, and the minimum amount was observed in the microwave drying method of 100 W + shade. Also, in the simple drying method, samples dried in artificial shade with 88.83% and in combined drying with treatment shade + 450 W microwave with 0.48% had the maximum antioxidant activity. Therefore, it can be concluded that in the simple drying of the fresh sample and in the combined drying of the shade + 450 W microwave method, they will be very favorable because they will maintain the biochemical characteristics.

In this research, the spatial distribution of nitrogen, phosphorus and potassium on agricultural lands in Jolge Rokh, Torbat-e-Heydarieh county, Khorasan-e-Razavi province was evaluated using the Geo-statistics. Thus, over 100 soil samples were collected from fields. The values of these parameters were measured for each sample in the soil lab. Evaluation criteria in this study were the mean absolute error and the second root mean square of the residual error using the mutual evaluation validation method. variogram the draw for all elements. After estimating semi variogram model, the validation of the fitted pattern was done by estimating the error. After approving the Variogram, the Kriging interpolation function was applied to map the distribution of the nutrient elements in the study area. Our results revealed that the nutrient elements had different spatial distribution in the plain. The percent of soil organic carbon in 90% of the study area was lower than the critical limits of nitrogen and the values of available Phosphorous and potassium were respectively in 32.2% and 46% of the lands were higher than the critical limits of nitrogen. In general, mapping nutrient elements distribution by Geo-statistical procedures is known as applicable tool in demonstrating the deficiency or excess of the nutrient elements in soil and optimizing fertilizers consumption in plants nutrition.

The biochemical traits of different maize varieties under leaf and cob defoliation conditions were investigated in a factorial experiment a randomized complete block design with three replications in Shiraz-Zafarabad during two crop years of 2017-18 and 2018-19. Treatments consisted of removing leaves and a part of the cob at three levels of no remove (control), removing half of the cob after pollination, and removing two upper and lower leaves of the cob after pollination as. The second factor comprised seven maize varieties including SC704, Kansor, Kordona, Karaj 703, Koosha, Fajr, and Danial 690. After preparing the substrate in the first and second years, seeds of different varies were planted in the plots based on the treatments. Leaf and cob defoliation treatments were applied after pollination. The results showed that the highest contents of chlorophyll a (98.46 mg/g fresh weight, FW), chlorophyll b (138.7 mg/g FW), carotenoids (74.33 mg/g FW), and anthocyanin (1.915 mg/g FW) were obtained in the SC704 variety under combined treatment of defoliating two upper and lower leaves of the cob. The highest amount of catalase (58.73 mg protein/min) was recorded in Fajr variety in the control, but peroxidase (173.4 mg protein/min) and polyphenol oxidase (64.7 mg protein/min) activities were uppermost in the Koosha variety of the control treatment. The varieties of S.C.704, Fajr and Kosha were the best variety.

In order to study the effects of water deficit stress on two safflower cultivars under spring and summer sowing conditions, an experiment was conducted in a split-split-plot layout based on a randomized complete block design with three replications in 2017 at the research farm of agriculture faculty, Islamic Azad University, Sanandaj Branch. The main factor was the sowing date including spring and summer dates. The sub-factor was drought stress with two levels (full irrigation and interrupted irrigation at the flowering stage). The sub-sub-factor was cultivar including Sina and Faraman. The heads number per plant and seed yield in spring sowing significantly increased compared to summer sowing. In spring sowing conditions, yield and its components were significantly decreased as the result of water deficit stress during the flowering stage compared with full irrigation however in summer sowing conditions, stress had no effect on the above-mentioned traits. The highest rate of seed yield (3287 kg/ha) was obtained in the spring sowing of Faraman cultivar with full irrigation, and there was no significant difference between the two cultivars with respect to seed yield, under stress conditions in spring or summer sowing conditions. According to the results of this experiment, in summer sowing conditions there were no advantages from irrigation at the flowering stage compared with interrupted irrigation at the flowering stage, therefore in the case of shifting the sowing time from spring to summer, it will be possible to save the water by interrupting the irrigation at flowering stage accordingly an acceptable yield may be attained as a second crop.

Rice is one of the most important and oldest crop and is one of the three leading crops in the world. Chilo suppressalis (Walker), rice striped stem borer, is a key insect pest damaging the rice crop up to 33 percent. Understanding genetic structure of the pest is essential for an effective pest management program and can corporate with control program. Aim of this stud was to determine the genetic structure of mitochondrial COII (mtDNA-COII) gene of the pest in north of Iran. Rice stem borer specimens were collected from rice fields in Guilan and Mazanderan provinces, at Caspian Sea coast at seasonal activity (spring) in 2016-2017. Genetic structure of 18 populations of the species was invesigated using polymerase chain reaction (PCR) followed by direct-sequencing of mtDNA-COII gene. The obtained sequences were compared with each other and the available data in GenBank database. In total, 312 and 676 specimens were collected from Guilan and Mazanderan provinces respectively. Results showed that all specimens from two provinces are identical are like specimen from South Korea with GenBank ID MK207057.

In order to investigate the effect of gibberellic acid, magnetic field and temperature on strawberry, this research was conducted in form of split plot on based of randomiz completely design and treatments include gibberellic acid, magnetic field and temperature stress in three levels. The results of analysis of variance of the data showed that the interaction effect on all studied traits was significant. The comparison of the averages showed that the highest amounts of chlorophyll a (14.95 mg of protein per minute) and total chlorophyll (28.54 mg of protein per minute) in the treatment of 100 mg/L gibberellic acid, magnetic field of 10 millitesla and temperature of 2 degrees and the highest of chlorophyll b (9.26 mg of protein per minute) and polyphenol oxidase enzyme (57.52 mg of protein per minute) were obtained in the treatment of 50 mg/L of gibberellic acid, 10 milliTesla magnetic field and 8 degrees. The highest amounts of peroxidase (53.6 mg of protein per minute) in the treatment of 100 mg/liter of gibberellic acid acid, magnetic field of twenty millitesla and temperature of twenty degrees Celsius and the highest values of titratable acidity (0.89 percent) and pH (6.9) were obtained in the treatment of no use of gibberellic acid, no use of magnetic field and temperature of 20 degrees. In terms of the triple interaction effect, the best effective treatment on increasing the storage time of strawberries was the combined treatment of 50 mg/L gibberellic acid and 10 milliTesla magnetic field and 8 degrees Celsius temperature.