مجله به زراعی کشاورزی
سال بیست و سوم شماره 2 (تابستان 1400)

The phenomenon of reduced potato yield have increased in recent years under adverse conditions, such as water stress. The effects of water stress on yield and yield component of three potato cultivars have been evaluated in this study during 2019 growing season. This investigation has been arranged as split-plot experiment, based on a randomized complete block design with three replications at Rozveh Agricultural Research Station (Chadegan, Isfahan, Iran). The main-plots are assigned to irrigation levels (75% and 100% field capacity) and sub-plots to potato cultivars (Marfona, Agria, and Atousa). To ensure the initial establishment of the plant and prevent severe crop failure, one additional irrigation has been performed at the establishment stage, with two supplementary irrigations performed at the tuber initiation stage for all plots. There has been a significant interaction between irrigation level and cultivars for tuber yields (α<%1) as well as other traits (α<%5). In water stress conditions, yield and water use efficiency of Atousa, new cultivar, are more than the other cultivars. Marketable yield of Atousa cultivar is about 40% higher than Marfona and Agria cultivars. The new cultivar produces 6.53 kg of tubers per cubic meter of water, while water use efficiency for Marfona and Agria is only 4.82 and 5.02 kg m-3, respectively. In conclusion, it is suggested that Atusa cultivar in both water stress and in normal conditions is more suitable for cultivation in the study area than in Marfona and Agria cultivars.

Yield gap analysis is a quantitative estimate of possible increase of the capacity to provide food for a specified area. It is an important component for designing strategies to supply food on a scale of regional, national, and global level. In this regard a study has been conducted to determine the extent and function of chickpea and lentil crop vacancy distribution at Gorgan University of Agricultural Sciences and Natural Resources during 2016-2018. Using SSM-iCrop2 model, the study simulates potential yield in chickpea and lentil producing regions in Iran. For this purpose, it employs the protocol of Atlas Gap Project, called GYGA protocol, to identify climatic zones and identify important meteorological stations, located in chickpea and lentil production areas in the country. After identifying the important stations, the performance potential for the station range is simulated and then the regional results are generalized to the whole country, based on the GYGA protocol. For dryland chickpeas in the country, the values of actual and potential yield as well as yield gap have been 0.43, 1.04, and 0.61 tons per hectare, respectively. In case of rainfed lentils in the country, the values of actual yield and potential along with yield gap have been 0.43, 1.10, and 0.67 tons per hectare, respectively. The present study can be used for better management in low-yield and high-yield areas of the country for these two products.

To study the effect of nitrogen fertilizer and irrigation regimes on some crop growth indices of forage maize under conventional and conservation tillage system, an experiment has been conducted in split plots with a randomized complete block design and three replications at University of Tehran’s farm during 2018. Tillage systems, as the main plot in two factors, include conversation and conventional tillage, whereas water stress, being the subplot, is in three levels which are 30%, 60%, and 90% of moisture requirement. Also, nitrogen fertilizer, as the sub-sub plot, is at three levels, 0, 50%, and 100% of the recommended rate. Results in the flowering stage show that the highest leaf area index (6.28) and crop growth rate (34.01 gr m-2 day-1) have been obtained from the interaction between slight water stress (90% of crop water demand) and nitrogen (100% of crop demand) as well as the interaction between slightly water stress and 100% nitrogen in conventional tillage, respectively. The highest relative growth rate (0.08 gr gr-1 day-1) and total dry matter (1006.86 gr m-2) belong to simple impact of 100% nitrogen along with the interaction of slightly water stress and 100% nitrogen in conventional tillage, respectively. Results show that under severe water stress and higher application of nitrogen, the fertilizer will cause less crop dry matter under conventional tillage.

In order to investigate the role of foliar application of yeast extract on physiological and Biochemical properties of cowpea (Vigna sinensis L.) under drought stress conditions, a factorial experiment has been conducted as a randomized complete block design with three replications in Agriculture Campus of Shahrood University of Technology (located in Bastam) during 2017 under drought stress and foliar application of yeast extract. Drought stress involves two stages of 50 present flowering and 50 present pod formation with control treatment (without irrigation interruption). Foliar application of yeast extract (two, four, six g/L, and control) are repeated twice with a seven-day interval, with the first one being 30 days after planting. Results show that drought stress has decreased relative water content of leaves. In contrast, relative water content (5.82%), proline content (30.74%), leaf flavonoid (83%), nitrogen (3.82%), phosphorus (22.22%), and potassium (43%) are among the traits that have increased with the use of yeast extract, compared to the control. Six g / L of the yeast extract has increased grain yield (1.02 t ha-1), leaf anthocyanin (0.072 mg /g fresh weight), and proline (31.62 mg /g fresh weight). It can be said that a concentration of six g/L of yeast extract can be useful to reduce the severity of drought stress. The yeast extract can act as an ecological strategy to improve the defensive response against environmental stresses.

Studies to assess quality of dent maize grain are noteworthy because of its wide use as food, feed and ethanol production. This study aimed to evaluate the concentration and composition of starch and oil in maize grain in response to different cultivars (KSC704 and KSC260), planting dates (20 June and 21 July), irrigation (12-day and 6-day intervals) and nitrogen (0 and 184 kg N ha-1) rate as the strip-plot factorial statistical model during the 2018 growing season in Pakdasht county of Iran. The results suggested that nitrogen application increased grain yield by one tonnes ha-1. In addition, KSC260 had higher grain yield than KSC704 by 0.96 tonnes ha-1. All compositional variables except stearic acid were affected by the interaction effect of irrigation and nitrogen rate. In low irrigated treatments, nitrogen application reduced the amount of oil, palmitic acid, oleic acid, linoleic acid and linolenic acid. In low irrigated condition, nitrogen application had no effect on increasing the concentration of starch and amylopectin. The use of nitrogen fertilizer reduced the amount of stearic acid by 0.05 g kg-1. In conclusion, the balance between irrigation and nitrogen utilization seems to be important for improving the oil and starch properties of maize grain.

In order to investigate the effect of barley cultivars on the yield and yield components of grain under rain-fed conditions a factorial experiment has been carried out in a randomized complete block design with four replications at Gonbad-e Kavous University Research Field during 2016 – 2017 and 2017 – 2018 growing seasons. Density treatments of 200, 300, 400, and 500 grain per square meter have been considered as the first, and four barley cultivars, namely Fardan, Khorram, Mahoor, and Sahra, have been taken as the second factors. In case of the number of grains per spike and the number of spikes per square meter, Sahra cultivar in minimum density and Mahoor cultivar in maximum density have proven to be the best cultivars, respectively. The highest thousand grain weight belongs to Fardan cultivar. Maximum grain yield in first and second year of the experiment have been obtained from Mahoor cultivars with 300 grains in meter square and Khorram with 200 grains in meter square, respectively. Higher yield in the second year than the first one seems to be due to higher rainfall and more appropriate distribution, especially in the reproductive stage and grain filling period. In both years, a negative and strong correlation is observed between the number of spikes per square meter and the number of grains per spike (r=-0.67 and r=-0.83 in the first and second year, respectively); but this correlation has been positive with grain yield. The highest positive and significant correlation belongs to the one between grain yield, harvest index, and biological yield. According to the results, an increase in grain yield is due to the increase in both harvest index and biological yield. Finally, optimum density for maximum grain yield has been 200 grain in meter square for Fardan, Khorram, and Sahra; and 300 for Mahoor.

In order to investigate the interaction between sodium nitroprusside and drought stress on photosynthetic pigments and their relationship with yield and yield components of rapeseed, an experiment was conducted during two cropping years (2015-16 and 2016-17) at Hamedan Agricultural and Natural Resources Research Center. The experiment was carried out as a factorial in randomized complete block design with three replications. Experimental factors were irrigation levels including full irrigation (control), irrigation termination from beginning silique stage and irrigation termination from grain filling stage, and four treatments of foliar application of sodium nitroprusside with concentrations of 0, 100, 200 and 300 μM. The results showed that irrigation termination significantly reduced the amounts of studied traits. Sodium nitroprusside foliar application increased the amounts of photosynthetic pigments, yield and grain yield components under drought stress and non-stress conditions. The highest and the lowest grain yield were obtained in the combination treatments of plant foliar application with 300 mM sodium nitroprusside and full irrigation (5129 kg/ha) and non-foliar application and irrigation interruption at the beginning silique stage (3396 kg/ha), respectively. The experiment indicated that sodium nitroprusside application can have positive effects on photosynthetic pigments, yield components and grain yield of rapeseed under drought stress and non-stress conditions, and therefore its application can greatly mitigate the adverse effects of drought stress in water deficit conditions.

To investigate the effect of seed priming on emergence characteristics, root morphological growth, and phenological trends of rice in direct seeding, an experiment has been conducted in Sari Agricultural Sciences and Natural Resources University within 2019. The study is conducted as factorial in a randomized complete block design with three replications. The factors include Tarom Hashemi and Shiroudi cultivars and priming at five levels, namely hydropriming (for 48 hours), calcium chloride, and potassium chloride priming (Ψs -1.25 MPa), ascorbate acid (10 mg l-1), and control (no priming). The effect of priming on emergence percentage shows that the highest amount of this trait belongs to 90% in priming with calcium chloride, which is not significantly different from priming with potassium chloride and water. The rate of emergence of priming with calcium chloride, potassium chloride, and water has increased by 50%, 36%, and 29%, respectively. Results show that priming with calcium chloride, potassium chloride, ascorbate acid, and water has increased by 55%, 50%, 33%, and 38% of the plant height and by 48%, 29%, 12%, and 25% of plant dry weight, respectively. In Shiroudi and Tarom Hashemi cultivars, the time required for the onset of tillering has been 27.40 and 24.53 days; panicle appearance, 90.4 and 53.87 days; flowering, 100.53 and 70.87 days; and maturity 132.26 and 94.61 days, respectively. The least time required for panicle appearance and flowering is observed in priming with calcium chloride, although this has not been significantly different from other priming, and decreased by 11.17 and 7.5 days to the control, respectively.

In order to evaluate the increment possibility of safflower seed yield and oil percentage through the application of cytokinin, a split factorial experiment has been conducted based on randomized complete block design with four replications at the research farm of Agriculture Faculty, the University of Zanjan, during the 2018-2019 and 2019-2020 cropping seasons. In this experiment, irrigation levels include optimal irrigation and drought stress to main plots and safflower cultivars, namely Sina, Faraman, Parnyan, Gholdasht, and Mahaly Esfahan, and three levels of cytokinin (6-Benzyl Aminopurine), including non-application (control), 50, and 75 μM,  have been allocated to subplots as factorial. At the flowering stage, simultaneous with applying drought stress, safflower plants havee been sprayed with 6-Benzyl Aminopurine. Results show that drought stress has decreased yield components, seed yield, biological yield, harvest index, oil percentage, and oil yield and the application of cytokinin minimizes the negative impacts of drought stress, while boosting the above traits. The highest seed yield has been obtained from applying 75 μM of cytokinin, with an increase of 30.7% compared to the control. Also, among the studied cultivars, the Mahaly Esfahan cultivar under optimal irrigation with an average of 36.09% shows a higher oil percentage, compared to other cultivars. Therefore, the use of cytokinin can be suggested as a solution to decrease the negative effects of drought stress and enhance seed yield and oil percentage of safflower under optimal irrigation and drought stress conditions.

Due to hot and dry climates of South Khorasan province, it is quite vital to choose the suitable crop and planting date. In this condition, pearl millet nutrifeed hybrid (Pennisetum americanum var. nutrifeed) can be a valuable forage in rotation with other plants. This experiment is carried out in 2017-2018 in strip split plots design in time in Azad University research field, Birjand. The treatments include 4 sowing dates (April 8, April 28, May 18, and June 7), 3 irrigation regimes (providing 100%, 75%, and 50% of the plant’s water needs based on the plant potential evatranspiration), and two cuttings in a completely random blocks design with three replications. The highest water use efficiency is observed when providing 50% of water needs on April 8, along with the first and second cuttings. Following the delay in planting date from April 8 to June 7, the forage dry matter yield of millet decreases by 24.4% when it is supplied with 100% of its water needs. This decrease is 24.2 and 46.9, in case of supplying 75% and 50% of water needs, respectively. Therefore, by supplying 75% of pearl millet water needs and planting it on April 8, with a 25% reserve of water consumption, the dry matter yield is acceptable.

The effect of water deficit stress has been evaluated on oil quality and yield of 11 sunflower hybrids in Karaj during 2012 and 2013. Three separate experiments have been carried out as the base of randomized complete block design with three replications to apply water deficit stress treatments. Irrigation of control, mild, and severe stress treatments are performed on the base of 60, 120, and 180 mm evaporation from Class A evaporation pan, respectively. Results show that seed yield has decreased about 18% and 33% in mild and sever water deficit stresses, respectively. Yield and oil percentage are affected by hybrids and the interaction of year and stress. Barzegar hybrid, with an average of 2846 kg/ha, has had the highest grain yield. It is also in the top group with 43.65% oil. Yield and seed oil percentage are affected by environmental conditions of years, while water deficict stress has no significant effect on oleic and linoleic acids. However, there is a strong negative correlation between oleic and linoleic acids. Hysun 25 and Sirena cultivars are suitable for oil production with higher oleic acid and Barzegar and G6×R-43 are suitable for oil production with higher linoleic acid.

Value of Cultivation and Use (VCU) trial of some new cotton genotypes and cultivars have been performed at Tehran province agriculture and natural resources research and education center at Varamin, based on complete randomized design by four replications during 2016 and 2017. Evaluated cotton genotypes and cultivars include 1) Varamin (control), 2) Khordad (control), 3) Ulran (commercial cultivar), 4) 43259 genotype, 5) A-SJ2×349 genotype, 6) R7 genotype, 7) no. 210 genotype, 8) no. 221 genotype, 9) Leon (foreign commercial cultivar), and 10) Sajedi (new cultivar). Results reveal that Sajedi new cultivar is the earliest cultivar in both years in comparison with other studied genotypes and cultivars. It also has had the most boll number and weight and its seed cotton yield has been in the same statistical group of the highest seed cotton yield control cultivars. The highest lint percentage and fiber elasticity in first year belongs to this cultivar. Therefore, Sajedi new cultivar can be introduced and commercialized for cultivation in Tehran province as well as similar Vatamin regions.

The present experiment has been carried out as a split plot based on randomized complete block design with three replications in Safiabad Agricultural and Natural Resources Research and Education Center of Dezful between 2012 and 2014. The main plots is consisted of 3 sowing dates (November 5, November 25, and December 15) with the sub plots including 10 levels of foliar application (100, 200, 300 mg.lit-1 ascorbic acid, 100, 200, 300 μmol ascorbic acid, 10, 20, 30 vol% methanol, and the foliar application of distilled water as control treatment). The effect of sowing date and foliar application as well as their interaction has had significant effect on proline, soluble sugars, number of siliques per plant, and seed yield (P≤0.01). Comparing means of sowing date × foliar application shows that the maximum number of siliques per plant (68.96) has been formed in the first sowing date with the foliar application of ascorbic acid (300 mg.lit-1). There has been a significant difference between different sowing dates: the seed yield has decreased in the second and third sowing date, compared to the first one by 145% and 30%, respectively. However, foliar application of experimental treatments has increased the seed yield in all sowing dates, but it is recommended to use ascorbic acid (300 mg.lit-1) in the first and third sowing dates as well as salicylic acid (200 µmol) and methanol (10%) in the second sowing date.

In dry regions, root systems play a major role in controlling plant growth and yield, thanks to their importance in water absorption. In order to investigate the effect of irrigation regimes on root and shoot traits of sesame (Sesamum indicum L.) genotypes, a field experiment has been conducted in Karaj, at Seed and Plant Improvement Institute, during 2017 and 2018. A factorial experiment has been laid out in a completely-randomized design with four replications. This study deals with five genotypes of sesame in two irrigation regimes, including full and low (drought stress) irrigation treatments in terms of root and shoot-related traits. Results show that there have been significant differences between genotypes and irrigation regimes for root and shoot traits. In all genotypes, root length density is higher in full irrigation treatment as well as the upper soil layer (0 to 30 cm deep), compared to stress treatment. In addition, under drought stress conditions root depth increases (by 30% in average) in all genotypes. In contrast, root dry weight has decreased in Dashtestan 2 (15 %), Darab 1 (16 %), and Naz (22 %), and increased in Oltan (1 %), USA-ns 96 (7 %), and Sodan 94 (10 ) genotypes. On the other hand, the highest amount of shoot dry weight belongs to the USA-ns 96 genotype (39 g), and the lowest to Naz cultivar (22 g). Finally, results show that USA-ns 96 genotype, being superior in terms of root characteristics such as root depth and root length density compared to other genotypes, in addition to having more shoot dry weight, show the least dry weight loss under stress conditions.

Pink stem borer, Sesamia creticaLed, is one of the most important pests of sugarcane and maize in Iran. Insecticidal properties of essential oils of four cumin ecotypes, namely Fars-Sivand (FS), North Khorasan-Shirvan (KS), Kerman-Kuhbanan (KK), and Kerman-Rafsanjan (KR), has been evaluated against 4th instar-larvae of S. cretica in a completely randomized design with four replications. Larval mortality at 27±2 °C, relative humidity of 65±5%, and 16:8 hours light: darkness period is recorded after 72 hours. Results show that all cumin ecotypes have been toxic to the pest, with the lowest LC50 value, obtained from the essential oil of KR ecotype (2725 ppm) followed by KK, FS, and KS ecotypes (2777, 3099, and 8390 ppm, respectively). The chemical analysis of essential oils tested by GC-MS shows that m-cymene in the KR ecotype has been higher than other cumin ecotypes. Therefore, the high toxicity of KS ecotype compared to other cumin ecotypes can be related to the presence of such compounds. According to the present study’s results, the essential oils of cumin ecotypes are potentially a great substitute for chemical insecticides in the integrated management of S. cretica.

Regression models are a tool to quantify the weeds seed germination in response to temperature. In order to determinate the cardinal temperature of four weeds Brassicaceae family (Eruca sativa, Hirschfeldia incana, Sinapis arvensis, and Erysimum repandum), four separate experiments have been conducted at nine temperatures (5, 10, 15, 20, 25, 30, 35, 40, and 45°C) as factorial, based on a complete randomized design (CRD) with three replications in Agricultural Science and Natural Resources University of Khuzestan during 2019. The First factor includes four weeds, and the second factor, weeds’ response to temperature. These have been different at 40°C only. H. incana displays some germination (38%), whereas the germination of other weeds has been completely inhibited. Based on the used models, the best models to determine cardinal temperature for E. sativa has been Beta, five parameter; for E. repandum, Beta, four parameter; and for S. arvensis, and H. incana, Dent-like model. The optimum temperature for germination of E. sativa and E. repandum are predicted to be 19.43 and 16.01 °C (Beta four and five parameter models), respectively. Moreover, the lower and upper optimum temperatures for germination of H. incana and Sinapis arvensis have been achieved at 27.22, 29.26, 23.23, and 27.86 °C, respectively (at Dent-like model). The maximum emergence of Eruca sativa, Hirschfeldia incana, and Sinapis arvensis is expected in November and from December to February for Erysimum repandum. Modeling germination in response to temperature can be considered in weed management, especially when determining the control time of weeds.

Water imbalance and vascular occlusion are two serious factors in sort lasting of cut gerbera. In order to evaluate the potentials of essential oils as an alternative to chemicals in the protective solution, a factorial experiment has been conducted in a completely randomized design with four replications. The treatments contain 8-hydroxyquinoline sulfate (0, 100 ppm) and thyme and savory essential oils (250, 500 ppm). Preservative solutions include distilled water and 8-HQS, both considered as the controls. Every day in a week, in addition to evaluating flower longevity, physiological parameters, plant water relations, and bactericidal population are measured. Results show that the protective solution with 250ppm of thyme essential oil offer 8.6 days longer vase life than the control. The 500ppm savory displays the best performance to protect the petal membrane stability, compared to both controls (distilled water or 8-HQS) at the end of the experiment. Gerbera petals, treated with thyme essential oil at 250 ppm, are fresher, having higher water content than other treatments, even in comparison with 8-HQS. During longevity, anthocyanin and dry matter have had an increasing trend with the Tss, showing a decreasing trend. The antibacterial properties of the essential oils have been significantly established in respect to the desired results of growth controlling of the microbial population in the preservative solution, even compared to 8-HQS, so it seems that the essential oils are a good alternative for antibacterial chemicals and can even reduce the harmful environmental side-effect of conventional preservative.

In order to investigate the effect of nitrogen, phosphorus, and potassium elements on fatty acid profiles, oil percentage, grain yield, and flax seed oil, Lirina cultivar, a factorial experiment has been conducted during 2019, based on a randomized complete block design with three replications in Hashtgerd research farm, Alborz Province.  It has employed a factorial arrangement in a randomized complete block design with three replications with the factors involving three levels of nitrogen fertilizers (N1=30, N2=60, and N3=90 Kgha-1, three levels of phosphorus fertilizers (P1=40, P2=80, and P3=120 Kg.ha-1), and three levels of potassium fertilizers (K1=40, K2=80, and K3=120 Kg.ha-1). Result show that the highest amount of linolenic acid (43.99%), linoleic acid (17.68%), and palmitic acid (6.02%) have occurred in 30 kg. ha-1 nitrogen and 40 kg.ha-1 phosphorus. The highest amount of oleic acid (27.49%) and stearic acid (5.25%) belong to 30 kg.ha-1 phosphorus. Based on the results, the highest amount of grain yield (2384 kg.ha-1) and oil yield (939 kg.ha-1) are recorded in 90 and 120 kg.ha-1 nitrogen and phosphorus, respectively. Therefore, according to the results, different levels of fertilizer on percentage of oil has had no significant effect.