JOURNAL OF CROPS IMPROVEMENT (JOURNAL OF AGRICULTURE)
Year:2020 | Volume:22 | Issue:1 |Papers Count:12

In order to investigate the effect of foliar application of Zinc sulfate and Selenium compounds on reducing the effects of heat exhaustion on two wheat cultivars, an experiment has been carried out in a split factorial experiment, based on a complete randomized block design with three replications at the experimental farm of Shahid Chamran University of Ahvaz during the growing season of 2017-2018. The experiment investigates three factors. The main one includes three planting date (i. e., November 11, December 11, and January 10). The solution type has been used as the sub factor, namely (1) foliar application with tap water (control), (2) foliar application with selenium (4 mg/lit of Sodium Selenate), (3) foliar application with zinc sulfate (0. 04%). Also the third factor includes two wheat cultivars (Chamran and Star). According to the results, late sowing has knocked the grain yield down significantly as can be seen through reduced number of grains per spike as well as 1000-grain weight. Reduction of grain number per spike and grain yield is further decreased when using zinc than other foliar application treatments. Thus, on sowing date of January 20, the number of grains per spike dropped in the foliar application treatments of zinc sulfate by 11. 5%, Selenium by 35. 17%, and in the control by 34. 17%, compared to similar treatments on November 20. Compared to this sowing date, on January 20 the decrease grain yield was 49. 3% in the control treatment and 49. 9% in the selenium one, whereas in zinc sulfate treatment it was 20. 19%. Results showed that among foliar application treatments, zinc sulfate displays less reduction grain yield in both wheat cultivars under heat stress as it improves the number of grains per spike, 1000-grain weight, and grain filling duration.

It is necessary to understand the performance potential and the gap between the actual yields of crops with the achievable function so as to diagnose the limiting factors of performance. The present study has been conducted based on CPA Method in 50 fields of Zavkooh villi (Kalaleh, Golestan, Iran) in 2016 and 2017. The study has measured and recorded all information related to management practices, soil characteristics, and farmer socio-economic status. Furthermore, using stepwise regression, the Comparative Performance Analysis (CPA) Method considers the relation between the variables and yield, with the yield gap rate as well as its causes being estimated to reveal each factor’ s contribution to the creation of the yield gap. Results show that there is a 1818 kg per hectare vacuum between the average real yield (2308 kg ha-1) and the yieldable one (4123 kg ha-1), . Accordingly, the most important factors of yield gap in the region include field size (21. 4%), summer plowing (15%), the time of land preparation and plowing (14. 7%), nitrogen fertilizer (14. 6%), potassium fertilizer (14%), weed density per unit area (10. 8%), seed treatment (8. 1%), and Sub-soiler (1. 4%).

In order to investigate the effects of drying methods (desiccation treatment), heat shock, and osmotic stress treatments on viability of primed seeds from different rapeseed cultivars, an experiment has been conducted in 2017-2018 at the Seed Research Laboratory of Gorgan University of Agricultural Sciences and Natural Resources. In this study, seeds of three canola cultivars, i. e., Dk-xpower, Teraper, and Hayola50, all exposed to priming treatments, undergo desiccation, heat shock, and osmotic stress treatments. Thereafter, to investigate the effects of different treatments, the treated seeds have been subjected to controlled deterioration test. Finally, after fitting the three-parameter logistic model to germination percentage during controlled deterioration test, the time for germination decline to 50% has been calculated and used as the criterion to compare seed viability. Results show that the response of rapeseed cultivars to different treatments have been different. Furthermore, priming methods and different treatments in drying phase of primed seeds, display varied effects on seeds' lifespan. In general, heat shock treatments are found efficient in Dk-xpower and Traper cultivars as they increase seeds' lifespan. In contrast, osmotic stress treatments often have had negative effects on seed viability in all canola cultivars. Even, "osmopriming" and subsequent slow drying of primed seeds have had more negative effects than "hydroperiming", associated with fast drying methods.

In order to evaluate the impact of irrigation, humic acid, and mycorrhiza application on physiological traits, yield, and Water Use Efficiency (WUE) of cotton, an experiment was carried out as a factorial split-plot based on a randomized complete block design with three replications in the research farm of Islamic Azad University of Birjand, Iran in 2016. Three irrigation levels (40%, 70%, and 100% of water requirement or PWR) serve as the main plot and the combination of two mycorrhiza levels (non-application and application) and two humic acid levels (0 and 10 L. ha-1) are the sub-plot. Results show that mycorrhiza application in the conditions of supplying 100% and 70% PWR for the plant significantly increase the chlorophyll index, stomatal conductance, number of boll per m2, and the yield of cotton, but the highest increase in these traits belongs to the condition in which 70 PWR has been supplied. Also, the highest WUE has taken place in 70 PWR and application of mycorrhiza. Generally, mycorrhiza improves physiological traits, yield, and WUE of cotton more effectively than humic. Results show that considering the WUE and economic yield of cotton, supplying 70 PWR and mycorrhiza application for this plant are recommended for Birjand.

In order to investigate the effect of biofertilizers on growth indices of maize (Zea mays L. ) in lead-contaminated soils, a factorial experiment with three iterations was conducted, based on a completely randomized design in a greenhouse of the soil science department at Zanjan University in 2015. Factor I included soil contamination levels of lead (0, 50, 100, 200, and 400 mg / kg soil) with Factor Ι Ι being no inoculation (C), inoculation with soluble bacteria Phosphate (Pseudomonas putida) (P), inoculation with Funneliformis mosseae (M), inoculation with mycorrhizal fungus Funneliformis mosseae + phosphate solubilizing bacterium (M + P), inoculation with Rhizophagus intraradices mycorrhizal (I), and inoculation with mycorrhizal fungi Rhizophagus intraradices + phosphate-solubilizing bacterium (I + P). The measured parameters were leaf chlorophyll index, plant height, fresh and dry weight of root and shoot, phosphorus and potassium of root, and the lead content in the shoots and roots. It has been shown that inoculation of soil with mycorrhizal fungi and bacteria improve plant growth and yield indices in the absence of lead. Inoculation with mycorrhizal fungus Funneliformis mosseae + phosphate-solubilizing bacterium (I + P) increase leaf chlorophyll index (11. 65%), root phosphorus (161. 5%), shoot phosphorus (237%), root potassium (35. 6%), and shoot potassium (62. 01%), compared to the no-inoculation treatment (control). Also, biofertilizers are proven capable of increasing the amount of absorbed lead in the plant root, compared to the control treatment by 61. 9%. In other words, they have been able to retain the absorbed lead from the soil by the plant root. According to the obtained results, at a critical concentration of lead (400 mg/kg soil), biofertilizers could not have a beneficial and increasing effect on chlorophyll index, height, and fresh and dry weight of the roots and shoots. However, at lower concentrations of Pb, they are able to decrease the harmful and adverse effects of these heavy metals on the shoots and roots of the plant.

In order to study the effect of silicon on biochemical traits, leaf relative water content, and yield of two bread and durum wheat cultivars under late season water stress conditions, a split factorial experiment have been conducted in a randomized complete block design in three replicates at College of Agriculture and Natural resources of Darab, during 2017-2018 growing season. The treatments include water stress in two levels, i. e., normal irrigation and water stress at the end of flowering, silicon (Si) spraying at 0, 1, 2, and 3 mM, and two wheat cultivars: Chamran as bread wheat and Shabrang as durum wheat. Results show that the main effects of late seasonal water stress, cultivar and silicon on leaf relative water content (RWC), total chlorophyll, carotenoid content, and yield have been significant. Under water stress conditions, when the plants are exposed to 3 mM silicon, RWC rises by 50%, compared to no silicon application conditions. Grain protein under water stress conditions and 3 mM silicon was 59. 3% higher than no silicon condition. Also, total chlorophyll content and carotenoid content under water stress conditions and application of 3 mM silicon have increased by 42. 5% and 44. 9%, respectively. In Chamran cultivar, application of silicon at 3 mM has raised total chlorophyll content, carotenoid content, RWC, and grain protein by 40%, 43%, 42%, and 56. 4%, respectively, causing a 19. 7% increase in grain yield, compared to Shabrang cultivar under water stress conditions. Calculation of correlation coefficients between grain yield and other traits shows that under normal irrigation conditions, the highest correlation could be observed between grain yield with total chlorophyll (r =0. 815 **) and number of spike per square meter (r =0. 814**) and under stress conditions between grain yield with number of spike per square meter (r =0. 937**) and total chlorophyll (r = 0. 840**). In general, by improving total chlorophyll content, carotenoid content, and RWC, foliar application of 3 mM silicon can play an important role in increasing grain yield, especially under water stress conditions.

Farmers have been traditionally using fire and smoke in various parts of agriculture. Several studies have reported that smoke bioactive components act as a new family of plant growth regulators. In order to evaluate and explore the potential of smoke-water as a phytohormone on growth characteristics and biological yield of medicinal plants of basil and lemon balm, an experiment has been conducted as a split plot based on complete randomized block design with three replications. Conducted at research greenhouse of Razi University in 2017, the study has eight factors, including four concentrations smoke-water (i. e., 1: 5000, 1: 1000, 1: 500, and 1: 100 (v/v)) accompanied with cytokinin, auxin, and gibberellic acid (each with a concentration of 50 μ M), as well as the control, assigned to the main plots, and two harvest stages, assigned to the sub plots. Results indicate that the gibberellic acid significantly increases basil canopy height in comparison to others treatments, while the maximum canopy height in lemon balm has been obtained from smoke-water at concentrations of 1: 500 (v/v). Foliarapplication with cytokinin result in the highest leaf area index in both plants, compared to the control. Eventually, the highest biomass yield in basil and lemon balm belongs to smoke-water at concentrations of 1: 100 (v/v) that has increased by 52% and 39%, respectively, compared with the control. In the current study, applying high level of smoke-water foliar (1: 100 and 1: 500 (v/v)) induces growth characteristics and biological yield, similar to phytohormone treatments, especially cytokinin.

Peppermint is an important medicinal and aromatic plant, whose content varies from one region to another, not to mention as a function of fertilization, shadow, irrigation, and photoperiod. In order to study the effect of different levels of shadow and nitrogen on growth and oil performance of this plant, a factorial experiment has been conducted using a completely randomized design with three replications in the Faculty of Agriculture, University of Zanjan during the 2014-2015 cropping season. The experimental factors are shadow factor in four levels (S0: without shadow, S25: 25%, S50: 50%, and S75: 75% shadow) and nitrogen factor as Urea in four levels (N1: without nitrogen, N2: 60, N3: 120, and N4: 180 mg N/kg). Results show that the highest number of leaves per plant (936), leaf surface area (1688mm2), chlorophyll index (51. 32), essential oil content (2. 455%), and essential oil yield (0. 37 g/box) have been obtained from the S25N3 treatment. The highest shoot dry weight belongs to S50N4 and S25N3 treatment with an 8. 36% gap to the second place. The highest leaf dry weight has been observed in S25N3 (11. 55 g/box). Treatments applied to plant height and the numbers of branches have not been significantly affected; therefore, to obtain the highest concentration and performance of essential oil in peppermint, as well as to increase the number of leaves per plant and leaf surface area for marketable and edible consumption, the use of 25% shadow and the application of 120 mg/kg nitrogen are recommended.

In order to investigate the effect of glycine betaine (GB) on some growth and yield traits of Damask Rose, an experiment has been conducted as factorial based on a completely randomized design with 3 replications at Research Greenhouse of National Salinity Research Center during 2018-19 growing season. The treatments include four levels of salinity: 2 (control), 5, 8, and 11 dS/m, and three levels of GB: without application (control), spraying with 50 mM, and 100 mM concentrations. Results show that the main effect of salinity stress has been significant on all studied characteristics, with the exception of branch number per plant and petal number. Moreover, the main effect of GB has been significant on all measured traits, except for branch number per plant, petal number, height, and petal weight/flower weight ratio. The highest flower number per plant, flower yield, and essential oil yield belongs to stressed plants at 2, 5, and 8 dS/m salinity, which have had about 7. 5 flowers, 29. 5 g flower weight per plant, and 6 mg essential oil per plant than 11 dS/m treatment, respectively. The interaction results between salinity stress and foliar application of glycine betaine show that the treated plants with 2 dS/m and 100mM GB have had the highest height (71 cm) and the treated plants with 10 dS/m and without application of GB have had the lowest height (40 cm). In general, the use of 50 mM GB and without salinity stress causes the highest Damask Rose weight.

In order to determine the rosemary (Rosmarinus officinalis L. ) dry matter and weeds under different fertilizer sources, an experiment was conducted as a split plot in a randomized complete block design with three replications at Sari Agricultural Sciences and Natural Resources University in 2016. In this experiment, the treatments include competition between plants and weeds (weedy check and weed free) as the main factor, with the sub factor being fertilizer sources, namely sheep manure, vermicompost, sheep manure + vermicompost, NPK chemical fertilizer (N 46%, P2O5 46%, and K2O 50%), NPK Nano-fertilizer, and the control (no fertilizer). Results show that competition with weeds cause rosemary shift the maximum dry matter to the upper layers of canopy (20-40 cm), while in weed free treatment, rosemary has had higher ability and uniformity in dry matter distribution in the two primary canopy layers, compared to competition with weeds. In this regard, vermicompost treatment has been successful with a mean of 49. 51 g plant-1. Studies on density and weed biomass show that the use of vermicompost (treatment 2) reduce density and biomass of weeds, while the chemical fertilizer causes the highest weed density and biomass. According to the results, the use of organic fertilizers such as vermicompost, not only reduce the use of chemical fertilizers and do not have environmental consequences, but have also the high ability to suppress weeds growth and decrease weed density and biomass.

In order to study the role of fruit tree rootstocks on nutrient content in the leaves of two Iranian red flesh apple genotypes and to determine the correlation of nutrients with different secondary metabolites, the present study has been conducted in Research Garden of Horticultural Sciences of Ferdowsi University of Mashhad during 2016-2019. The used rootstocks are two dwarfing rootstocks, M9 and B9, along with one red flesh apple colony rootstock of Bekran; all, tested in a factorial randomized complete block design. Results from this study show that the rootstock has had a significant impact on nitrogen and phosphorus content in leaf samples of two red flesh apple genotypes and red delicious cultivar. Moreover, rootstock, scion, and their interaction have had a significant effect on potassium, iron, calcium, and zinc content of leaf samples. The effect of B9 on the amount of all elements of scion leaves has been negative and the effect of M9, positive in all cases. Results also show that PAL enzyme activity has been positively correlated with nitrogen, potassium, calcium, iron, and zinc. Similarly, anthocyanin synthesis has been positively correlated with nitrogen content (0. 47). The experience further demonstrates that the amount of potassium, calcium, and iron are highly correlated with UFGT activity, and that the total flavonoid content is also significantly correlated with calcium and zinc (0. 64 and-0. 45, respectively). It also shows that these effects could be due to the participation of some of these nutrients as cofactors in enzyme activity and/or precursors of phenolic compounds and secondary metabolites.

In soilless culture, lack of correct management in fertigation causes stress in plants due to restricted root volume and low water holding capacity of the substrate. The present study tries to assess management of fertigation practice and foliar application of potassium sulfate in a soilless culture of strawberry cv. paros. For this purpose, a factorial experiment has been conducted with two factors, namely fertigation frequency at three levels (1, 4, and 10 times per day) and foliar application with potassium sulfate at three levels of concentration (0 as control, 1, and 2 g/L). The experiment has been carried out based on a complete randomized design with three replications in Vali-e-Asr University of Rafsanjan. Results show that increasing the fertigation frequency up to four times a day leads to a significant increase in dry weight of shoot and root, number of fruits, concentration of chlorophyll a and b, leaf relative water content, and leaf Ca and Mg content. The highest values of leaf area, fruit weight, number of inflorescences, as well as potassium and iron content of leaf and root have been obtained by 10 times of fertigation per day. Application of potassium sulfate foliar with a concentration of 1 g/L has had the greatest impact on leaf area as well as shoot, root, and fruit dry weight. Vegetation index has increased in plants, treated with 2 g/L potassium sulfate, compared with those without any foliar application treatment. The highest content of leaf soluble carbohydrates belongs to the plants, treated with once-a-day fertigation and foliar application of 2 g/L potassium sulfate.