جستجوی مقالات مرتبط با کلیدواژه « Sunflower » در نشریات گروه « اکولوژی »

Downy mildew caused by the oomycete Plasmopara halstedii (Farl.) Berl. et de Toni is one of the most harmful sunflower diseases. Among the various measures to control it, the most economical is the development of resistant genotypes. At present, Pl6, Pl8, and Plarg loci are promising for use in breeding, providing resistance to all known P. halstedii races. Microsatellite markers (SSR) help to control the transfer of genes that control resistance in breeding material. However, validation of the marker is needed to prove its reliability in gene detection. There was studied the polymorphism of 9 microsatellite loci in 196 sunflower lines with different resistance to downy mildew. The ORS328 microsatellite locus was chosen as a marker of the Pl6 gene. Amplified fragment with 271 bp allows identifying genotypes resistant to the race 330. The lines that are the sources of the Pl8 gene did not differ from the others in the allelic composition of the ORS781 locus. Among the analyzed breeding samples, no polymorphism was revealed at this locus. To identify the Plarg gene, SSR markers ORS662 and ORS509 were selected. The analysis of 12 samples of the F2 generation from RHA-419 × I3BC2 (VK585 × VK195) crossing at these loci showed that both markers are inherited codominantly. The studied DNA markers can be used in marker-assisted selection (MAS) of sunflower for resistance to downy mildew pathogen.

In order to assess the environmental impact of agricultural activity, the long-term sustainability should be considered. In order to achieve solutions to reduce energy consumption and carbon emissions in the production of rainfed sunflower, this assessment was conducted in the North East of Iran. Four production methods, i.e. conventional tillage (CT), tow reduced tillages (RT1and RT2) and direct seeding (NT) were evaluated. The highest energy consumption (12.3 GJ.ha-1) and carbon emissions (248 kg C-eq ha-1 and 155 kg C-eq t-1) were related to the conventional method. The least energy input (9.12 GJ ha-1) and carbon emission (183.3 kg C-eq ha-1 and 118.6 kg C-eq t-1), were related to NT method. The greatest amount of sustainability index (Is) was related to NT method, followed by RT2 (1.96), RT1 (1.79) and CT (1.53). In farm operations, fuel and nitrogen fertilizer were the key factors relating to energy use and carbon emission. In comparison of production methods, the conservation tillage was significantly more efficient. In conservation tillage, input energy and fuel consumption per hectare were 30% and 90% lower than conventional method, respectively, but there was no reduction in yield and energy output. Based on the lower power consumption and greater energy efficiency, conservation tillage methods (in particular, reduced tillage and no-tillage) was recommended to  replace the conventional tillage.

Aluminum is one of the most important heavy metals which not only can be easily absorbed by roots, but it also damages its normal function and blocks absorption of water and nutrients. According to this fact that sunflower has been widely used in industry, this study investigates the effects of aluminum toxicity on biochemical factors in two sunflower varieties including Sirena (tolerant) and Sanbero (sensitive). The study was carried out in a completely randomized design with aluminum (0, 100, 200, 300, 400, 700 µM) treatments and four replications in hydroponic culture. Experiments are conducted in establishment stage of the plant in four iterations at concentrations of 0, 100, 200, 300, 400, and 700 µm of aluminum. Results of biochemical tests show that aluminum, as a heavy metal, reduces the content of photosynthetic pigments and soluble sugars. In addition, it causes toxicity in sunflower plant. Increase in the proline content of two sunflower varieties show that varieties (Sirena and Sanbero) are more vigorous against oxidative stress with low concentrations of aluminum.

The sunflower oilseed and confectionaries types (Helianthus annuus L.) are definitely different in nutritional responses. This study attempted to evaluate differences in the expression levels of phosphorus and zinc arising from different fertilization treatments. The field experiment was conducted out at Agricultural Research Centre, in Islamic Azad University Arak, Iran, during 2011. Experiment was laid in split plot in randomized complete block design with 3 replications. Phosphorus treatments were in main plots and zinc in sub plots. Phosphorus levels were including 350, 175, 175 kg/ha triple super phosphate plus 100 g/ha phosphorus solublizing bacteria (PSB) and PSB alone and zinc levels were 0, 25 kg/ha soil application zinc sulphate, 25 kg/ha soil application of zinc sulphate plus 10% soluble zinc foliar application and soluble zinc foliar application alone. The results of roots quality in two sunflowers types showed P concentration in confectionary sunflower roots in all zinc levels was significantly higher. Use of 175 kg/ha triple super phosphate plus phosphorus solubilising bacteria (P < /font>3( or utilization of pure PSB (P < /font>4) in test plots was one of the main cause to increase phosphorus concentration in sunflower roots in check plots for zinc (Z1). Leaf phosphorus content was sharply higher in confectionary sunflower when fertilized with phosphorus and zinc mixture. High P application (P < sub>1) was the main cause for slow reduction in leaf zinc concentration for oilseed from 40 to 20 mg/kg. However, PSB and chemical phosphate use (P < sub>3) and PSB alone (P < sub>4) caused the leaf zinc content to increase significantly by foliar zinc application (Z4). Furthermore, the most zinc accumulation was detected in confectionary sunflower seeds by 55 mg/kg in PSB and chemical phosphate use treatment plus foliar soluble zinc application (P < sub>3Z4).