جستجوی مقالات مرتبط با کلیدواژه "head diameter" در نشریات گروه "زراعت"

To evaluate the effect of autumn sowing date on seed yield of sunflower cultivars, a field experiment was carried out as strip plot arrangement in randomized complete block design with three replications in safiabad agricultural and natural resources research and education center of Dezful, Iran during two growing seasons (201718 and 2018-19). Seven sowing dates (6th Sep., 23rd Sep., 7th Oct., 22nd Oct., 6th Nov., 21st Nov. and 6th Dec.) were assigned to vertical strips and five sunflower cultivars (Azargol, Barzegar, Progress, Farokh and Lakomka) were randomized in horizontal strips. Mean comparison of sowing date and cultivar interaction showed that the highest growth duration (204 days) belonged to sowing date of 21st Nov. and cv. Progress. The lowest growth duration (118 days) was for cv. Farokh in sowing date of 6th Sep. Delay in sowing date led to decrease in head diameter and thousand seed weight of all sunflower cultivars. Delaying in the sowing date also led to shorter plant height. The highest (42.8%) and the lowest (37.7%) seed oil content was observed in the first (6th Sep.) and the last (6th Dec.) sowing dates, respectively. Cv. Azargol (41.9%) and cv. Farokh (38%) had the highest and the lowest seed oil content. Mean comparisons of sowing date and cultivar showed that the highest seed yield (2985 kg.ha-1) belonged to the first sowing date (6th Sep.) and cv. Progress. The lowest seed yield
(232 kg.ha-1) obtained from cv. Lakomka in 6th Dec. sowing date. The results of this experiment showed that the period of 6th until 23rd Sep. is suitable sowing date window for autuom sowing sunflower in the north of Khuzestan province.

The high cost of chemical fertilizers used in agriculture and the environmental problems due to their use reveal the need to reappraise conventional plant nutrition practices. Integrated use of biofertilizers combined with synthetic fertilizers is one of the essential sustainable agricultural strategies. To this end, this study was carried out by using a factorial experiment based on randomized complete block design with three replications at the experimental field of Islamic Azad University, Ahvaz Branch during 2018 cropping season. The first factor was different amounts of triple superphosphate fertilizer with three levels (0, 50 and 100 kg.ha-1) and the second factor was phosphorus biofertilizer also with three levels (0, 100 and 200 g.ha-1). Result of analysis of variance revealed that the effect of different levels of biophosphorus fertilizer and triple superphosphate on all measured characteristics were significant but the interaction effect of treatments was not significant. Based on the results of this study, the highest seed yield, 1000 seed weight, seed oil percentage, head diameter and number of seed per head and lowest empty seed belonged to the use of 100 kg.ha-1 triple superphosphate with 200 g.ha-1 biophosphorus fertilizer. It seems triple superphosphate fertilizer to increase the concentration of soil cadmium by 54%, due to its impurities, including heavy elements, but increasing the levels of phosphorus fertilizer in the soil reduces the concentration of cadmium by 45%. According to these results, the application of 100 kg.ha-1 of triple superphosphate and 200 g.ha-1 of phosphorus fertilizer per hectare, compared to other treatments, may increase seed yield and absorption of elements of sunflower in this region.

This experiment was conducted to evaluate the effect of deficit irrigation on seed yield and its components of sunflower hybrids, and also identify tolerant hybrids. Twelve sunflower hybrids; Farrokh, Shams, Ghasem, Barzegar, G5 ×43, G6×43, Hysun25, Hysun36, Azargol, Sumbro, Euroflor and Sirena were evaluated under three irrigation treatments; normal irrigation (60 mm), mild drought stress (120 mm) and severe drought stress (180 mm) evaportation from Class A Pan, using split plot arrangements in randomized complete block design with three replications in Islamabad Gharb research station, Iran in 2012 and 2013 cropping seasons. Irrigation treatments were assigned to main plots, and sunflower hybrids were randomized in sub plots. Results of combined analysis of variance showed that irrigation treatments had significant effect on growth duration, stem diameter, head diameter, seed per head, 1000 seed weight and seed yield, but had no significanteffect on seed oil content. Sunflower hybrids were significantly difference for growth duration, 1000 seed weight and seed yield. Interaction effect sunflower hybrid×irrigation was not significant for any of measured traits. Mean comparison showed that seed yield of sunflower hybrids was more affected by irrigation treatments than other traits, as average seed yield in normal irrigation, mild drought stress and severe drought stress were 4470, 3637 and 2832 kg ha-1, respectively. Reduction in seed yield was due to cumulative reduction in yield components such as head diameter, seed per head and 1000 seed weight. Sunflower hybrids were also different for growth duration, plant height, non-filled seed, head diameter, seed per head and 1000 seed weight. Barzegar and Sumbro hybrids had the highest and lowest seed yield (4091 and 3362 kg.ha-1, respecrively) and the the highest seed oil content was obtaind in Hysun36 hybrid (45.6%). The results showed that Barzegar hybrid had the higher seed yield in both full irrigation and deficit irrigation conditions, therefore it can be recommended to be grown under these conditions.

Oil seeds are important sources of vegetable oils. Safflower seed with 25-45% oil is one of the valuable oil seeds. Nowadays, people are aware of chemical fertilizers harmful effects on the environment. So the application of organic amendments is known as a suitable strategy to increase soil organic matter. One of the methods for utilization of aquatic waste is using them as an organic fertilizer. It is full of nutrients especially nitrogen and phosphorous that can eliminate their deficit in farms and gardens. Chitin found in the exoskeleton of shrimp is the second most ubiquitous natural nitrogenous polysaccharide after cellulose on earth. Huge amounts of fish wastes and shrimp have been abandoned by worldwide seafood companies. So using these renewable waste materials as fertilizer is economically feasible. Since nitrogen and phosphorus are essential elements in safflower growth, applying fish wastes and shrimp which are rich in these elements can improve the quantitative and qualitative characteristics of safflower. In order to investigate the effect of shrimp and fish wastes on safflower, an experiment was conducted in completely randomized design with 13 treatments (3 gr shrimp at the soil surface, 3 gr shrimp mixed with soil, 1.5 gr shrimp at soil surface, 1.5 gr shrimp mixed with soil, 3 gr shrimp + 0.2 gr urea at soil surface, 3 gr shrimp + 0.2 gr urea mixed with soil, 1.5 gr shrimp + 0.2 gr urea at soil surface, 1.5 gr shrimp + 0.2 gr urea mixed with soil, 5 gr fish at soil surface, 5 gr fish mixed with soil, 10 gr fish at soil surface, 10 gr fish mixed with soil, and control) and 4 replications in the University of Nahavand. Number of seed, head diameter, number of flowers per plant, number of branches per plant, 1000- grain weight, oil percentage fatty acid content and type were measured. The results represent the positive effect of shrimp and fish wastes on the studied traits so that the most head diameter (2.1 cm) was observed in the 1.5 gr shrimp at the soil surface treatment, the most seed number by application of 1.5 gr shrimp mixed with the soil, and the highest amount of 1000-grain weight (39.1 gr) in the treatment of 5 gr fish mixed with the soil. The most oil percentage (25.31%) was produced in 3 gr shrimp + 0.2 gr urea mixed with the soil. The most linoleic acid (73.56%) was produced with using 3 gr shrimp + 0.2 gr urea at soil surface and the most oleic acid (33.22%) and linolenic acid (0.38%) belonged to 1.5 gr shrimp + 0.2 gr urea at soil surface treatment. The highest amount of palmitic acid (11.32%) was created in 3 gr shrimp mixed with the soil and the most content of stearic acid (1.97%) in 10 gr fish at the soil surface treatment. The results showed the positive effect of fish and shrimp wastes especially shrimp, on all of the studied traits. Also, with the simultaneous application of organic and chemical fertilizers, the highest percentage of oil was produced. Considering the results of this study and in order to reduce the use of chemical fertilizers and to achieve sustainable agriculture purposes, we can use abundant fish and shrimp wastes as either an alternative or a complement for chemical fertilizers. Due to abundant sources of fish and shrimp waste in the south of Iran and high resistance of safflower to drought and salinity stress, use of aquatic waste as a fertilizer in safflower cultivation can be the subject of future researches.

Water deficiency is one of the most limiting factors of crop production throughout the world. Moreover, addition of fertilizers to supplement farm fertility is essential for crop production. In particular, microelements have important roles in seed formation and seed yield. Foliar sprays with fertilizers including microelements such as Zn and Si have been shown to be convenient for field use, have a good effectiveness and very rapid plant response. Hence, studying the effects of irrigation and fertilizer on agriculture is important in arid regions like most parts of Iran. Sharing 2.8% of total world oilseeds (around 107 million ton), sunflower is the fifth most important edible oil producer, following soybean, rape, cotton and peanut.
In order to investigate the effect of ZnO and SiO2 nano and conventional fertilizers application on yield, yield components and water use efficiency of sunflower in water deficit stress conditions an experiment was conducted as a split-plot based on a Randomized Complete Block Design with three replications at experimental field of Islamic Azad University, Birjand Branch, Birjand, Iran in 2014. The main plot was devoted to irrigation at two levels (irrigated after 100 and 200 mm cumulative evaporation from evaporation pan) and the sub-plot was devoted to foliar spray of ZnO and SiO2 at seven levels (nano ZnO, nano SiO2, ZnO, SiO2, nano ZnO nano SiO2, ZnO SiO2 and control or wihtout foliar spray). Measuring traits included the head diameter, seed number per head, 1000-seed weight, seed yield, biological yield, oil yield and water use efficiency for seed, biomass and oil. MSTAT-C statistical software used for data analysis and means compared with Duncan multiple range test at 5% probability level.
Results showed that water deficit stress decreased head diameter, seed number per head, 1000-seed weight, seed yield, biological yield, oil yield and water use efficiency for seed, biomass and oil by 16.9, 39.5, 18.5, 50.3, 33.3, 51.5, 73.7, 62.9 and 75%, respectively as compared to no-stress conditions (irrigation after 100 and 200 mm cumulative evaporation from evaporation pan). It can be said probably the stomata closure and as a result, the decrease in CO2 inflow to the plant decreased leaf area and duration and photosynthesis rate under limited irrigation conditions. Therefore, seed yield decreased because of the decrease in plant growing period, seed filling, head diameter, seed number per head and 1000-seed weight and probably the increase in unfilled head percentage. Also foliar application of conventional ZnO fertilizer significantly increased head diameter, seed number per head, seed yield and oil yield by 10.2, 42.9, 59.7 and 70.3%, respectively as compared to no-foliar application treatment. Zinc fertilizer has positive effect on auxin biosynthesis that can stimulate cell division and better absorption of minerals and thus increase the plant growth (Marschner, 2012). It seems that ZnO fertilizer mainly by increasing the seed number in head significantly seed yield increased. Probably zinc element participates in protein synthesis of the pollen tube during pollination, which leads to increase the seed number in head. The highest water use efficiency for seed and oil with means of 0.125 and 0.056 kg. m-3 respectively, was observed in treatment of ZnO application that was 77.8 and 75% higher compared to the control treatment, respectively. This result can be related to higher seed and oil yield in this treatment compared to other treatments of fertilizer.
It seems the use of zinc oxide fertilizer due to its role in improving the functioning of physiological and biochemical in plant (Malakoti & Lotfolahi, 2004) has increased photosynthetic capacity and especially by increasing the fertilization of flowers and seed number per head caused a significant increase in seed yield. Moreover, water deficit stress by stomata closure and decreasing in the photosynthetic capacity of plant and source power was significantly reduced seed number per head and 1000-seed weight and finally seed yield and oil yield of sunflower. In total, it is recommended treatment of irrigation after 100 mm cumulative evaporation from evaporation pan and foliar application of conventional ZnO for the cultivation of sunflower under conditions of this research.

To investigate the effect of water stress on morphological and agronomical characteristics of sunflower (oilseed hybrid Allestar)، an experiment based on randomized complete block design was conducted with three replications at the Experimental Station of Islamic Azad University، Tabriz branch. Water stress was applied as irrigation after five evaporation levels (50، 100، 150، 200 and 250 mm) from evaporation pan class A. Results showed that، increasing water stress significantly decreased head diameter، number of seeds per head، 100- seed weight، oil percent، harvest index، leaf area index and seed yield. Mean seed yield decreased from 4460، kg ha-1 in control (50 mm) to 3460، 3200، 2210، and 1810 kg ha-1 for 100، 150، 200، 250 mm evaporation، respectively. It was also revealed that leaf area index was the most sensitive morphological trait to water deficit and was declined significantly by increased drought stresses. Any delayed irrigation resulted in reduced crop yields through shortened reproduction period، reduced number of seeds produced and inability of assimilate transportation for seed filling.