Due to having spring and autumn genotypes and adaptation to weather conditions, rapeseed is considered as a point hope to provide edible oil of country. Two separate experiments were set up as split-plot in a RCBD design with three replications in two fall and winter seasons during two years (2014-2015 and 2015-2016) at the research field of Seed and Plant Improvement Institute to investigate the effect of sowing season and date on the quantitative and qualitative yields of rapeseed genotypes in Karaj, Iran. In this study, the main plots were sowing dates (7, 17, and 27 October in fall sowing and 9 and 19 February, and 1 March in winter sowings) and sub-plots consisted of genotypes (RGS003, Dalgan, Zabol10, Hyola401, and Hyola4815). rapeseed genotypes grain and oil yields were 4330 and 1840 kg ha-1 in fall sowing, respectively, while these traits were decreased 43.3 and 46.6% respectively, when rapeseed genotypes were planted in winter season. The highest grain and oil yields (5033 and 2202 kg ha-1) belonged to 7 October sowing date in fall sowing, while 9 February had the highest grain and oil yields (2996 and 1248 kg ha-1) in winter sowing. In general, the Dalgan genotype is recommended for cultivation due to suitable agronomic traits such as number of silique per plant, number of grain per silique, silique length, 1000-grain weight, as well as high grain and oil yields in cold temperate regions with arid and semi-arid climates such as Karaj, Iran.

It is a double zero Brassica napus variaty which was received by the name of Ceres from the university of G6ttingen in Germany in 1989 and was tested in yield trials at Karaj Experimental Station. The variety was further evaluated in regional advanced yield trial in Karaj, Hamedan, Uromieh, Mashhad and Kermanshah for five years. It is high yielding and stable in different environments. Mean grain yield of that in Karaj, Hamedan, Uromieh and Mashhad was 3044, 2263, 3865 and 2737 kgha-1, respectively (Table 1 in Farsi text). It is cold tolerant and in case of loosing leaves in cold winters, is able to regenerate itself and produce new leaves. It has optimum lodging resistance so combine harvesting of that is possible. It is densely sub-branched and podded. Thousand kernel weight of that is 49 (Table 1) and it categoriyed as a late maturing rapeseed. Its erucic acid and glucosinolate of its meal are less than 2% and 30 µ mol g-1 of dry matter, respectively. It is moderately tolerant to sclerotinia disease.

The main purpose of this study was to determine rapeseed oil heat treatment effects onPopulus deltoides wood dimensional stability. For this purpose, free defect specimens with the dimensions of 2×2×2 cm were cut from poplar sapwood.The heat treatments were carried out at the temperatures of 180, 200 and 220oC for 2 and 4 h. Changes in weight and volume of the treated samples were measured.All samples were soaked in water for 5 days. Then, the water absorption and dimensional changes were determined. By the heat treatment with rapeseed oil, the specimen weight increased and volume of the specimens decreased. Linear relationship was obtained between sample volume reduction due to heating treatment, and time and temperature. The heat treatment improved the dimensional stability of poplar wood. With increasing temperature and time of treatment, the anti-swelling efficiency (ASE) was increased. At the temperature of 220 oC and 4 h treatment, ASE was 69%. In addition, water absorption of the treated samples was reduced. For instance at condition of 220 oC and 4 h the ASE was 135.7% less than that for the control sample.

To evaluate the grain yield stability of rapeseed promising lines in different environmental conditions, thirteen spring oilseed rape genotypes were assessed in a randomized complete block design with three replications in four locations (Karaj, Sari, Gorgan and Zabol) during two years (2015-2017). Simple analysis of variance showed that there was a significant difference between rapeseed lines in terms of grain yield at a probability level of 1%, which indicates that there is enough genetic diversity between them. In combined analysis of variance, the effects of year, location, year × location and genotype × location were also significant at 1% probability level. The comparison of mean grain yield showed that the rapeseed lines Simba, L104 and RGS003 produced the highest grain yield of 3105, 3058, 3032 kg ha-1, respectively. For stability analysis, different methods of stability including one-variable and regression methods (12 methods in total) were performed. Based on the integration of the results of these methods, three rapeseed lines Simba, L104 and RGS003 were stable and high yielding. For complementary studies, it will be recommended that these stable and high-yielding rapeseed lines be used in farm trials in target areas under farmer's conditions.

IntroductionAs suitable agricultural land for increasing crop production is decreasing, while the expansion of agricultural land is associated with irreparable damage to the environmen, intensifying sustainability in existing agricultural land is the only way to increase production to meet the increasing demand for food resources. Therefore, investigating the biophysical limitations on yield and estimating yield gaps  in the cultivated lands, as well as reducing this gap, is one of the ways to increase the yield per unit area. After soybean, rapeseed is the world's second produced oilseed. Ilam province is one of the most important oilseeds producer regions of the country, including rapeseed, and about 80% of the rapeseed crop of this province is produced in the border city of Dehloran, and this city is one of the pioneer cities and the main pole of rapeseed production in the province. Therefore, according to the importance of rapeseed in Deholran city, this study was conducted with the aim of determining the limiting factors of rapeseed production in Dehloran. Materials and MethodsIn the present study, all the management operations were performed from seedbed preparation to harvesting in 51 farms were recorded through field studies during the years 2021 to 2022. In this study, the yield gap was estimated by the method of yield comparison analysis and borderline analysis, and to determine the yield model, the relationship between quantitative and qualitative variables was measured and yield was evaluated by step-by-step regression method. Results and DiscussionDetermining the limiting factors on rapeseed production in the studied area showed that there was a gap between the actual yield of farmers and the yield predicted by the model of about 833.54 kgha-1, which was the contribution of the variables of potash fertilizer consumption, sulfur consumption, and the number of irrigations. The consumption of micronutrients from this yield interval was equal to 102.99, 118.56, 442.20 and 169.79 kgha-1, which is equivalent to 12.36, 14.22, 53.05 and 37, respectively. 20% of the total yield gap was observed. Gap analysis of rapeseed yield showed that the number of irrigations alone accounts for 53% of yield reduction compared to attainable yields.ConclusionAs, there is a need to irrigate the field in the very early planting date in October, it seems that with better management of rapeseed for this planting date in the region, the occurrence of drought stress can be reduced to the plant and to some extent fill the gap in the existing yield. In addition, 57% of the yield gaps in the region were related to the use of potash, sulfur and micronutrient fertilizers, which can be easily removed this limitations in the fields.

This investigation was conducted to evaluate the effects of the osmopriming on seed germination of rapeseed, under water stress condition. The design of the experiment was a factorial completely randomized design (CRD) with three replications. The experimental factors were three rapeseeds cultivars, (Cobra, SImo46 and Okapi), three levels of Osmopriming (0, -3, -6, -9, -12 and -15 bar) and three levels of water stress (-5, -10 and -15 bar). At the first stage seeds were immersed in one level of Osmopriming treatment for up to 48 hours at room temperature. Then the seeds were distilled by water for 24 h at 30°C and subjected to water stress treatments for two week. The results showed that Osmopriming technique had a significant effect (p<% 1) on seedling parameters including: dry weight of seedlings, length of radicles and plumules, rate and period of germination. The upper levels of osmopotential had more inhibition effect on plumula growth than the lower levels of osmopotential. Means comparing showed that the most and least rate of germination was obtained by Okapi and Cobra hybrids, respectively. Under water stress conditions Okapi hybrid had longer radicle, more lateral roots and higher proportion of root to plumule then the other cultivars. Thus this cultivar was more resistance ant to water stress.

To study the effects of water deficit on physiological indices and indentification of drought resistant cultivars of rapeseed among common cultivars in Eastern-Azarbijan, an expriment was carried out at Research Station of Factually of Agriculture, University of Tabriz, Tabriz, Iran. Genetic material was constituted of Global, Puma, Regent, Eureka and PF 7045.91 from napus species, Sonja and Parkland from rapa species and two hybrids, Hyola308 and Hyola 401. The experiment was conducted using a splite-plot design arranged in RCBD with 8 replications. Irrigation treatments with two level control and water deficit, were considered as main factor and cultivars as sub factors. Water deficit treatment was created by with holding irrigation at 50% flowering. Four weeks after induction of stress, physiological characteristics, including leaf water potential, specific leaf weight, and relative water content along with plant height, shoot dry weight, number and length of silique were measured. Mean of all traits, studied except specific leaf weight, were decreased under water deficit condition. Among the cultivars, studied global, had potentially higher number of silique, leaf water potential and shoot dry weight under both normal and water deficit condition, Thus, not only this genotype can directly be grown under water deficit condition but also can be used as one of the parent in developing mapping populations for identification of quantitative trait loci (QTL) for traits contributing in drought resistance.

rapeseed is one of the most important oily seeds which is cultivated in different parts of country in the recent years. Climatic feasibility and extension of rapeseed cultivation are very useful in this region due to widely governmental supports for cultivating oily seeds, in particular, rapeseed in order to reduce dependency on imports of this product and proximity to Mahidasht industry and cultivation complex as a guaranteed purchase market for this product in this province. In this research, temperature and precipitation features were studied during rapeseed growth period and each stage of growth and passing time of limit temperatures -7, -15 and 40oC at the level of studied stations were studied during 19-years (1992-2010) statistical period and then, by using GIS completely appropriate, appropriate, weak and inappropriate zones of rapeseed cultivation were specified at provincial level. The results of this research show that completely appropriate and appropriate regions corresponded to central and plain regions on this province cover about 70 percent of the studied region. Inappropriate zone corresponded to mountainous and high regions cover the lowest area (2302 km2) of the studied region and zones with weak capabilities for rapeseed growth allocates 7801 km2 of this province to themselves.

An experiment was designed to investigate the possibility of using rapeseed meal as a source of protein in dietary Arian broiler chickens. Five diets were tested in a completely randomized design. rapeseed meal was tested to replace soybean meal with the levels of 0 (control), 25, 50, 75 and 100 percent during the starter and grower periods. Feed intake during the grower period was lower in the 100% replacement (P<0.05). Body weight gain was also lower in the 100% replacement during the starter, grower and total feeding periods and was statistically different (P<0.05) from other treatments, while there was no significant difference among control and 25% replacement. Different levels of rapeseed meal in the diets also affected the feed conversion ratio (FCR). The FCR in the 100% replacement for the starter, grower and total feeding periods were statistically different (P<0.05) from that of the control and 25% replacement but no difference was found between control and 25% replacement. Chemical analysis of the rapeseed meal showed that the amount of progoitrin, gluconapin, napoleiferin and glucobrassicanapin were 44.2, 16.8, 10.5 and 7.5 µmol/g DM, respectively. These findings indicated that the aliphatic glucosinolates content of the meal is rather high, as compared to the accepted limit of 30 µmol/g DM of aliphatic glucosinolates in the canola meal. It can be concluded that 25% of soybean meal in the diet of Arian broiler chickens can be replaced with rapeseed meal as a source of protein.