جستجوی مقالات مرتبط با کلیدواژه "شاخص گلوتن" در نشریات گروه "زراعت"

Scarce water resources and raising salinity are limiting factors affecting wheat production in arid and semi-arid regions. Many studies have been conducted to release appropriate wheat cultivars for saline and non-saline conditions. But due to the co-existence of drought and salinity stress in arid and semi-arid regions, it is necessary to introduce cultivars that could tolerate salt under water shortage conditions. Results of the studies conducted at the Iranian Dryland Agricultural Research Institute have led to introduction of wheat cultivars with low water requirements due to early maturity. So, if the yield of these cultivars be optimum in saline media, they could be a suitable option for planting in these conditions. The objective of the study was to evaluate the salinity response of three dryland wheat cultivars in water limitation conditions compared to the local check.

To investigate the response to salinity of three early ripening dryland wheat cultivars along with a commercial irrigated wheat variety cultivated in the region, a field experiment was carried out as split plot during the 2020-2021 cropping season in Yazd province, central Iran. Treatments were irrigation water salinity with two levels of 2.5 and 10 dS m-1 as main plots, and three dryland cultivars of Asman, Aftab, and Kohdasht along with the irrigated cultivar of Barzegar as sub plots. All examined cultivars were planted on November 15. Row spacing was 20 cm with a planting density of 500 kernels/m2. The plots were subjected to saline irrigation water for 7 times from seeding to physiological maturity, and the irrigation was cut-off when physiological maturity occurred in dryland cultivars. Total water consumed throughout the growing period was 7794.8 m3 ha-1. Leaf area index was measured by sampling at plant establishment, tillering, mid-stem elongation, spike emergence, and kernel milky and dough stages. At harvesting, total above-ground dry mass and grain yield, harvest index, plant height and thousand kernel weight were measured. The grain quality attributes including hectoliter weight, protein content, zeleny sedimentation volume, bread volume, hardness index, flour water absorption, wet gluten percent, gluten index and sedimentation height were also measured. Data were analyzed using SAS 9.4 software, and the means were compared using the LSD test at the 5% probability level.

Results showed that the effect of salinity on grain yield and gluten index was significant. Grain protein content was not affected by salinity. The grain yields of Aftab, Aseman, Barzegar and Kohdasht cultivars in saline conditions were 527, 363, 447, and 207 g m-2, respectively; indicating 25, 33, 12 and 55% decreases compared to non-saline conditions. Literature generally confirms 15-30% decreases in wheat grain yield under irrigation with saline water of 8-10 dS m-1. Aftab as a dryland variety produced the highest grain yield, i.e. 617 g m-2. The grain yields of Barzegar, Aseman and Kohdasht were 23, 27 and 46% lower compared to Aftab, respectively. Due to irrigation cut-off and failure to complete the growth period, Barzegar had the lowest thousand kernel weight under both saline and non-saline conditions. The highest hectoliter weight and gluten index were observed in Aftab under both conditions. Grain protein was not affected by the irrigation water salinities. The value for grain protein content of the cultivars was around 11.45% without significant difference in both non-saline and saline conditions. The amount of leaf area index for all cultivars was lower in saline conditions than the non-saline conditions. Irrigation with saline water decreased the leaf area index of Aftab, Aseman, and Kohdasht cultivars by 41, 30, and 52% compared to non-saline condition, respectively. As the leaf area index has a major role in current photosynthesis for assimilate partitioning, its decrease leads to a decrease in plant above-ground dry mass, harvest index, and finally grain yield.

Based on the results, Barzegar as local check suffered more damage from drought stress in both saline and non-saline conditions due to its late maturity. Therefore, under similar situation, Aftab cultivar could be a suitable candidate for areas where water resources are both scarce and saline. In addition, early wheat varieties may be considered as an effective factor in selecting suitable cultivars for arid and semi-arid regions, regardless of salinity.

To study the effect of different levels of nitrogen and potassium fertilizers on grain yield and quality properties of durum wheat cultivars, a field experiment was carried out in the research filed of the Seed and Plant Improvement Institute in Karaj, Iran, in 2019-20 and 2020-21 cropping seasons. Split plot arrangements in randomized complete block design with three replications was employed to assess the effect of nitrogen and potassium fertilizers levels on grain yield and quality properties of two durum wheat cultivars. Two durum wheat cultivars (Hana and Sana) were assigned to main plots, and different levels of urea and potassium sulfate fertilizers (control, 200, 300, 400 kg ha-1 urea (N) and each level of nitrogen fertilizer with 100 and 200 kg.ha-1 potassium sulfate (K)) were randomized in sub-plots. The results showed that the effect of year and different fertilizer levels on grain yield was significant (P ≤ 0.01). The grain yield increased by increasing nitrogen and potassium fertilizer levels. It was notable that the simultaneous application of these two fertilizers showed greater effect on grain yield. Therefore, grain yield at 300 kg ha-1 of urea fertilizer plus 200 kg ha-1 of potassium sulfate fertilizer was higher than sole 400 kg ha-1 urea fertilizer. Quality properties included; hectoliter weight, grain protein content, zeleny sedimentation volume, grain hardness index, grain wet gluten content, gluten index, SDS sedimentation height, semolina extraction rate and grain yellow berry percentage. The combined analysis of variance showed that there was significant differences among different fertilizer levels for all grain quality properties, and between years for wet gluten content, grain hardness, semolina extraction rate and grain yellow berry percentage. Wet gluten content, grain hardness and semolina extraction rate in 2019-20 were higher than in 2020-21 cropping season. Whereas, grain yellow berry percentage was higher in 2020-21 cropping season. In General, increasing the rate of fertilizers application increased all quality properties except grain yellow berry percentage that decreased by 76% at 400 kg ha-1 urea plus 200 kg ha-1 potassium sulfate as compared with control. It is concluded that application of 400 kg ha-1 urea plus 200 kg ha-1 potassium sulfate could be sufficient for optimizing grain yield and quality properties of durum wheat in Karaj region.

Drought stress is the most prevalent and limiting factor in the growth and productivity of crop plants. According to the challenge of deficiency in precipitation or consecutive droughts in recent years in Iran and as a result of a shortage of irrigation water in wheat production, knowledge of the relationship between grain quality and grain yield under drought stress can be particularly important to identify lines with drought tolerance. The present study, hence, evaluated the effects of drought stress on the grain quality of 104 F5 lines derived from a cross between Barat × Nogal in wheat.

The effects of drought stress on grain-quality-related traits of wheat were investigated using 104 F5 lines under normal and drought conditions. A randomized complete block design with three replications was used in each environment in the 2020-2021 cropping season. Grain yield, protein yield, grain hardness, Zeleny sedimentation volume, protein content, bread volume, gluten content, and gluten index were evaluated.

Analysis of variance showed that there was significant genetic variation in the lines for all traits in both environmental conditions. Stress and stress × line interactions were also significant for all of the studied traits. Mean comparison of lines showed that the quality in bread wheat was improved under drought stress conditions due to increment in protein content and grain hardness. The highest grain protein content was found in lines 10, 52, 54, 68, and 71 with 12.96% under normal conditions, while it was found in lines 10, 28, 32, 61, and 93 with 13.94% under drought-stress conditions. Although the growth and consequently grain yield were limited under drought stress conditions, increased concentrations of grain‐derived ingredients including protein content, gluten content, gluten index, and Zeleny volume were noted. On the other hand, grain protein showed a significant and positive correlation with the Zeleny volume and water absorption in both environmental conditions.

From the work carried out it can be concluded that firstly, selection of wheat lines in respect to grain quality must be undertaken separately for each of the normal and stressed environments, and secondly that the grain quality of wheat lines under drought stress conditions was significantly better than that of normal field conditions.

Nitrogen is a determining element in nutrition, plant growth, and its quantitative and qualitative performance. Considering the high cultivated area of dryland wheat in the country and the economical importance of this crop in dryland conditions, it is necessary to consider any solution to optimize the quantity and quality of this product.

a strip split plot design based on RCBD with three replicates was conducted under rainfed and supplemental irrigation conditions during two cropping seasons (2016-17 and 2017-18) to evaluate the effect of Nitrogen (urea) applied by different foliar application treatments and top dressing fertilizer on grain yield, grain protein content, Zeleny number, and gluten index of wheat, Experimental treatments were: A: control (without application of N), foliar application of urea during booting, booting + grain filling and grain filling stages as the main plot, B: wheat cultivars as sub-plots, C: top dressing fertilizer including application and non-application (control) in strip factor were considered.

The results of a combined analysis of variance and mean comparison showed that foliar spraying of urea fertilizer in all three growth stages significantly increased grain yield, nitrogen content, the percentage of grain protein and grain hardness, Zeleny number and grain gluten index. The application of top dressing fertilizer in both rainfed and supplementary irrigation conditions on grain yield, grain protein and gluten index was also significant. The highest gluten index in rainfed conditions (24.08%) and supplementary irrigation (16.19%) was related to foliar application of urea during the grain filling stage. The highest index of gluten, grain hardness and Zeleny number in both rainfed and supplementary irrigation conditions belonged to Rijaw variety. Rijaw variety had the highest value with 27.3 and Azar-2 variety had the lowest gluten index value with 18.6. Foliar application of urea during the grain filling stage had the most contribution to the increase of grain protein and the control treatment had the least contribution. The highest amount of grain yield in rainfed conditions was 2907 and in supplementary irrigation conditions were 3957 kg, which compared to the control treatment (no application of vinegar fertilizer), increased the grain yield by 19 and 16% in both rainfed and supplementary irrigation conditions, respectively.

The results of this research showed that foliar application treatments and top dressing fertilizer in both rainfed conditions and supplementary irrigation were effective in improving quality traits. In this study, supplementary irrigation led to a significant increase in grain yield compared to rainfed conditions.

To determine the effect of macro- and micro- nutrients applicaton on quantity and quality related traits of two wheat cultivars (Parsi and Marvdasht)، a split plot arragement experiment in randomaized complete block design with three replications was carried out at Karaj SPII، experimental field during two cropping seasons 2010-2012. The main plots were nutrition management including no application of fertilizer (control)، macro-nutrient and macro + micro-nutrient. Two bread wheat cultivars were randomized in sub-plots. Grain yield، 1000 grain weight، protein content، wet gluten (%)، gluten index، Zeleny sedimentation volume، SDS- sedimentation height، falling number and bread volume were measured. Combined analysis of variance showed that nutrition management effect on the grain yield، grain protein contant (%)، SDS، Zeleny، wet gluten (%)، gluten index، hardness index and bread volume was significant. Results showed that cultivar effect on 1000 grain weight، wet gluten (%)، gluten index، bread volume and falling number was significant. Parsi had the highest grain yield and grain quality related traits (except gluten index).

To study the genetic variation in baking quality related characteristics bread wheat commercial cultivars and advanced breeding lines, an experiment was conducted with 85 cultivars/lines- using an α-lattice design with three replications. Thirteen characteristics including; 1000 grain weight, hectoliter weight, grain protein content, Zeleny sedimentation volume, bread volume, grain moisture (%), grain hardness, falling number, wet gluten (%), dry gluten (%), gluten index, SDS-sedimentation volume, as well as four farinograph components: dough development time, dough stability, degree of softening (after 10 and 12 minutes), were measured. Analysis of variance showed significant differences among genotypes for all traits. This shows high genetic variation among the cultivars and advance lines. Multivariate factor analysis performed for 12 traits, and found that three common factors defined 97% of observed variation. The first factor defined 78.55% of variation including farinogram triats. The second factor explained 16.78% of variation included; protein content, bread volume and Zeleny sedimentation volume, and the third factor explained only 1.75% of variation included; gluten index and SDS-sedimentation volume. Cluster analysis based on variances of inta-groups recognized four different clusters. The cluster with high bread making quality consisted of 23 cultivars and advanced lines. This findings would be employed in bread wheat breeding program to improve the baking quality characteristics in breeding materials.

To study the response of 180 genotypes of hexaploid wheat to terminal drought stress for grain yield and baking quality properties, a field experiment was conducted at reasearch field station of Seed and Plant Improvement Institute (SPII), Karaj, Iran in 2005-2006 cropping season. Genotypes were planted in two separated experiments simulating non-stress and stress (applied from anthesis to physiologic maturity) conditions using an unreplicated systematic experimental design. Following identification and classification of genotypes in three groups: tolerant genotypes with reasonable yield potential (group A of Fernandez), genotypes with reasonable yield potential and susceptible to drought stress (group B of Fernandez) and moderately tolerant genotypes, genotypes of these three groups were evaluated for baking quality properties. Results of this experiments showed the theory of ''improving bread quality properties of bread wheat under stress conditions'' is only applicable to susceptible genotypes and to some extents to moderately tolerant genotypes, due mainly to increased grain protein content followed by reduction of 1000 grain weight in stress conditions. This theory is not relevant to drought tolerant genotypes, because in these genotypes no considerable change in proportion of protein content to carbohydrates was observed, under stress conditions. The results of this study suggested that identification and selection of genotypess with high grain yield and desirable baking quality properties under non-stress and stress conditions practicable. In this study 7 drought tolerant genotypes with good baking quality were identified in both non-stress and stress conditions. Although susceptible genotypes may gain better baking quality properties under stress conditions, but this is usually compensated by yield penalty.