s .sanjani

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.

The quality of bread wheat grain not only affects the efficiency and production of flour, but it also contributes to the production of a product with more favorable technological and sensory characteristics and longer shelf life which by reducing waste and increasing productivity ensures the improvement of production chain efficiency from farm to table. Therefore, the current research was carried out to evaluate grain quality of irrigated bread wheat produced by farmers in the southern warm and dry agro-climatic zone provinces in 2018-2021. For this purpose, 642 irrigated bread wheat grain samples were collected from 10 provinces in the southern warm and dry agro-climatic zone of Iran, and the physical properties of the grain and the physico-chemical characteristics of flour for each cultivar in each province were evaluated. The results showed that Fars province with 43.1±2.4 g and Kohgiluyeh & Boyer-Ahmad province with 36.1±3.5 g had the highest and lowest 1000 grain weight, respectively. Cv. Chamran 2 had the highest (45.5±2.1 g) 1000 grain weight in Fars and the lowest (35.5±3.8 g) in Kohgiluyeh & Boyer-Ahmad. Also, the wheat grain samples produced in this agro-climatic zone were identified as “very heavy grain” considering average hectoliter weight (80.2±0.8 kg/hL). On the other hand, the highest protein content was observed in Khuzestan (12.4%) and Bushehr (12.1±0.3%) provinces, respectively. Fars province had the highest (27.0±1.4%) wet gluten content. By evaluating the grain hardness, it was revealed that cv. Mehregan had the highest (52.8±4.4) grain hardness index in Bushehr province and the lowest (49.0±1.4) in Lorestan. The highest and lowest grain hardness index, gluten index, zeleny sedimentation volume and SDS sedimentation height were observed in grain samples from Khuzestan and Kohgiluyeh & Boyer-Ahmad provinces, respectively. Finally, considering the observed variation in quality properties of grain samples of irrigated bread wheat cultivars in Iran which is affected by the differences in agro-climatic and field management practices, it is suggested that wheat grains produced, with high quality, in the southern warm and dry agro-climatic zone be used to improve the quality of end-use products of grains with lower quality produced in some other provinces in Iran.

Wheat (Triticum aestivum L.) is one of the most important crops in the world as well as in Iran. It has experienced many improvements in terms of yield and quality traits during recent decades. Wheat, like energy, is known as a strategic commodity and is one of the important indicators of agriculture. This plant has the highest area under cultivation and production among other cereals in the world. Planting date is an important factor in crop production because meteorological parameters vary with changes in planting date. Delay in planting is one of the problems that is common in almost all wheat growing areas of Iran and is one of the main causes of reduced yields of wheat cultivars. Yield reduction rate varies depending on the delay in planting and cultivars, and the results of some experiments indicate that this amount sometimes reaches more than 35% of potential grain yield. Phenology and growth rate due to their effect on duration and the occurrence of different stages of development and the environmental conditions prevailing in each of these stages, are the key point of adaptation to various environmental conditions such as delayed planting date. This experiment was designed to identify the changes in yield and yield components and phenological stages of new bread wheat cultivars with different growth habits and to investigate the possibility of introducing cultivars compatible with delayed planting date in the region.

This research was conducted in two separate experiments based on a complete randomized block design with optimum planting date (6th November) and delayed planting date (6th December) on 10 new bread wheat cultivars with three replications on the research farm of the Seed and Plant Improvement Research Institute in Karaj in two years (2016-2018). The bread wheat cultivars include Pishgam, Heidari, Rakhshan, Sivand, Baharan, Sirvan, Parsi, Mehregan, Chamran 2 and Chamran. Yield and yield components such as number spike per m2, number of grain per spike, 1000-grain weight were measured at the end of the growing season to evaluate responses of the cultivars to the various planting dates. In addition, the phenological stage was recorded during the growing season.

Results indicated that delayed planting date from 15th Nov. to 15th Dec. caused a significant reduction on grain yield (from 7485 to 6066 kg.ha-1), number of spikes per m2 (from 698 to 605), number of grain per spike (from 28.5 to 25.8 seed), and 1000 grain weight (from 41.1 to 38.4 g). The interaction effects of planting date and cultivars were significant on grain yield and yield components. The highest and lowest grain yield belonged to Pishgam (7436 kg. ha-1) on optimum planting date and Chamran (5842 kg.ha-1) on delayed planting date, respectively. Delayed planting date reduced duration of planting to double ridge (from 736 to 641 GDD), planting to terminal spikelet (from 982 to 886 GDD), planting to anthesis (from 1608 to 1457 GDD) and planting to maturity (from 2456 to 2265 GDD).

Duration of different developmental stage is very important for the formation of yield components that determine the final grain yield. Although these stages are a genetic trait, but they are affected by plant growth conditions and environmental stresses, climatic factors, especially temperature and day length. Our research showed that delay in planting reduced grain yield by 18% compared to the optimum planting date because of the reduced number of spikes per m2 and vegetative and grain-filling periods.Based on the results, in cases of delayed planting date (unfavorable weather conditions, insufficient planting equipment, etc.) in Karaj region or similar climatic regions, early maturity cultivars such as Mehregan and Chamran 2 and moderate maturity cultivar like Sivand are recommended in order to minimize yield loss.

In order to evaluate the effect of intercropping with replacement and additive series for hemp (Cannabis sativa L.) and sesame (Sesamum indicum L.), a field experiment was conducted during growing season 2006-07 at the Agricultural Research Station of Ferdowsi University of Mashhad, Iran. A randomized complete block design with three replications was used. Treatments included different combinations of intercropping with replacement (75%sesame+ 25% hemp, 25%sesame+ 75% hemp, 50%sesame+ 50% hemp) and additive (50%sesame+ 100% hemp and 100%sesame+ 50% hemp) series and their monoculture. Results indicated that the highest and the lowest leaf area index (LAI) and dry matter (DM) accumulation of hemp were observed in 50% sesame+ 50% hemp (2.99 and 1921.7 g.m-2) and 50% sesame +100% hemp (1.06 and 929 g.m-2), respectively. The highest and the lowest LAI and DM accumulation of sesame were observed in monoculture (1.34 and 551.27 g.m-2) and 50%sesame+ 100% hemp (0.23 and 51.73 g.m-2), respectively. The maximum crop growth rate (CGR) of hemp and sesame were observed in 50% sesame+ 50% hemp (76.58 gm-2day-1) and monoculture (22.78 gm-2day-1), respectively. It seems that the intercropped sesame with hemp reduced the growth indices of sesame due to increasing shading on it and decreasing the absorption of radiation.