فصلنامه تحقیقات غلات
سال نهم شماره 2 (تابستان 1398)

Evaluating the nature of behavior of time series for agricultural product prices plays an important role in improving policy making processes for managing and regulating food markets. Rice is one of the basic and most important foods in the food basket of Iranian households. In this research, the behavioral nature of the monthly time series of wholesale prices of common and top-notch Sadri rice during 1997-2016 (216 observations) was analyzed. To evaluate the statistical characteristics, trend modeling, principal component analysis, patterning the nature of behavior and recognition of seasonal and non-seasonal unit roots of these two time series were investigated. The results showed that the growth of wholesale prices of common and top-notch Sadri rice has been steadily increasing during the recent years (after 2007). Exponential function and the S-curve forms provided a better model for the time series procedures compared to the other forms. Holt-Winter multiple (HWM) algorithm was also the best nonparametric pattern for justifying the nature of behavior of the monthly time series of common and top-notch Sadri rice. Investigating the existence of seasonal unit roots revealed the similarity of the unit roots existence in the two studied time series. On the other hand, there was no long-term unit root in either of the two monthly time series of wholesale prices of common and top-notch Sadri rice at the 5% probability level.

With increasing world population and energy limitations, access to sufficient energy in the future will be difficult. Assessing the energy balance can be a scientific method to measure the stability and sustainability of an agroecosystem are considered. The objective of this study was to evaluate the energy consumption and economic analysis of irrigated wheat production in seven provinces of Iran including Alborz, Isfahan, Ardebil, Khorasan-e-Razavi, Khuzestan, Golestan, and Hamadan. Required information of this study was collected via questionnaires and face to face interviews with irrigated wheat farmers in the studied provinces. Then, using energy equivalence equations, input and output energies and energy indices were calculated. The results showed that the highest and lowest input energy were obtained from Khorasan-e-Razavi and Golestan provinces with 104701 and 26198.07 MJ.ha-1, respectively. Alborz and Khorasan-e-Razavi provinces had the highest and lowest output energy in irrigated wheat production with 162169.28 and 122297.53 MJ.ha-1, respectively. The maximum contribution of input energy for Alborz, Ardebil, Khuzestan, Golestan and Hamadan provinces was regarding to chemical fertilizers, while for Isfahan and Khorasan-e-Razavi was irrigation energy. Average input energy, output energy, energy ratio, energy productivity and net energy gain for all the studied provinces were 58308.83 MJ.ha-1, 136092.15 MJ.ha-1, 2.87, 0.212 kg.MJ-1 and 77783.31 MJ.ha-1, respectively. Agricultural machinery with 34.87% had the largest contribution of production cost. The highest and lowest energy productivity values were obtained from Golestan and Khorasan-e-Razavi provinces with 0.38 and 0.08 kg.MJ-1, respectively. The average benefit to cost ratio was 2.16 and the economic productivity index was 0.154 kg per 103 Rials. The results of current study showed that the production of irrigated wheat in the studied areas of Iran is justifiable in terms of economic and energy balance. Therefore, with respect to energy sustainability in production and conservation agriculture principles, it is possible to increase the cultivation area of irrigated wheat production.

To investigate the effect of slow-release fertilizer enriched with Fe on grain quality of Narin, a new wheat cultivar, under salinity conditions and assessing the allelic diversity of high molecular weight glutenin encoding genes, a factorial experiment was conducted as randomized complete block design with three replications in research greenhouse of Aburaihan Campus, University of Tehran, Pakdasht, Tehran, Iran, in 2017- 2018. The studied factors were two factors, salinity stress (at three levels including 0, 8 and 12 dS.m-1) and fertilizer (at five levels including no-fertilizer application, ferrous sulfate at 10 and 20 mg.kg-1 soil, super-absorbent fertilizer enriched with ferrous sulfate at 52.5 and 105 mg.kg-1 soil). The studied traits included 100 grain weight, grain yield per plant, grain protein percentage, grain Fe content, grain total soluble carbohydrates, grain hardness index, flour water absorption, moisture content, bread volume and zeleny sedimentation volume. The results showed that 100 grains weight, grain yield per plant, grain Fe content, grain total soluble carbohydrates content and zeleny sedimentation volume increased with application of fertilizer and superabsorbent fertilizer enriched with Fe had more positive effects than ferrous sulfate in many of the studied traits. Salinity stress significantly decreased 100 grains weight, grain yield and total soluble carbohydrates content, but grain Fe content, grain protein percentage and flour water absorption significantly increased with increasing salinity stress. By studying the electrophoretic pattern of high molecular weight glutenin subunits in Narin variety, 2*, 7+8 and 2+12 alleles were identified at Glu-A1, Glu- B1 and Glu-D1 loci, respectively. Based on the results of the present study, it seems that superabsorbent fertilizer enriched with Fe has higher efficiency than ferrous sulfate fertilizer on the qualitative characteristics of wheat grain and flour, especially under salinity stress conditions.

To investigate the effect of planting date on grain yield and phenological stages of some new bread wheat cultivars, a split plot experiment was conducted as randomized complete block design with three replications in Eslamabad-e-Gharb Agricultural Research Station, Kermanshah, Iran, during 2013-2015 cropping years. The studied factors included planting date at four levels (early, timely, late and very late) and wheat cultivar at six levels (Chamran-2, Parsi, Pishtaz, Bahar, Sirwan and Sivand) which were considered as main- and sub-plots, respectively. Based on the results, early, late and very late planting dates caused a decrease in grain yield by 19.34, 30.34 and 44.40 percent, respectively. The total growth period of wheat cultivation in early, timely, late and very late planting dates were 244, 222, 204 and 181 days, respectively. In early planting date, the traits of number of days to first leaf appearance, tillering, single ridge, double ridge, terminal spikelet and stem elongation was decreased, but after stem elongation stage, the studied cultivars had the highest number of days to flag leaf appearance, booting, heading, anthesis and physiological maturity. The cultivars "Bahar" and "Sirwan" had the highest and lowest values (2317 and 2155 growing degree days, respectively) during the growth period at all planting dates. Cultivar “Parsi” with 934 units in stem elongation and 807 units in grain filling period, had the highest and lowest growing degree days, respectively, and therefore due to early maturity (heading) and fine grain filling capability, had the highest grain yield (8097 kg.ha-1) in a total of four planting dates. Overall, the results of this study showed that early and late planting dates significantly reduced grain yield compared to timely planting in all studied cultivars. Therefore, planting in mid-November and using wheat cultivars such as "Parsi" and "Sirwan" can be recommended for similar climates of the studied region in this research.

Breeding for yield and yield stability has always been the main goal for breeders. In the current research, yield and yield stability of 51 wheat cultivars introduced over the last half century were evaluated in a randomized complete block design with two replications during five years. Analysis of variance revealed that genotype × environment interaction was significant. Therefore, the pattern of genotype × environment variation was analyzed using graphical method. According to the results of GGE biplot analysis, the first and second components as genotype and genotype × environment interaction components, explained 41.98% and 20.28% of the total variation, respectively. Simultaneous pattern of yield and yield stability divided the studied cultivars into three groups including desirable, moderate and undesirable. Among the studied cultivars, Mahdavi, Maroon and Sistan showed high yield and yield stability, while Shahpassand and Zagros had a low yield and yield stability. The results of this study showed that breeders have successfully introduced the genotypes with high yield and good stability over time, however due to the complexity of yield and yield stability traits, 10% of genotypes with low yield and 30% with poor stability have been introduced during 1986-2006, which confirms the need for more accurate tests in the future. Winter genotypes showed lower yield and yield stability compared to spring and facultative cultivars. Since, spring cultivars showed high yield in autumn cultivation, it is therefore recommended to cultivate spring cultivars in autumn as well.

To estimate gene action and heritability of yield and yield components of maize, F2 progenies derived from half-diallel cross of five S7 maize lines along with parental lines were assessed in a randomized complete block design with three replications at the Research Farm of Graduate University of Advanced Technology, Kerman, Iran, in 2017-18. The studied traits were grain yield and its components including number of ear per plant, number of grain per ear, number of grain row, number of grain per row, ear length and 100-grain weight. Results of analysis of variance showed significant differences among genotypes for all studied traits at 1% probability level. The results of Hayman’s graphical analysis also indicated that the contribution of non-additive gene effects was more important than additive effects in controlling most traits. Number of ear, number of grain per row and grain yield per plant were controlled by the incomplete dominance effects of genes, while the other traits were controlled by over-dominance effects. Broad sence heritability of the traits varied from 0.03 for number of grain row to 0.50 for 100-grain weight. The results of this study showed that both hybrid production and selection methods can be used to breed the number of ear, number of grain per row and grain yield per plant, but to breed the other traits in the studied population, the use of heterosis phenomenon and hybrid production is suggested.

Spot blotch caused by the fungal pathogen Cochliobolus sativus and is an important leaf disease of barley. To identify gene loci associated with seedling resistance to spot blotch in a population consisting of 142 modern European two-row spring barley cultivars, the genotypic data from 407 AFLP and SSR markers and phenotypic data derived from responses of barley cultivars to four isolates of spot blotch (Csh-1 and Csh-16 isolates from barley and Cst-42 and Cst-151 isolates from wheat) were used. These isolates were collected from Mazandaran, Golestan and Khorasan-e-Razavi provinces. The results showed that most of the studied cultivars at seedling stage were resistant to Csh-16 and Cst-42 isolates, but the highest number of susceptibility reactions to Csh-1 and Cst-151 isolates were observed. Population structure analysis subdivided the studied cultivars into two subpopulations (K=2). Association analysis using general linear model (GLM), six and twelve markers and using mixed linear model (MLM), three and four markers associated with resistance to isolates separated from barley and wheat leaves was identified, respectively, that were significantly to (P≤0.01). These QTLs were mapped on chromosomes 2H, 3H, 5H, 6H and 7H. All of the reported QTLs were specific for each isolate and only Bmag0225-161 marker was common between two isolates Csh-1 and Cst-151. The Identified markers can be used in breeding programs to develop disease resistant cultivars after validation.