فصلنامه تحقیقات غلات
سال دوازدهم شماره 2 (تابستان 1401)

The lack of irrigation water resources in the country in recent years has reduced the yield of crops and threatened food security; Therefore, it is necessary to think of ways to produce crops while saving water. One of the ways to increase production with limited irrigation water resources is the cultivation of drought-tolerant crops with high water use efficiency. Sorghum is known as one of the most important crops in arid and semi-arid regions of the world with its unique characteristics (including tolerance to environmental stresses, especially drought and heat, deep and extensive root system, C4 photosynthetic pathway, etc.). The use of appropriate irrigation methods is also known as another way to increase the production of crops with limited water resources. In this regard, the irrigation methods of alternate furrow irrigation and drip irrigation have been used as new irrigation management solutions in the country with favorable results. This study aimed to evaluate the effect of different irrigation regimes and methods on yield, morphological characteristics, water productivity, and drought tolerance of open-pollinated and hybrid forage sorghum cultivars.

This experiment was conducted as a factorial split-plot based on a randomized complete block design with three replications at the Seed and Plant Improvement Institute, Karaj, Iran, during the 2019 and 2020 cropping seasons. The factorial combination of four irrigation methods (CFI, conventional furrow irrigation; FFI, fixed alternate furrow irrigation; AFI, variable alternate furrow irrigation; and drip irrigation) and three levels of drought stress (full irrigation, moderate stress, and severe stress; including the supply 100, 75, and 50% of soil moisture deficit, respectively) as the main factor and two sorghum cultivars (Speedfeed and Pegah) as sub-factor were investigated. In this study, traits including silage yield, dry matter yield and percentage, irrigation water use efficiency, benefit per drop, net benefit per drop, leaf-to-stem ratio, plant height, and drought stress tolerance indices were evaluated. Due to the homogeneity of the variances of experimental errors over two years, the data were subjected to combined analysis of variance using SAS 9.1 statistical software, and Tukey's test (P≤0.05) was used to compare the means. In addition, IPASTIC online software was used to calculate stress tolerance indices and principal component analysis (PCA) based on these indices.
Research

The results showed that drought stress in all investigated irrigation methods decreased the silage yield, dry matter yield, and plant height and increased water use efficiency for silage and dry matter production, dry matter percentage, and leaf-to-stem ratio. The highest silage and dry matter yields (79.11 and 17.19 ton ha-1, respectively), and the maximum net benefit per drop (18854 Rials m-3) were obtained by cv. Pegah under full irrigation and drip method, whereas the maximum water use efficiency for silage and dry matter production (34.53 and 7.88 kg m-3, respectively) and the highest benefit per drop (60542 Rials m-3) were recorded in hybrid Speedfeed under severe stress and drip method. The highest leaf-to-stem ratio (0.715) was obtained in the FFI method under severe stress and the amount of this trait in cv. Pegah was about 8.6% higher than that of hybrid Speedfeed. Based on the stress tolerance indices, cv. Pegah under the CFI and drip methods and hybrid Speedfeed under the FFI method had more drought tolerance. In contrast, there was no significant difference between the cultivars under the FFI method.

In order to save water while achieving suitable forage yield and water productivity, the drip irrigation method and supplying 75% of soil moisture deficiency is recommended. If it is impossible to implement the drip irrigation system, the variable alternate furrow irrigation method can produce suitable forage yield while reducing the amount of water consumed.

IntroductionWater deficit compared to other abiotic stresses is the most important factor limiting the growth and production in all crops, especially wheat. Investigating the response of crop plants under stress conditions is the best way to produce drought-tolerant cultivars and improve yield under stress conditions. The challenge of breeding for drought stress tolerance in all crop plants, is to achieve a rapid screening method of genotypes and genetic improvement of yield under these difficult environmental conditions. The objective of this experiment was to identify high-yielding and water deficit tolerant genotypes in an F4 generation population of bread wheat.Materials and methodsThe plant materials of this experiment were 90 genotypes of the F4 generation resulting from a cross between two bread wheat cultivars (Arta, a spring cultivar sensitive to salinity and drought stresses, and Arg, a tolerant cultivar to salinity and drought stresses). These genotypes along with the parents, were evaluated in split plots based on randomized complete block design with three replications under two conditions (normal irrigation and non-irrigation from the pollination stage) in the research farm of Faculty of Agriculture, Tabriz University, Tabriz, Iran, in 2014. Evaluating the genotypes were done by simultaneous application of stress tolerance index (STI) based on yield-related traits including grain yield (STI-Y), spike weight (STI-S), 1000-grain weight (STI-1000) and harvest index (STI-HI) and identifying the relationship between these indices using genotype × trait biplot analysis. The studied genotypes were ranked based on the relationships in the biplot, and the high yield and water deficit tolerant genotypes were identified.Research findingsThe results of biplot showed that the first two principal components explained 72% (46% and 26%, respectively) of total variance in the studied population. Acute and closed angle between the STI-Y, STI-S and STI-HI vectors indicated a positive correlation between these traits, while the open and obtuse angle between the STI-Y and STI-HI traits with STI-1000 showed a negative correlation between them. In contrast, an quadrant angle was observed between STI-S and STI-1000 vectors, indicating that these two traits were independent and uncorrelated. In total, according to the relationships in the biplot and based on the combination of STI-Y and STI-1000 vectors, genotypes No. 84, 45, 89 and 15 were identified and introduced as the highest grain yield and most water deficit tolerant genotypes.ConclusionThe results of this experiment led to identification of superior and promising genotypes with higher yield potential and more tolerance to water deficit stress. Genotypes No. 84, 45, 89 and 15, which were superior to the stress-tolerant parent, after the purification steps, can be introduced as suitable genotypes for cultivation under water stress conditions as well as in normal environments. These genotypes can be used as drought tolerant parental lines in future breeding programs.

IntroductionProduction of high-yielding and stable cultivars is the most important objective of crop breeding programs, including wheat. The final yield of each plant is determined by the potential of genotype (G), the effect of environment (E) and the interaction effect of genotype × environment (GE). Several methods have been presented to study the genotype × environment interaction and determine stable genotypes, which can totally be divided into two main categories, univariate and multivariate. Univariate methods do not provide a complete view of the complex and multidimensional nature of GE interaction, therefore, the use of multivariate methods is suggested to solve this problem. Among the multivariate methods, AMMI and GGE-Biplot methods are more important. The objective of the current experiment was to investigate the interaction between genotype and environment for grain yield of 20 wheat genotypes and to identify stable and high-yielding genotypes.Materials and methods The plant materials of this experiment were 20 wheat genotypes including 18 irrigated wheat lines along with two control cultivars, Rakhshan and Baharan. The experiment was carried out in a randomized complete block design with three replications in five temperate regions (Karaj, Kermanshah, Zarghan, Boroujerd and Mashhad stations) during two cropping years 2019-2020. Two multivariate methods, AMMI and GGE-Biplot, were used to investigate the interaction effect of genotype × environment and to evaluate the stability of genotypes. R software was used to analyze the experimental data using the AMMI method, and Genstat software was used to analyze the data using the GGE biplot graphic method.Research findingsThe results of combined analysis of variance showed that the interaction effect of genotype × year and genotype × year × location were significant at the 1% probability level. Based on the results of AMMI analysis, the effect of environment, genotype and genotype × environment interaction were significant. Based on AMMI1 and AMMI2 models, AMMI stability value (ASV) parameter and genotype stability index (GSI), genotype 12 with an avearage grain yield of 8.27 tons per hectare was determined as the best genotype. The study of GGE-biplot polygon led to the identification of three mega-environments, that Boroujerd had the highest power of representation and differentiation among different environments. Genotypes 12 and 9, in addition to having high yield, had higher yield stability. Genotypes 12 and 9 were placed in the center of the circle as the ideal genotype and genotypes 5, 7 and 18 were ranked next. Based on the results of both methods, genotype 12 was identified as the most stable genotype.ConclusionThe results of AMMI, AMMI stability index (ASV) and genotype stability index (GSI) compared to GGE biplot results showed that all these indices have a good potential to evaluate the performance stability of genotypes. Nevertheless, GGE biplot results are more effective and practical in examining the compatibility and stability of genotypes' performance in different environments due to the ease of interpreting graphical results.

IntroductionRice is one of the most important grains and food items in the world, which is grown exclusively for humans and is the main food of half of the world's population. This important product plays a fundamental role in ensuring the country's food security and also the agricultural economy of Guilan province; Because every year more than 193 thousand farmers cultivate rice in the fertile and prone lands of Guilan province. Therefore, the aim of this research is to investigate the effective factors in achieving sustainable agricultural indicators in the production of rice in Guilan province, which can increase yield, create suitable opportunities, increase income and finally the relative well-being of Guilan rice farmers. This research was conducted in Guilan province and Rasht city in 2021-2022.Materials and methods The current study was conducted in Rasht city, Guilan province, Iran, in 2021-2022. The statistical population of this research was the rice farmers of Rasht city and the experts of agricultural jihad organization of Guilan province. Using Cochran's formula, the sample size of 383 rice farmers was calculated and 70 were selected for the statistical population of experts. Sampling of rice farmers was done in a multi-stage manner and the samples were randomly selected from each village and the sampling of experts was done by full count. The main tool for collecting the information required for this research is a researcher-made questionnaire, the validity of which was confirmed by 10 university professors and experts of the agricultural Jihad organization, and its reliability was obtained using Cronbach's alpha, 0.81. The research variables were divided into five different categories, including managerial, economic, ecological characteristics, use of technology and social participation, and their effect on achieving sustainable rice cultivation in Gilan province was investigated.Research findingsThe most important research findings in the descriptive statistics section showed that the education level of about 40% of the statistical population of this research is a diploma. 54% of the rice farmers own their paddy lands and the average area under rice cultivation of the farms in this research is 1.1 hectare. In addition, the rate of satisfaction of rice farmers with rice cultivation is 67.7%. The results obtained from the analytical statistics also showed that the studied characteristics in this research had a different effect on achieving sustainable agriculture in rice production, so that managerial and economic characteristics had high influence from the experts opinion and moderate influence from the rice farmers opinion, technological features and innovation had high influence from the experts viewpoint and low influence from the rice farmers viewpoint, ecological characteristics had moderate influence from the viewpoint of both rice farmers and experts, and the characteristics of social participation also had loe influence from the viewpoint of both rice farmers and experts. The comparison between the viewpoint of two statistical populations studied in this research (rice farmers and experts) based on the t-test also showed that there was a significant difference between them in terms of achieving sustainable agricultural indicators, so that the studied variables in this research had a high influence from the viewpoint of most experts but a moderate influence from the viewpoint of most farmers.ConclusionIncreasing knowledge and improving attitude will improve performance and create relatively stable changes in behavior and enable the target groups to quickly adapt to environmental changes. Knowledge is the driver of change and improvement in the attitude of rice farmers in relation to the indicators of the correct method and time of plowing, the minutes of plowing, the construction of modern warehouses, the correct amount of seeds to use, etc. in sustainable rice cultivation. Examining the economic characteristics of rice farmers also showed that by improving the efficiency of existing facilities and capital, increasing production efficiency, reducing costs, increasing knowledge, improving technical skills, etc., in the economic status of rice farmers desirable changes are made. As a result, if the rice farmers have a favorable economic situation, along with receiving loans and necessary government credits, they can achieve many indicators of sustainable development of rice production and take steps in the direction of balanced national development. In addition to the economic characteristics, the use of ecological power that is accompanied by scientific and correct management, while it makes the realization of many goals of sustainable rural development, achieves the goals of balanced and sustainable development at the national level, makes it possible and gives it a double speed. One of the important and effective characteristics in achieving sustainable agriculture is the use of new technologies. New technologies bring the use of new findings, and the use of new technologies requires economic power to acquire the new technology. Another important finding obtained from this research is that no rural development plan will go anywhere without paying attention to the participation of the people. Identifying and compiling a suitable model for the participation of villagers to achieve sustainable agricultural indicators, sustainable rural development, followed by balanced sustainable national development, is a necessary and undeniable matter.

IntroductionEnvironmental stresses such as nutrients deficiency stress are serious threats to agricultural products. Zinc is one of the low-consumption essential nutrients but with high nutritional value, which plays an important role in root growth, increasing yield, plant resistance to diseases, photosynthesis, cell membrane integrity, pollen formation, energy production and increasing antioxidant enzymes and chlorophyll in plant tissues. Furthermore, zinc is essential for production of plant hormones such as abscisic acid, auxin, gibberellins and cytokinin, and its deficiency causes disruption in plant cell reprodution. Wheat grain contains zinc about from 20 to 30 mg/kg. About 50% of the soils used for cereal production in the world do not have enough usable zinc. One of the strategies to compensate for zinc deficiency is to improve zinc-efficient cultivars. Therefore, it is necessary to conduct basic research to identify the genes controlling zinc. In the current research, 64 spring wheat cultivars were studied under normal and zinc deficiency stress conditions, and the objective of this experiment was to identify genomic locations controlling phenological, physiological and biochemical characteristics using LD-based GWAS method based on SNP markers.Materials and methods To genome-wide association study of yield and physiological and biochemical traits in Iranian bread wheat varieties, 64 varieties of spring wheat were cultivated as a pot experiment in a simple lattice design under two normal and zinc deficiency stress conditions in the research farm of Faculty of Agriculture, Urmia University, Urmia, Iran. The studied traits include days to germination, days to booting, days to pollination, days to physiological maturity, grain filling period, canopy temperature, total chlorophyll, leaf area index, fresh and dry shoot weight, relative water content, shoot zinc concentration, grain protein concentration and grain yield. Genotypic evaluation of the population was performed using 36360 SNP markers. To determine the population structure, principal component analysis (PCA) was used and PCA results were considered as covariate variables instead of the Q matrix for association analysis. For association analysis and identification of linked markers to the genes controlling the studied traits, GLM and MLM methods were used and significant marker-trait associations (MTAs) were separately identified for each of the experimental conditions. Research findingsThe results of association analysis using the GLM method identified 145 marker-trait associations (MTAs) under normal conditions and 135 MTAs under zinc deficiency stress conditions, while using the MLM method, 165 and 142 MTAs were identified under normal and zinc deficiency stress conditions, respectively. The highest and lowest number of significant marker-trait associations with both GLM and MLM methods under normal conditions were identified for dry weight and grain filling period, respectively, while under zinc deficiency stress conditions, the highest number of significant MTA with both association analysis methods was observed for leaf relative water content and the lowest number of MTA was observed for grain protein content and shoot zinc concentration. Identified markers can be used in breeding methods such as selection with in breeding programs. The significant marker-trait associations (MTAs) identified in this experiment can be used to increase the efficiency of breeding programs using the marker-assisted selection.ConclusionThe results of the present study showed the efficiency of the association analysis method as well as the GLM and MLM models in identifying markers linked to evaluated traits in wheat. The information obtained from this experiment also showed that SNP markers are a powerful tool for evaluating genetic diversity and preparing the structure of wheat populations and can be used in breeding programs via marker-assisted selection. Although, it is necessary to investigate the markers identified in larger populations to ensure their relationship with the studied traits. In this study, several common and similar gene loci were also identified for the studied traits, which can be used for the simultaneous multi-traits selection in future breeding programs.

Soil salinity, as one of the most important environmental stresses, is a serious threat to agricultural production. Currently, more than 20% of the agricultural lands, which includes 954 million hectares of the world's lands, is affected by soil salinity. Salinity is expanding daily and it is predicted that by 2050, more than 50% of the world's arable lands will be saline. The decrease in yield due to salinity stress in wheat is considerable and worrying, so that a 50% decrease in yield of durum wheat due to salinity of rainfed lands, and an 88% decrease in yield of bread wheat under irrigation with high salinity and and a 70% decrease in yield of bread wheat in sodic soils has been reported. The high levels of salt in soils and irrigation waters are worrying factors for agriculture, therefore it is necessary to develop the effective strategies to improve yield through salinity stress tolerance. The present study was carried out due to the importance of genetic accessions as sources of tolerance to biotic and abiotic stresses including salinity, and the existence of considerable genetic diversity in wheat germplasm to salinity stress tolerance. The objective of this experiment is to investigate the diversity of genetic accessions of bread wheat collection of Iran's National Plant Gene Bank, to compare the accessions with the tolerant control varieties, and to identify the new genetic resources for salinity tolerance.

To identify the genetic resources of salinity tolerance in wheat germplasm, 512 accessions from the bread wheat collection of the National Plant Gene Bank of Iran along with salinity tolerant varieties, Kavir, Roshan and Mahoti as controls, were investigated in two different augmented designs under normal and salinity stress conditions. The normal experiment was carried out at the research field of Yazd Research Center and the salt experiment was done at saline lands of Ardekan Research Station. The studied traits included spike length, spike density, 100-grain weight, number of tillers, plant height, number of spikelets per spike, number of florets per spikelet, number of grains per spike, days to heading, days to maturity, grain filling period and grain weight of five spikes,  which were recorded according to the international description. To perform data statistical analyses, descriptive statistical indices were first calculated and then the studied accessions were grouped using K-means cluster analysis. Discriminant function analysis based on principal components was used to investigate the differentiation between the groups resulting from cluster analysis. Statistical analyzes were performed by SPSS and R softwares.
 
 
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The results showed that grain weight of five spikes (with a minimum of 4.15 and a maximum of 12.26 g in normal conditions and a minimum of 2.19 and a maximum of 9.78 g in stress conditions) and the number of spikes (with a minimum of 3 and a maximum of 8 in normal conditions and a minimum of 3 and a maximum of 7 in stress conditions) had the highest coefficients of variation, while days to heading (with a minimum-maximum of 130-163 days and 126-168 days in normal and salinity stress conditions, respectively) and days to maturity (with a minimum-maximum of 173-189 days and 168-196 days in normal and salinity stress conditions, respectively) had the lowest coefficient of variation under both normal and salinity stress conditions. A large number of superior accessions were identified for various traits compared to the control cultivars under both normal and salinity stress conditions. The results of stepwise regression indicated the importance of three characteristics, 100-grain weight, number of grains per spike and number of florets per spikelet, in describing the variation of grain weight of five spikes. The investigated accessions were divided into five groups using K-means cluster analysis and the control cultivars were separated into different groups so that Roshan and Mahooti along with 70 accessions were grouped in the first cluster and Kavir along with 53 accessions in the fifth cluster.

The results of this experiment showed the presence of significant and valuable genetic diversity in traits related to salt stress tolerance in the studied bread wheat germplasm. The effect of salinity stress on different traits of the studied accessions was different. Among the studied traits, 100-grain weight, number of grains per spike and number of florets per spike were more important, so they can be used in breeding programs. A large number of accessions were also superior to control cultivars for various traits. Cluster analysis grouped the control cultivars into distinct clusters, which indicates different aspects of salt stress tolerance in these cultivars. The superior accessions identified in this research can be used to improve salt stress tolerance in bread wheat breeding programs.