نشریه پژوهش های کاربردی زراعی
پیاپی 136 (پاییز 1401)

Agricultural ecosystems are a type of ecological systems where functions are organized in the direction of agricultural products and the characteristics of their production are determined based on the consumption of external inputs. In agricultural ecosystems, with monoculture of one cultivar and the excessive use of chemical inputs, crop yields are substantially increased. But the main challenge facing agriculture today is the environmental pollution caused by the use of chemicals and reduction of yield stability. Diversity in the selection of crop plant genotypes by farmers reduce production risk and annual yield fluctuations. Increasing genetic diversity through mixed cultivation of different cultivars or species with different morphological and physiological characteristics make possible use of the environment and resources. One of the ways to improve the quality and stability of wheat production is to increase the genetic diversity in the cultivation systems based on the mixed cultivation patterns. In Iran, excessive use of nitrogen fertilizers in agricultural ecosystems, especially in wheat production systems, is a problem, and it seems that increasing the efficiency of using this input is a very effective way to deal with this problem. The purpose of this research was to investigate the effect of increasing genetic diversity through intercropping of wheat cultivars on the efficiency of nitrogen and water use.

In order to evaluate the effect of increasing the genetic diversity of mixed cultivation of wheat cultivars on improving the efficiency of resource use, an experiment was carried out in the form of completely randomized block design with 3 replications in the research farm of Agriculture Faculty of Ferdowsi University of Mashhad in two crop years 2018-2019. Treatments included pure cultivation and double, triple and quadruple mixtures of four varieties of wheat, Heydari, Pishgam, Pishtaz and Falat, which were introduced in the 60s, 70s, 80s and 90s, respectively, and were in the same maturity group. The amount of absorbed nitrogen, absorption efficiency (NUpE), conversion efficiency (NUtE), nitrogen use efficiency (NUE) and water productivity. The data of the two-year test was compiled using Minitab software ver. 18.0 variance analysis was carried out and Excel software was used to draw graphs.

The results of the experiment showed that there was a significant differences in terms of water consumption efficiency, the amount of absorbed nitrogen, consumption efficiency and nitrogen absorption efficiency for pure and mixed cultivation of different wheat cultivars, but no significant difference observed for nitrogen conversion efficiency (p≤ 0.05). The highest amount of absorbed nitrogen, utilization efficiency, absorption efficiency and nitrogen conversion efficiency were observed for mixed cultivation of Pishtaz + Heydari cultivars (99.1 kg/ha, 34.5%, 69.3%, 49.8%), Pishtaz with Heydari and Falat (111.1 kg per hectare, 36.6%, 78.2%). While the highest water consumption efficiency was achieved for pure and mixed cultivars, respectively, Pishtaz (0.9 kg/m3 water), Pishtaz + Heydari (1.4 kg/m3 water), Pishtaz with Pishgam and Heidari (1.3 kg/m3 water). Water productivity showed a positive and significant correlation with absorption efficiency and nitrogen use efficiency (R2= 0.71, R2= 0.68). Thus, with the increase of nitrogen absorption and consumption efficiency, water consumption efficiency also increased, while no significant correlation was observed between water consumption efficiency and nitrogen conversion efficiency. According to the results of this research and the experiments result of other researchers, it can be said that through mixed cultivation and increasing the genetic diversity of wheat cultivars, the amount of absorption, the absorption efficiency and the efficiency of nitrogen consumption can be improved.

The results of this experiment showed that, by increasing genetic diversity through double and triple mixed cultivation of wheat cultivars, nitrogen efficiency and water consumption improved. In terms of water consumption efficiency, the amount of absorbed nitrogen, consumption efficiency and nitrogen absorption efficiency, there was a significant difference for the pure and mixed cultivation of different wheat cultivars, but no significant difference was observed for the nitrogen conversion efficiency. The highest amount of absorbed nitrogen, utilization efficiency, absorption efficiency and nitrogen conversion efficiency were belonged to the mixed cultivation of Pishtaz + Heidari cultivars, Pishtaz + Heidari + Falat. While the mixture of Pishtaz + Heidari, Pishtaz + Pishgam + Heidari had the highest water productivity.

Barley (Hordeum vulgare L.) with a cultivated area of nearly one and a half million hectares and with a production of about three million tons per year after wheat is the main crop in the country. Of this amount, about 600,000 hectares with a production of approximately two million tons are related to irrigated barley and about 900,000 hectares with a production of approximately one million tons are related to dryland barley (Ahmadi et al., 2020). In recent years, the shortage of barley production has been felt more than ever and in the comprehensive plan of the country's fodder, It has planned to increase its production in the long run. Similar to other crops, insufficient yield stability in barley is recognized as a one of the factors responsible for the gap between actual yield and potential yield (Cattivelli et al., 2008). In breeding programs, the identification of superior genotypes is difficult due to environmental variability of target locations and the interaction of these variabilities with the investigated genotypes. Therefore, it is important to evaluate the advanced agronomic lines across various environments and over multiple years to ensure their yield stability and production (Yan & Rajcan, 2002). The main objectives of this study were to evaluate grain yield stability and adaptability in some promising barley lines and characterization of barley inbred lines based on multiple traits under irrigation conditions.

Nineteen promising barley lines (G1-G19) along with one check cultivar (Behrokh), were studied during 2016-2019 at Nishabour Agricultural Research Stations. The experimental design at was a randomized complete block with three replications. Several main traits i. e., days to heading, days to maturity, plant height, thousand kernel weight and grain yield were recorded for all genotypes. GGE biplot and genotype by trait (GT) biplot methods were used to yield stability assessment of genotypes and characterization of barley inbred lines based on multiple traits.Combined analysis of variance for grain yield and other traits was analyzed using ADEL-R software. The GGE biplot and GT biplot methodologies were employed to analyze GxE interaction and characterization of barley inbred lines based on multiple traits using GEA-R software (Yan, 2001).

The yield combined analysis of variance showed that the effects of year, genotype and genotype×year were significant at 1% probability level. The results also showed that approximately 23.45% of total variance was appertained to year effect, 30.72% to genotype effect and 21.37% to genotype × year interaction. Whole the mean grain yield of the evaluated lines in all years varied from 4.446 to 6.946 ton /ha and the G17 and G12 lines had the lowest and highest grain yield, respectively. Based on the biplot of average-environment coordination (AEC) for simultaneous selection of grain yield and stability of barley genotypes, genotypes G12 and G3 with the high grain yield were the most stable genotypeS. According to resulting from biplot of barley promosing lines in comparison with ideal genotype, G12 and G3 were identified as the ideal genotype. Also the closest genotypes to them were G9, G11, G15 and G16. Based on GT-Biplot polygon, G12, G3 and G9 lines were displayed high grain yield, grain filling period and lowest days to heading. The vector view of GT biplot showed high positive correlation between grain yield with grain filling period and negative correlation with days to heading. The high heritability along with advance genetic for the grain filling period, days to heading and plant height is encouraging from a standpoint of increasing the selection efficiency. In conclusion, the GT biplot offers a useful analytic tool for examining the variation among sets of lines, for exploring multiple trait data and for aiding in multi-trait selection.

It was found that the genotypes with the highest grain yield had high the duration of the grain filling period, early in flowering time and Medium to low plant height under irrigated conditions. Based on the results, lines G12, G3 and G9 were the most stable high-yielding genotypes that had high duration of the grain filling period and thousand kernel weight, early in flowering time and low plant height in Nishabour condition.

Rapeseed is a main oilseed crop in the world. Water deficiency is the main cause of reduced crop yield under drought stress. The highest rapeseed yield reduce was resulted when water deficit occurred at flowering and pod developmental stages (Kahrizi and Allahvarand, 2012). Knowing about the traits that affect grain yield, so that by improving these traits, grain yield can be increased, plays an important role for being successful breeding programs. Factor analysis of multivariate statistical methods is for a deeper understanding of the relationships between traits and is an effective statistical method in reducing data volume (Cooper, 1983). The aim of this study was to study the effect of late-season drought stress on some traits affecting the yield of studied rapeseed genotypes and to identify genotypes compatible with normal and drought stress conditions using some stress tolerance indices.

This experiment was carried out at the research field of Seed and Plant Improvement Institute, Karaj, Iran, on 2016-2018 growing seasons under full irrigation conditions and late-season drought stress (from beginning pod setting stage) on new winter rapeseed genotypes in a randomized complete block design with three replications. Some of morphological, physiological, phenological traits, yield and yield components were measured. Factor analysis was performed to determine the most influential variables. To identify drought tolerance genotypes, drought tolerance indices such as tolerance index (TOL), stress susceptibility index (SSI), mean productivity (MP), geometric mean productivity (GMP), harmonic mean (HMP), stress tolerance index (STI), Yield index (YI), Sensitivity drought index (SDI) and yield stability index (YSI) were used.

The combined analysis of variance showed that the effect of drought stress on all evaluation traits was significant except for height of the first branch, days to end of flowering, flowering period and oil percentage. The results showed that drought stress decreased Grain yeald, Pods per plant, Seeds per pod, 1000 Seed weight, plant height, Chlorophyll a and b, Cartenoid, Relative water content and Days to maturity; while it increased Chlorophyll Index (SPAD).The results of factor analysis exhibited three factors in normal and drought stress conditions, which explained 79.7% and 82.51% of the variation, respectively. This factors in normal conditions were named "Yield", "Plant pigment", "Phenological traits" respectively, and in stress conditions were named " productivity", "Plant pigment" and " sink" , respectively. It seems that its seams possible to use these traits as selection criteria in breeding programs for improve grain yield of winter rapeseed genotypes results showed that GMP, MP, HMP and STI indices were positively correlated with grain yield under both stress and non-stress conditions. Therefore, they can be exploited not only to screen drought tolerance but also to identify superior genotypes for both stress and non-stress field conditions (Fernandez, 1992). Principal component analysis using grain yield under both conditions and drought tolerance indices showed that the genotypes Nafis, Vesuvio, Medea, HL3721 and HL2012 were the most tolerant genotypes to drought conditions, while the genotypes Extorm, Excalibur, Danube and Expower were the most sensitive genotypes. With cluster analysis using WARD procedure based on drought tolerance, the studied genotypes were grouped in 3 separate clusters. The first group consisted of genotypes that have high yield and drought tolerant and had appropriate and reliable values of indices such as STI, MP, GMP, HMP. Therefore, this group (genotypes Nafis, Vesuvio, Medea, HL3721 and HL2012) are drought tolerant group. The second group had genotypes with low values of STI, MP, GMP, HMP as well as Ys and Yp and higher values of SSI. Therefore, genotypes Danube, Excalibur, Expower, Harnus and Extorm with low yield and drought sensitivity were placed in this cluster. The next group (Okapi, Ahmadi, Nima, Natalie, SLM046, Artist) with average yield in both non-stress and stress conditions, and less sensitivity to drought stress condition, were stable in yield, and therefore considered as semi-resistant cultivars.

The study of phenotypic diversity is highly recommended as a first step before conducting in-depth biochemical or molecular studies. Hence, morphological description is the most important issue in the process of studying and preserving plant genetic diversity. The use of different traits to study phenotypic diversity reveals the genetic structure and degree of diversity of the study population, which forms the basis of genetic breeding. In breeding programs with the aim of improving the crop and increasing productivity, recognizing the genetic diversity associated with important agronomic traits and also determining the relationship between them is of particular importance.

In this regard, 155 sugar beet hybrids were planted in five incomplete blocks in Khoy Agricultural Research Station during 2020 in the augmented randomized complete block design with five controls of Sina, Novodoro, Modex, Lorquite and Pirula. Germination uniformity and growth uniformity were recorded during the growing season. Experimental harvesting operation was performed by counting and weighing the roots of experimental plots. The roots were then transferred to the sugar technology laboratory of Khoy Agricultural Research Station to wash and prepare a random sample of pulp. To estimate sugar yield, first the root yield of each hybrid was generalized per ton per hectare and by multiplying the percentage of sugar and root yield, sugar yield was obtained. Phenotypic, genetic and environmental variances, phenotypic, genetic and environmental variation coefficients, general heritability and genetic advance were calculated. After calculating Pearson correlation coefficients between the studied traits, stepwise regression analysis was performed for sugar yield characteristics; Then, according to the traits entered in the regression equation, path analysis for sugar yield was performed. Experimental genotypes were grouped based on the Ward method and the optimal number of clusters was determined based on k means.

The results of analysis of variance of the studied traits indicated that there was significant genetic diversity among experimental hybrids in terms of germination uniformity, root yield, sugar content and sugar yield. In all studied traits, due to the influence of environmental factors on them, the phenotypic diversity coefficient was estimated to be higher than the genetic diversity coefficient. Four traits of germination uniformity, root yield, sugar yield and sugar content showed high inheritance. Among the different studied traits, sugar yield and root yield had a positive and a very significant correlation at the probability level of 0.1%. The results of stepwise regression analysis confirmed that the three traits of root yield, sugar content and germination uniformity cause more than 99% change in sugar yield. The results of path analysis confirmed the results of correlation analysis and stepwise regression and showed that the most direct and positive effect is related to the root yield. Based on cluster analysis, experimental hybrids were classified into four distinct groups; So that in the first group was hybrids that had high uniformity in germination and good yield in terms of roots and sugar.

Genetic diversity is now accepted as a special field that can contribute to food security and nutrition. Genetic diversity of crops is the basis of sustainable development. Therefore, there is a need to identify diverse genetic resources using various statistical tools and use them in breeding programs. In the present study, genetic diversity in terms of different traits among sugar beet hybrids was investigated using statistical methods. The results showed that there was considerable genetic diversity among the experimental hybrids in terms of the majority of traits, which confirms the extensive genetic variation in breeding hybrids and provided the paternal basis of this rich diversity in the studied germplasm; Experimental hybrids were divided into four heterotic groups for all traits. Given the diversity of traits and experimental hybrids, hybrids with desirable traits can be selected based on breeding goals and used in future breeding programs to achieve the goals.

Sesame (Sesamum indicum L.) is an annual plant belonging to the Pedaliaceae family with a long agricultural history, which is mostly grown as an oil crop in tropical regions and is resistant to drought stress. This Crop is grown in Iran on an area of about 42,000 hectares with an average yield of 690 kg per hectare. The knowledge of the relationship between crop traits and performance is of great importance in agronomic research. Selecting the desired cultivars and determining the cause and effect relationships between traits allows the breeder to select the most appropriate plant traits to increase yield.

In this experiment, 12 sesame genotypes including commercial, local cultivars and line were evaluated. The experiment was conducted in the research farm of the Faculty of Agriculture of Persian Gulf University, Bushehr, located eight kilometers southeast of Barazjan city. The agricultural climate of the region has very hot, dry and long summers. The experiment was conducted in a randomized block design with three replications. Principal Components Analysis and Factors Analysis were used for reduction of data dimensions and better and easier interpretation of data and determination of hidden factors affecting performance.

All studied traits were statistically different. The highest amount of 1000 seed weight belongs to Behbahan (3.4 gr), Abadan (3.36 gr) and Dashtestan 2 (3.3 gr) landraces. The highest number of seeds per capsule, Plant height, number of branches and number of fertile branches were observed in Abadan, Dashtestan 5, Dashtestan 2 and (Barazjan and Abadan) genotypes, respectively. Abpakhsh, Ardakan Yazd, Barazjan and Dashtestan 5 landraces had a number of days to maturity than the others. This trait had high heritability and low genetic advances. In order to reduce the dimensions of the data, better and easier interpretation of them and to determine the hidden factors, Factor Analysis was done with varimax rotation. Three factors were extracted. According to the amount of influential traits in each factor, the first, and second factors were named yield potential and morphologic, phenology factors, respectively. In general, it can be concluded from the results that the yield and phonological traits can be important indicators for the evaluation and selection of sesame cultivars. According the Principal Components Analysis based on the correlation matrix ,76% of the total variations were estimated by three main components. As a result, it can be said that the selection based on the first component will lead to the genotypes with high yield, and the selection based on the second component will lead to the genotypes with late maturity characteristics. In order to determine the grouping of genotypes, cluster analysis was used and based on the three indices RMSSTD, False T2 and False F, four distinct groups were recognized. The results of cluster analysis did not show any relationship between the geographic and genetic distribution of genotypes.

The results showed that the studied genotypes were different according the studied traits. Because selection of genotypes with high yield is considered important in plant breeding programs, genetic parameters were calculated. The high level of genetic improvement and heritability for the traits number of capsules per plant, number of seeds per capsule, seed yield, number of fertile branches and harvest index indicate the possibility of selection with an intensity of 5% in the next generation of selection. The results of Factor Analysis indicated the importance of yield and phenology traits in the selection of desirable genotypes in sesame.

Carbon sequestration is the ability of plant biomass and the soil to absorb atmospheric carbon dioxide and store it for a long time. Therefore, carbon sequestration occurs when the rate of absorption of carbon dioxide by plants from the atmosphere, is larger than the total soil respiration rate, plant respiration and plant biomass cut (Anderson et al., 2008). Today, agriculture is effective in carbon sequestration through as an important factor in in order to mitigate the effects of climate change. In the past, carbon sequesters are mainly raised in relation to forests. But today, crops production or animal husbandry can also be effective by maintaining plant residues and proper consumption of organic fertilizers obtained in soil in carbon sequestration (Seyedi, 2016). Therefore, this study was conducted in order to evaluation the carbon sequestration potential in canola plant tissues in agroecosystems Sorkhankalateh region, Gorgan county.

This study was conducted to evaluation the carbon sequestration potential in above- ground and below ground tissues of canola (Brassica napus L.) in agricultural lands of Sorkhankalateh region (Gorgan County) during 2021-2022. In this study, 50 canola fields were selected and sampling from the fields based on the W pattern in the four geographical directions of the region. An electric burn furnace method was used to determine the conversion coefficients of carbon sequestration potential in above- ground and below ground tissues (including siliques, seeds, stems, leaves and roots). As well as, the ratio of above- ground to below ground tissues and harvest index were estimated to determine the net primary production based on carbon content in the above ground tissue, below ground and total plant, and the carbon allocation coefficients in each of the canola plant organs. Finally, using the ArcGIS software version 10.3, the amount of carbon sequestration potential in each of the canola organs was presented in the form of a map, and all the data used were analyzed using SAS software version 9.3.Results and DiscussionBased on the findings of this study, the average deposited carbon in total plant tissues in under cultivated fields of Hayola 50 cultivar was equal to 6657.47 kg per hectare and in under cultivated fields of Trapper cultivar equal to 6560.33 kg per hectare. So that the average carbon sequestration potential was obtained in the stem in two Hayola 50 and Trapper cultivars equal to 2012.36 and 1993.97, in seed 1717.20 and 1639.95, in pod 1676.77 and 1608.36, in leaf 602.90 and 615.72, and in root 648.21 and 703.30 kg per hectare, respectively. Also, the shares amount of the allocation coefficient of each of the economic tissues, stem, leaf and silique, root and root secretions were obtained, in two Hayola 50 and Trapper cultivars equal to 21.17 and 20.42, 63.60 and 63.49, 9.22 and 9.74, and 5.99 and 6.33 percent, respectively. In this study, the average total carbon sequestation potential in above- ground and below ground tissues was equal to 6610.86 kg per hectare. The highest and lowest carbon sequestation potential was obtained for stem with 2081.35 kg per hectare and leaf with 759.89 kg per hectare, respectively. Also, in the survey of carbon sequestration in above- ground and below ground tissues in canola fields, it was determined that there was a significant difference in 99% level. The results of carbon sequestration maps showed that there was the highest carbon sequestration rate in the fields located in the west and northwest, and carbon sequestration rate was lower in the fields located in the southern and eastern regions.