Appropriateness of farmers’ adoption of irrigation methods: The application of the AHP model

This paper explores the use of analytic hierarchy process (AHP) for selecting an appropriate irrigation method. A sample of farmers was separated into four groups using cluster analysis. A panel of experts utilized AHP to determine the priority of three irrigation methods (border, basin and sprinkler) for each group of farmers. The findings indicated that the highest priority of irrigation methods differed with respect to farmers groups. The appropriateness of the decision of each farming group, regarding selection of irrigation methods, was determined. In 74% of cases, experts confirmed the farmer’s decision in selection of irrigation methods, but questioned the appropriateness of the decision for 26% of farmers. Recommendations are made for future use of decision tools to improve extension programs and farmers decision-making process.     

Molecular aspects of drought tolerance in bread wheat (T. aestivum)

In order to evaluate molecular indices of drought tolerance and selection of drought tolerance genotypes in bread wheat a randomized complete block design was carried out with three replications in the field of research station of Sararood, Kermanshah, Iran. Positive significant correlation coefficient was observed between grain yield and proline, soluble sugar and total protein under rainfed condition. Based on the grain yield, proline content, soluble sugar and total protein the genotypes were classified into four clusters using cluster analysis and UPGMA method. Genotypes numbers 4, 9, 10, 11, 18 and 19 in the first clusters indicated the highest performance.     

Climate change and agriculture: Impacts and adaptive responses in Iran

The impacts of climate change on agriculture are still shadowed with uncertainty. However, climate change is expected to adversely affect Iran's agricultural practices through changes in precipitation, temperature and carbon dioxide fertilization. Therefore, adaptation of this sector to the increasing weather events is imperative. This study is aimed to document the likely impacts of climate change on Iran's agriculture and the current adaptation efforts made by government and farmers. The review of literature shows that changes in rainfall and water endowments will have significant impacts on crop yield, crops' water requirements and income and welfare of farm families. The extent of the changes in yield depends on the crop type, assumptions related to the CO₂ fertilization effect, climate scenarios and adaptation abilities. On adaptation, the government's efforts have been distinguished in the improving agricultural productivity and irrigation development based on current technology, developing new technologies and policy reforms. Farmers' adaptive responses have also been identified. Some conclusions and recommendations are offered to increase the adaptive capacity of farmers and reduce negative impacts of climate change.     

Genetic distance between Triticum timopheevi Zhuk., T. aramticum Jakubz. and T. aestivum L.

The genetic distances between two cultivated wheat (Triticum aestivum L.) varieties (Martonvásári 9, Martonvásári 15), a Martonvásári 9 line possessing the crossability gene krl, and 21 accessions of T. timopheevi Zhuk. and T. araraticum Jakubz. were estimated, based on agro-morphological, physiological and biochemical analysis of data. Cluster analysis based on Mahalanobis' D² values was applied. All 21 accessions of T. timopheevi and T. araraticum could be classified into eight clusters. Clusters I and II consisted of all the T. timopheevi, while T. araraticum was located in six clusters. Discriminant analysis was applied to test significant differences between cluster pairs. The genetic distance (GD) based on the electrophoretic data of gliadins indicated two types of electrophoregrams in T. timopheevvi, distinguished as groups A and B. T. araraticum accessions were variable as regards the spectra. Mean, minimum and maximum GD were estimated within and between different wheat groups based on acid polyacrylamide gel electrophoresis.     

Substitution analysis of drought tolerance in wheat (Triticum aestivum L.)

Chromosome substitution lines of the wheat variety ‘Cappelle Desprez’ into ‘Chinese Spring’ were tested for drought tolerance in growth chambers in the Martonvásár phytotron. Three different moisture regimes were created: E1, fully irrigated control; E2, mid-season water stress (preanthesis); and E3, terminal water-stress during grain filling. Data were analysed to estimate the chromosomal location of the genes controlling relative water-content (RWC), relative water-loss (RWL), drought-susceptibility index (DSI) and phenotypic stability in each substitution line. Simultaneous consideration indicated that most of the genes controlling these characters are located on chromosomes 1A, 5A, 7A,4B, 5B, 1D, 3D and 5D.     

Vulnerability and Adaptation of Livestock Producers to Climate Variability and Change

Rangeland-based animal husbandry has been frequently exposed to the vagaries of weather. While the current rates of climate variability are unprecedented in arid and semiarid regions, climate change is expected to put further pressure on rangelands with medium- and poor-quality forages and increase the vulnerability of households who mainly depend on livestock production. Therefore, it is imperative to ensure that livestock producers increase their resilience to climate variability or change. However, few field-based studies have focused on simultaneous investigation of both vulnerability and adaptation of livestock keepers to climate-related risks. To fill this gap, a field-based research study was conducted in southwest Iran. A survey of 274 herder families, selected using a cluster sampling technique, revealed low, medium and high levels of vulnerability, which were principally distinguished by various degrees of exposure, sensitivity, and adaptive capacity. Further, this study identified the main adaptation strategies employed by the herders of this region (i.e., purchasing fodder; rotational grazing; raising a mixed-herd, on-farm occupation; and postharvest grazing). Results indicated that most herder families applied traditional adaptation strategies in response to climate variability. Findings revealed that herders had to reduce their livestock due to low adaptability. Loan term, purchasing insurance, level of exposure, income, experience, response efficacy, and knowledge were the major determinants of the herders’ adaptation decisions. To increase the resilience of livestock producers against climate change, restructuring traditional livestock production systems, producing participatory knowledge and information for sustainable management of rangelands, and designing or redesigning effective adaptation strategies are required.     

Grazing intensity and environmental factors effects on species composition and diversity in rangelands of Iran

The aim of this study was to analyze the effects of grazing, precipitation and temperature factors on plant species dynamics (diversity and composition) in the semi-steppe of Isfahan semi-arid rangelands, Iran. The effects of Sheep grazing were studied in a controlled experiment along grazing gradient with seven intensities (from very heavily grazed to nongrazed) during six consecutive years (2006–2011). The results show that plant species dynamics varied among years, but were only slightly affected by grazing intensity. Since the experimental years were much dryer than the long term average, the abiotic constraints may have overridden any grazing effect. The differences among the years were predominantly determined by the abiotic factors of temperature and precipitation. Most of the variations in species dynamics and coexistence between the C₄ and C₃ species were explained by seasonal weather conditions, i.e., temperature and precipitation regimes during the early season (March-June). The dominant C₃ species, Poa bulbosa, was highly competitive in March-June at low and high temperature and rainfall levels, respectively. In contrast, the most common C₄ species Cynodon dactylon benefited from high and low early season temperature and rainfall levels, respectively. However, biomass of P. bulbosa was positively correlated with temperature in March, when effective mean temperature ranges from 0 to 5°C and thus promotes vernalization and vegetative sprouting. Our results suggest that, over a six-year period, it is temporal variability in temperature and precipitation rather than grazing that determines vegetation dynamics and species distributions in grazed semi-steppe ecosystems. Our results also support that the variability in the dominant species biomass, rather than diversity, determine ecosystem functioning. This study provides fundamental knowledge on the complex interaction of climate, vegetation, and grazing.     

Path analysis of genotype × environment interactions in rainfed durum wheat

This study was investigated to analyze genotype × environment (GE) interactions for grain yield and its components and to investigate the mechanism by which the stability of grain yield is achieved in rainfed durum wheat. Twenty-four durum wheat genotypes (breeding lines, old, and new varieties) along with one old bread wheat cultivar were tested in 21 diversified rainfed environments during 2010–2013 cropping seasons. The data were analyzed by path analysis model which is composed of a main effect and four multiplicative effects. The flowering time (X1), maturity time (X2), plant height (X3), and 1000-kernel weight (X4) were assumed to be sequential characters for the development of grain yield productivity (Y) in rainfed durum wheat. A high relationship (p < .01) between observed and expected yields of genotypes in different environments confirmed the validity of the causal scheme adopted in the analysis. Comparison the estimates of components provided information on the degree of response of each genotype to the environmental stresses. The results indicated that higher grain yields are associated with higher kernel weight (v₄), which resulted from early flowering (v₁), and so more emphasis should be given to these traits for the improvement of yield potential in durum wheat under highland rainfed conditions of Iran. Positive correlation of stability variance (σ²) with v₄ component indicated that the kernel weight is the main contributor towards GE interaction for grain yield in rainfed durum wheat.     

Incorporation of AMMI stability value and grain yield in a single non-parametric index (GSI) in bread wheat

In order to determine stable bread wheat genotypes with high grain yield via a single parameter, field experiments were conducted with 20 genotypes for 4 consecutive years in two different conditions (irrigated and rainfed) in a completely randomized block design with three replications in each environment. Combined analysis of variance showed highly significant differences for the GE interaction indicating the possibility of selection for stable entries. The results of additive main effect and multiplicative interaction (AMMI) analysis revealed 10% of total variability was justified by the GE interaction which was 2.5 times more than that of genotypes. Ordination techniques displayed high differences for the interaction principal components (IPC1, IPC2 and IPC3), exhibiting that 83% of the GE sum of squares was justified by AMMI1, AMMI2 and AMMI3, i.e., 3.77 times more than that explained by the linear regression model displaying the relative efficiency of AMMI1 model in comparison with regression model. AMMI stability value (ASV) discriminated genotypes G6, G9, G14, G15, G17 and G18 as the stable entries. As stability per se is not a desirable selection criterion, because the most stable genotypes would not necessarily give the best yield performance, hence, simultaneous consideration of grain yield and ASV in a single non-parametric index entitled: Genotype Selection Index (GSI), discriminated G6 and G17 with general adaptability and high grain yield for rainfed and irrigated conditions which was in agreement with the results of biplot analysis.