Leaf area estimation is an important measurement for comparing plant growth in field and pot expe... more Leaf area estimation is an important measurement for comparing plant growth in field and pot experiments. In this study, determination of the leaf area (LA, cm 2 ) in soybean [Glycine max (L.) Merr] involves measurements of leaf parameters such as maximum terminal leaflet length (L, cm), width (W, cm), product of length and width (LW), green leaf dry matter (GLDM) and the total number of green leaflets per plant (TNLP) as independent variables. A two-year study was carried out during 2009 (three cultivars) and 2010 (four cultivars) under field conditions to build a model for estimation of LA across soybean cultivars. Regression analysis of LA vs. L and W revealed several functions that could be used to estimate the area of individual leaflet (LE), trifoliate (T) and total leaf area (TLA). Results showed that the LW-based models were better (highest R 2 and smallest RMSE) than models based on L or W and models that used GLDM and TNLP as independent variables. The proposed linear models are: LE = 0.754 + 0.655 LW, (R 2 = 0.98), T = -4.869 + 1.923 LW, (R 2 = 0.97), and TLA = 6.876 + 1.813 ΣLW (summed product of L and W terminal leaflets per plant), (R 2 = 0.99). The validation of the models based on LW and developed on cv. DPX showed that the correlation between calculated and measured LA was strong. Therefore, the proposed models can estimate accurately and massively the LA in soybeans without the use of expensive instrumentation.
Rapid test for detecting haloxyfop-R methyl ester resistance in winter wild oat (Avena ludoviciana durieu)
Background and ObjectivesDetection of resistance to an herbicide in a putatively resistant access... more Background and ObjectivesDetection of resistance to an herbicide in a putatively resistant accession requires a series of experiments which are capable of illustrating the response of the accession to various herbicide doses. Whole plant bioassay in pots usually takes approx. 2 months to obtain the results, thus, rapid tests were developed to accelerate the process. Although determination of discriminating concentration as well as conduction of rapid test for some ACCase inhibitors has been performed by various researchers, no reports are available in this regard for haloxyfop-R methyl ester herbicide in winter wild oat. Thus, the following study was conducted with the objective of rapid detection of resistance to the mentioned herbicide in this weed using the rapid test.Materials and MethodsThe experiments were conducted using the seeds of 7 putatively resistant winter wild oat accessions and a susceptible biotype gathered from canola farms of Kalaleh township located in Golestan province in 2015. Rapid test in petri dishes was conducted as a completely randomized design with three replications, with each petri dish as one replicate. To determine the discriminating concentration, various concentrations of haloxyfop-R methyl ester was applied on the susceptible accession and then, all putative accessions were screened using this concentrations. The biotypes of the studied weed were exposed to various doses of the herbicide in the petri dish bioassay to determine the resistance factor. Also, a completely randomized design experiment with three replications was conducted for screening of putative accessions in the greenhouse. Accessions which maintained their survival and dry weight respectively 50 and 80 percent compared to the unsprayed control were selected. A whole plant dose-response bioassay was also done separately for each biotype. Resultsdiscriminating concentration of haloxyfop-R methyl ester for winter wild oat was obtained 0.106 mg ai. L-1. According to the results 5 out of 7 accessions were detected as resistant and underwent the concentration- response assay in petri dishes. Resistant factors of the biotypes in the rapid test ranged from 2783.054 to 3421.414. However, no significant difference was observed among the biotypes. According to the of the greenhouse, 5 accessions were detected as resistant with resistance factors of 14.19 to 18.54, with no significant difference among the biotypes. There was a positive and significant correlation between the results obtained from the rapid test with the greenhouse assay.DiscussionPutative winter wild oat accessions collected from the region may be screened using this concentration (0.106 mg ai. L-1) and resistant biotypes may be detected more rapidly compared to greenhouse assays. Also, the results of the rapid test are in accordance with those of the whole plant assay in pots. Due to the swift development of herbicide resistance issue, rapid detection of resistance is essential. Thus, using methods such as rapid test may be very feasible.
Determination of Competitive Ability of Canola Cultivars Against Wild Mustard (sinapis Arvensis) Using Some Empirical Models in, Golestan Province, Iran
Journal of Agricultural Science and Technology, Dec 1, 2009
The modeling of germination and seedling emergence is required for the construction of a simulati... more The modeling of germination and seedling emergence is required for the construction of a simulation model of three species of millet (panicum miliaceum, pennisetum galucum and setaria italica). This study provides the necessary temperature parameters to model these processes. For this purpose, different non-linear regression models including flat, logistic, quadratic, sigmoidal, dent-like, segmented, beta and curvilinear were used. Root Mean Square of Errors, coefficient of determination and regression coefficients of predicted values versus observed were used to find the appropriate model. Investigating regression coefficients indicated that dent-like model has the least RMSE and a coefficient (RMSE=0.000009, a=0.0006) and the biggest R 2 and b coefficient (R 2 =0.96, b=0.98) in common millet. These coefficients were (RMSE=0.01, a=0.005) and (R 2 =0.94, b=0.97), and (RMSE=0.004, a=0.05) and (R 2 =0.99, b=0.99), for beta in foxtail and pearl millet, respectively. According to these coefficients, dent-like, was chosen as the best model to describe the response of common millet germination to temperature (T b =7℃ and T c =49.50℃). Also beta, was chosen for foxtail millet (T b =7℃, T c =49.50℃). Beta, was chosen as the best model for pearl millet (T b =6.5 ℃ and T c =4 ℃ ). These parameters can be used in millet simulation models to predict sowing to emergence duration based on a thermal time concept. Also, required biological days from sowing to emergence using these models varied from 3.57, 4.29 and 5.54, for common millet, foxtail millet and pearl millet, respectively.
Determination of the Most Important Yield Component of Wheat in Different Sowing Dates
In order to determine the most important yield component of two wheat (Triticum aestivum) cultiva... more In order to determine the most important yield component of two wheat (Triticum aestivum) cultivars (Zagros and Koohdasht), a RCBD experiment was conducted with five sowing dates (14 December, 20 Januery, 18February, 20 March, 16 April) with three replications. In this ...
Determination of Temperature-Related Parameters and Response Ranges of Almolookhiyeh (Corchorus Olitorius L.) Seeds and Seedlings Using Nonlinear Regression
The rice yield gap estimation using integrated system approaches: a case study—Guilan province, Iran
International Journal of Environmental Science and Technology, Mar 31, 2022
Today, food security is a major human concern. Therefore, research on crop yield and yield gap ha... more Today, food security is a major human concern. Therefore, research on crop yield and yield gap has been seriously increasing in recent years. For this purpose, the yield gap of rice fields in Guilan province was investigated using the ORYZA2000 model and integrated GIS-RS approaches. First, to estimate the coefficients of the ORYZA2000 model, an experimental survey was performed in the Rice Research Institute of Iran in the 2016 and 2017 years. At first, with the help of the model, the potential yield of rice in Guilan province was predicted. SDVIs (Satellite imagery-derived vegetation indices) were extracted from Sentinel-2 and Landsat 8 satellite images. SDVIs were evaluated to select the most proper one for generating the actual yield raster. Finally, the map of the yield gap was prepared from the differences between potential yield and actual yield rasters. The result showed that the NRMSE in the simulation of grain yield and aboveground biomass was less than 8%. The yield gap in rice cultivated farms of Guilan province during the two years of the experiment was estimated to be between 37 and 3090 kg ha−1. The results of this study can provide good basic information for optimizing rice yield.
Advances in Plants and Agriculture Research, May 28, 2018
and it is not considered comprehensively for the understanding of relations and phenomena. Based ... more and it is not considered comprehensively for the understanding of relations and phenomena. Based on this idea, soil is not considered as a living and dynamic entity, which contains a collection of living organisms and biological, physical and chemical interactions, but rather as a mere non-living physical environment, which humans are allowed to manipulate its structure and function by means of using machinery, fertilizers, chemical pesticides and other inputs. In this view, that reflects the basic principles of agricultural economics, natural resources have always been valued in the right way as other sources such as inputs and labor, and in this way, the values and functions of life and the ecology of nature is far from over. The result of such a view was the human invasion of natural resources and the reduction of ecological reserves.
Rice (Oryza sativa L.) is an important primary crop in Iran. In this study, energy use pattern fo... more Rice (Oryza sativa L.) is an important primary crop in Iran. In this study, energy use pattern for rice production was analyzed and compared in different geographical regions, Golestan, Mazandaran and Guilan, northern provinces of Iran. There is a significant difference among the three provinces in respect to input energy and agronomical managements such as crop rotation, transplanting date and land preparation. Data were collected from 50 farmers using a face to face questionnaire-based survey. The data collected belonged to the production period of 2012e2013 with the following results obtained. The energy use efficiency varied from 1.39 for Golestan to 1.67 for Guilan provinces. The research results revealed the main difference between energy consumption in three provinces comes from diesel fuel, chemical fertilizers and electricity. The net energy for paddy production was approximately higher in Guilan (36,927.58 MJ ha À1 ) than other provinces. Also, the values of energy productivity (kg MJ À1 ) for Golestan, Mazandaran and Guilan provinces were found to be 0.064, 0.059 and 0.070, respectively. On average 84.70% of total energy input used in rice production was non-renewable, while the contribution of renewable energy was 15.30. The results showed that the total energy input for rice production in Golestan province was 64,158.78 MJ ha À1 which was higher than other provinces, due to high energy consumption in diesel fuel style (46.44%).
Field screening of canola (Brassica napus) cultivars against wild mustard (Sinapis arvensis) using competition indices and some empirical yield loss models in Golestan Province, Iran
Crop Protection, Jul 1, 2009
... leveller. Plots were 8 m long with 10 rows spaced 24 cm apart. All the cultivars were planted... more ... leveller. Plots were 8 m long with 10 rows spaced 24 cm apart. All the cultivars were planted at their optimum density (80 plants m −2 ), as proposed by the Iran Seed and Plant Improvement Institute (Omidi et al., 2005). They ...
Consecutive application of herbicides has led to the evolution of herbicide-resistant weeds. This... more Consecutive application of herbicides has led to the evolution of herbicide-resistant weeds. This resistance is often associated with a fitness cost. Hence, a completely randomized design experiment with three replications was conducted to evaluate the fitness cost of haloxyfop-R methyl ester resistant winter wild oat biotypes (Avena ludoviciana Durieu) possessing Ile-2041-Asn mutation compared to susceptible ones. The pre-germinated F2 generation winter wild oat biotypes were sown in 0.2 m 2 pots containing 50 cm of silty-loam soil outdoors and their growth parameters including tiller number, plant height, leaves per plant, leaf area per plant, chlorophyll content index, leaf dry weight, and plant dry weight were measured 30, 70, 100, 115 and 130 days after planting. Leaf area index, leaf area ratio, specific leaf area, relative growth rate, net assimilation rate, and crop growth rate were also calculated. Seed production, 1000 kernel weight, and flag leaf area were measured at the end of the growth period. According to the results, no fitness cost was observed between susceptible and resistant biotypes, indicating that susceptible biotypes may not overcome resistant ones in the field. Although imposing a new selective pressure via application of an herbicide possessing a different mode of action may control both susceptible and resistant biotypes, herbicide rotation must be adapted to impede the evolution of further resistance. Also, the same non-chemical weed management methods such as careful selection of sowing date can be implemented to ameliorate adverse effects of this weed on crop production.
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