farnaz goodarzi

In this study, optimum level of nitrogen fertilizer and plant spacing on the row were investigated in spinach cv.”Harrier” based on the aims of four scenarios: economic, health of food, marketable and optimum production, using statistical response surface methodology. The independent variables including plant spacing on the row (7, 11 and 15 cm) and nitrogen fertilizer (0, 200 and 400 kg urea ha-1), were evaluated using central composite design at Research Field of University of Tehran. Leaf fresh weight, biomass, leaf area index, nitrogen use efficiency, nitrate concentration and total chlorophyll traits were considered as dependent variables. The fitting of data to second order polynomial equation and optimization of responses was performed using Mnitab16 software. Increasing of plant spacing on the row had alone a significant effect on total chlorophyll traits. High levels of nitrogen fertilizer had an increasing effect on dependent variables, except nitrogen use efficiency. The optimum combination of variables and desirability function for economic, environmental, marketable and optimal production limit scenarios were at plant spacing on the row of 7, 7.48, 7.24 and 7 cm, nitrogen fertilizer of 189.9, 60.6, 189.9 and 149.5 kg ha-1, and 0.97, 0.77, 0.9 and 0.82, respectively. Based on desirability function results, the model possesses a high power to simulate optimum level of independent variables at economic scenario than the others.

The Identification of the factors affecting the yield and edible quality of spinach (Spinach oleracea L.) and their interaction with the environmental conditions are the most important issues in crop production management. In this experiment, the effect of three levels of plant density (71, 45 and 33 plant m-2), six levels of nitrogen fertilizer (100, 200, 250, 300, 350 and 400 kg urea ha-1) and control on yield, growth indices and quality of spinach was evaluated in the field condition. These experiments were carried in 2014-15 and 2015-16, in a randomized complete block design with three replicates. The results showed that interaction effects of nitrogen fertilizer and plant density and year only had Significant effcet on nitrate content (p < 0.001). Nitrogen fertilizer increased biomass, yield, growth parameters like leaf area index, crop growth rate, and qualitative parameters like nitrate content, potassium percentage, chlorophyll a,b and total traits while had not significant effect on net assimilation rate and relative growth rate. Interaction effects of plant density and year had a significant effect on all traits except potassium percentage (p < 0.001). The increase in plant density led to increase in the biomass, leaf area index and nitrate content but chlorophyll content was significantly decreased. It is suggested that in autumn cropping in Karaj region, and under high light and temperature conditions, 71 plants m-2 and 250kg urea ha-1 could be better to estimate the aims of economic profitability for highest yield and maintaining a healthy level of nitrate in the plant tissue.

Castor (Ricinus communis L.) is one of the most ancient medicinal oil crops in the world. It has been vastly distributed in different parts of Iran. Association analysis based on 16 combinations of ISSR primers was applied in order to identify ISSR markers associated with genes controlling 26 morphological traits in 12 populations of castor. The genotypes were evaluated for morphological traits in randomized complete block design with three replications in experimental field of Agricultural Research Center of West-Azerbaijan during 2012. Locus UBC-859 was the most effective marker to assessment the diversity in populations of castor. Based on 116 loci produced by ISSR primers, the studied genotypes divided into 6 subpopulations. Using mixed linear model (MLM), 26 loci were identified to be significantly associated with 17 morphological traits. R2 values ranged from 12.4% (UBC857-5) to 28.1% (UBC844-2). Most of the identified markers were associated specifically with one trait. UBC812-8 was associated with 8 traits. Common markers between some of the studied traits can be due to linkage or pleiotropic effects. The common markers lead to increase the efficiency of marker-assisted selection in plant breeding programs via simultaneously selection for several traits.

Castor (Ricinus communis L.) is one of the most ancient medicinal oil crops in the world. It has been vastly distributed in different parts of Iran. In the present study, the inter simple sequence repeat (ISSR) markers were used to evaluate the molecular genetic diversity among and within 12 castor accessions collected from 7 regions of Iran. Totally, 16 ISSR primers amplified 166 loci, of which 116 loci (69.89 %) were polymorph, indicating high genetic variability in castor germplasm. An accession-specific ISSR band was detected in ‘80-29’accession. Genetic distance among accessions ranged from 0.2 to 0.056. Analysis of molecular variance revealed a higher level of genetic variation within (80%) than between (20%) accessions. A model-based Bayesian approach subdivided 60 genotypes from 12 accessions into 6 subgroups. UPGMA dendrogram based on Nei’s genetic distance classified 12 accessions into 4 groups. The result indicates that there was no association between geographical origin and ISSR patterns. The results suggest that ISSR technique is a useful tool for studying genetic diversity in castor germplasm.