Iranian Journal of Crop Sciences
Year:2007 | Volume:9 | Issue:2 (34)|Papers Count:7

Effective assessment of genotypes superiority is possible by identification of spatial variability and selection of appropriate methods of statistical analysis. In order to select suitable genotypes for advanced trials in dryland conditions, 100 safflower pure lines were evaluated using simple lattice by accounting for spatial variability. Results showed that, the lattice design with correlated errors along rows, the lattice design and the randomized complete block, design with first order auto-correlated errors along rows were the best models and most effective in accounting for spatial variability in grain yield, plant height and days to flowering, respectively. There was not any evidence for fixed trend in this experiment. Broad sense heritability estimates revealed a significant genetic potential for selection for all of the measured characters. Based on the selected models, the best linear unbiased estimates for all genotypes were calculated and the superior genotypes were selected regarding related standard errors. Since the criterion used was based on maximum information of the data, the interpretations drawn from the best model for each trait would give the most realistic assessment of the performance of genotypes. Hence, for breeding objectives, it is recommended that at first a best model be identified to describe the spatial variation in the data, followed by evaluation of the genotypes based on that model.

A simple mechanistic crop growth simulation model “WheaPot” was developed for simulating site-specific wheat yield potential. The model simulates critical phonological stages and dry matter production as a function of temperature and solar radiation. Crop aspects of the model including developmental stages, dry matter production and grain yield are modulated in sub-models. The model requires inputs of site mean monthly weather data (minimum and maximum temperatures inoC) and photosynthetically active radiation (PAR in MJ m-2), and plant characteristics such as sowing date, required growing degree days (GDD) for vegetative and reproductive phases, radiation use efficiency (RUE in g MJ-1), and harvest index (HI). The model was verified using different experiments, which were carried out in several locations in Khuzestan province in 2003-2004 and 2004-2005 growing seasons. Comparison of simulated and measured values under non-limiting conditions indicated satisfactory performance of the model in predicting anthesis and maturity dates, and a fair prediction of dry matter production and grain yield with root mean square error (RMSE), 3.5 d, 4 d, 0.65 t ha-1 and 1.69 t ha-1, respectively. The model proved as a useful tool for a rough estimation of wheat yield potential at regional level where there is no access to daily weather data.

To evaluate the effect of sorghum interference on soybean growth parameters and grain yield, a field study was conducted in experimental field of the Faculty of Agriculture, The University of Tabriz during 2002 and 2003. Treatments were arranged in a factorial experiment using a randomized complete block design with three replications with additive series method. The first factor consisted of soybean densities of 20, 30, 40, and 50 pants/m2 and the second factor included sorghum densities of 0, 4, 8, and 12 plants/m2. Results showed that the highest dry matter accumulation (DMA), crop growth rate (CGR) and grain yield (GY) of soybean were observed in pure stands of soybean. Among pure stands, the highest and the lowest DMA, CGR and GY were achieved in soybean densities of 50 and 20 plants/ m2, respectively. These parameters were decreased by increasing sorghum density. However, the loss rate was higher at 4 plants/m2 as compared to other sorghum densities. Therefore, it can be concluded that DMA, CGR and GY are decreased, due to increasing sorghum density; however, these parameters are slightly affected by soybean density.

In order to determine the best irrigation interval, nitrogen rate and nitrogen splitting on essence of German chamomile (Matricaria chamomilla L.), a field experiment was conducted in the Experimental Field of the Islamic Azad University of Tabriz, in 2006-2007 cropping season. The experiment was established as a randomized complete blocks design using a split plot factorial arrangement and three factors including irrigation intervals (I1=6; I2=12, I3=18 days) in main plots, and factorial combination of nitrogen (urea) rate (N1=50; N2=100, N3=150 kg ha-1) and nitrogen splitting (T1= 100% at planting time; T2= 50%: 50% at planting and stem elongation stages, T3= 25%: 50%: 25% at planting, stem elongation and early flowering stages, respectively) in subplots. Results revealed that application of 100 kg ha-1 and increasing irrigation intervals from 6 to 12 days had positive effect on flower number per plant. The highest dry flower yield (378.8 kg ha-1) belonged to I1N2. Application of nitrogen fertilizer at T2 increased dry flower yield up to 350.5 kg ha-1, in comparison with T1 and T3, respectively. Flower essence content was not affected by nitrogen fertilizer splitting; however, it was affected by two other factors. Essence yield ranged from 1.56 l ha-1 in I3N3 up to 3.63 l ha-1 in I2N2. Nitrogen fertilizer application at T1 and T3, both caused a significant reduction on flower essence.

ABC-Transporter proteins superfamily is found in all alive organisms as connection bridge in cellular membranes. These proteins are responsible for transportation of variant substrates such as metabolites that involved in plant defense mechanisms. In this study SNPs and CAPS markers were used for mapping of an ABC-Transporter which is specific for compatible and incompatible interaction against R. secalis fungus. A 2.2kb fragment derived from PCR product with specific primers for mentioned gene was sequenced in 10 barley parents. Among observed SNPs, one SNP showed different restriction enzymes sites in Chebec and Harrington parents and converted to CAPS marker. Results mapping revealed position of the gene on long arm of barley chromosome 3. Also, a homology evaluation for this region of chromosome was in accordance with previous studies about high synteny for barley chromosome 3 with rice chromosome 1.

Effect of four irrigation regimes (irrigation after 100,130,160 and 190 mm evaporation from class A pan) on yield and its components of four grain sorghum cultivars namely Local Ardestan , Payam, Sepedeh and Kimya was studied, using split plot design with four replications, in Research Field Station of Faculty Agriculture, Isfahan Technology University. Analysis of variance and mean comparison between treatments showed that yield and its components had negative response to water stress condition, and with increasing irrigation intervals from I1 to I4 these values decreased significantly. Therefore, grain yield reduced 9% in I2, 27% in I3 and 51% in I4 in comparison to I1. There was considerable variation among the cultivars in grain yield and its components. Results also showed maximum plant height and biological and grain yield in local Ardestan, maximum grain per panicle in Sepideh and latest maturity to Kimya cultivars. Irrigation× cultivar had significant effect on grain yield and its components of sorghum cultivars. Local Ardestan cultivar had the least yield reduction under these conditions.

With more than 23 species of Medicago, Iran is one of the origins and centers of diversity of this genus. Due to close similarity in sexual organs and pod-characteristics, taxonomical classification of these species based on morphological characteristics is difficult. Scanning Electron Microscopy (SEM) was used to study the major characteristics of pollen grain among Iranian Medicago species. Pollen grains were mostly tricolpate, but quadricolpate or hexacolpate pollen grains were also observed in one species. The equatorial view was elliptic to rectangular or spherical shapes and the polar view was obtuse-triangular, truncate-triangular or square tips. Majority of species showed reticulate (perforate, faveolate, regulate and, scrobiculate) and verrucate exine surface. M. rigiduloides with quadric or hexic colpate pollen grain was barely distinguishable from M. rigidula with tricolpate pollen exine surface. On the other hand, M. tornata with its spherical pollen and verrucate exin surface was obviously different from M. polymorpha with rectangular pollen grain and reticulate exine surface. This is the first report of M. rigiduloides and M. tornata from Iran.