Iranian Journal of Crop Sciences
Year:2010 | Volume:12 | Issue:3 (47)|Papers Count:13

To study the effect of planting pattern on yield, yield components, oil and protein contents in safflower cv. Sina in dryland condition, a field experiment was conducted at the Agricultural Research Field Station of Ilam, in the autumn of 2007-2008 cropping season. A split plot arrangement in randomized complete block design with three replications was employed. Three row spacing (30, 40 and 50 cm) were assigned to main plots and three plant spacing (10, 15 and 20 cm) were randomize in sub-plots. The main effect of row spacing on head.plant-1, grain.head-1, 1000 grain weight, head weight, days to flowering, days to maturity and protein content was significant. Mean comparison for row spacing showed that 30 cm row spacing had the highest head.plant-1 (12.1), 1000 grain weight (31.1g) and protein (17.1%). The effect of plant spacing on head.plant-1, 1000 grain weight, head weight, days to flowering, days to maturity and protein content was also significant. Mean comparison for plant spacing showed that the 10 cm plant spacing had the highest head.plant-1 (12.4), 1000 grain weight (30.5g) and protein content (16.9%). However, grain yield was affected by by neither row spacing nor by plant spacing , but the highest grain yield obtained from 30 cm row spacing (1124 kg.ha-1) and 10 cm plant spacing (1086 kg.ha-1). The highest oil content obtained from 40 cm row spacing (29.1%) and 20 cm plant spacing (29%). Results of the present experiment showed that the 30x10 cm planting pattern performed better in safflower cultivation.

Modifiying canopy structure to provide conditions in which the crop canopy could absorb better light has been known as an important strategy to increase crop yield. In this field study, the effects of planting pattern, plant density and nitrogen levels on grain yield, yield components and some agronomic characteristics of maize cv. SC704 were evaluated in 2008 cropping season. The field experiment was carried out at the experimental farm of faculty of agriculture Shiraz University, in split-split-plot arrangements using RCBD with three replications. Planting patterns (conventional single row=SR, parallel double row=PDR, and zigzag double row =ZDR) were randomized in sub-sub-plots, plant densities, (80000, 90000, 100000 and 112500 plants. ha-1) were randomized in sub- plots and nitrogen levels (90 and 180 kg. ha-1) were assigned to main plts. Interaction effect of planting patterns and density on grain yield, grains per ear and 1000 grain weight was significant. The highets grain yield (15550 kg. ha-1) was obtained from 100000 plants. ha-1 and ZDR planting pattern. Interaction effect of nitrogen levels × density, and nitrogen levels × planting patterns on grain yield, harvest index, grains per ear and 1000 grain weight were also significant. Therefore, the highest biological yield was obtained from application of 180 kg N. ha-1 at 100000 plants. ha-1 (27045 kg. ha-1). However, the highest harvest index was obtained from application of 180 kgN. ha-1 and ZDR planting pattern (61.38%). It seems that application of 180 kgN. ha-1 and ZDR planting pattern could improve the grain yield of maize cv. SC704.

To evaluate the effect of artificial defoliation intensity at different growth stages on the root yield and quality of sugar beet (Beta vulgaris L.) a field experiment was carried out at Miyandoab Agricultural Research and Natural Resources Field Station in 2007 growing season. Experimental treatments were arranged as factorial (4×5) in RCBD with three replications. Defoliation were practice at four growth stages (S) of sugar beet including: plant establishment to 10% ground cover (S1), from 10 up to 70% ground cover (S2), from the S2 to root maturity (S3), and from the S3 to harvest time (S4). Five levels of defoliation intensities (I) were: blade removal up to 25% (I1), 50% (I2), 75% (I3), 100% (I4) and no defoliation as check (I5). At final harvest, sugar beet roots were harvested and root yield, sugar content, white sugar content, white sugar yield and extraction coefficient of sugar were determined. Results showed that the main effect of growth stage was significant on quality traits of sugar beet such as sugar content, white sugar content and sugar extraction coefficient, however, its effect on agronomic traits such as root yield was not significant. However, different levels of defoliation affected both quality and quantitative traits of sugar beet. At the 100% defoliation level, root yield reduced by 36% as compared to no defoliation (47.49 t. ha-1). In the meantime the least root yield (23.90 t. ha-1) was recorded at S2 with 100% defoliation (S2I4). The interactions between defoliation intensity × growth stages were significant (P<0.01) for sugar content and white sugar content. At the 25% defoliation (I1) at final growth stage (S4), sugar content decreased by 4.65 units whic was 22% of no defoliation (sugar content of 21.50%). In conclusion, any defoliation during the growing season may increase sugar losses in the sugar factory.

To study the effect of different irrigation intervals on the yield and plant characteristics of potato (Solanum tuberosum L.), a field exoeriment was carried out in split plot arrangements using randomized complete block design with three replications at research field station, faculty of agricultural, the university of Urmia, in 2008 growing season. Experimental treatments were included irrigation intervals at four levels: 6 (I0), 10 (I1), 14 (I2 ) and 18 (I3) day assigned to main plots, and growth stages at two levels: 50% emergence to 50% flowering (GS1) and 50% flowering to physiological maturity (GS2) randomized in sub-plots. Results showed that tuber fresh yield, tuber dry yield, mean of tuber fresh weight. plant-1, stem diameter, plant height, tuber size and dry matter at 1%, and the number of stem and relative water content in 5% probability level were affected by different irrigation intervals. However, irrigation intervals had no significant effect on mean of tuber dry weight. plant-1, specific weight and cell membrane stability. Significant difference was also observed between the growth stages for stem diameter, plant height and cell membrane stability. Interaction effect between irrigation intervals x growth stages was not significant on any traits except for stem diameter and plant height. It was concluded that irrigation intervals had a significant effect on plant characteristics of potato, but growth stages had no effect on these traits.

Solid medium of poly ethylene glycol (PEG 6000) was used to induce various levels of water stress for evaluating the reaction of seedlings of 20 different genotypes of sugar beet under water stress conditions. Fifteen restorer lines (O-Types) are tolerant of drought and five genotypes (control) with three of them tolerant, one moderately-tolerant and one sensitive to drought as well as four drought stress levels of osmosis potentials: 0, -0.6, -0.7 and -0.8 MPa (from combination of 0, 15, 20 and 25% PEG, respectively). A factorial arrangements (4×20) in CRD with three replications was employed in the tissue culture environment. In each experimental units shoot and root length, shoot fresh weight and dry weight of shoots and roots in all seedlings were determined following growth of sugar beet genotypes in the solid media of PEG for 30 days. The ANOVA showed that the main effects of water stress, genotype and their interactions were significant (P<0.01) on shoot and root fresh weights. Effect of genotype was significant (P<0.01) for shoot and root lengths. There was significant interatction for shoot length (P<0.01) and root length (P<0.05). Results confirmed that there was high genetic variation among sugar beet genotypes under water stress conditions. Genotypes G16 and G18 among checks and genotypes G10, G4, G7 and G5 among O-types showed the least reduction in all traits as compared with to the other genotypes. It could be concluded that under water stress condition (up to 0.6 MPa in PEG medium), root length and root fresh weigth seems to be suitable traits in sugar beet seedlings genetic diversity assessment.

A population of 278 RILs (F8 Recombinant Inbred Lines) of bread wheat derived from a cross of Attila/Kauz (salt sensitive) and Karchia (salt tolerant) were evaluated in α-Lattice Design with two replications under two envirnemntal conditions (normal: water and soil salinity=2 dS. m-1 & salinity stress: water salinity=11-17 dS. m-1 and soil salinity=13 dS. m-1) in Yazd in 2008, to determine the effect of salinity on grain yield and other characteristics. Analysis of variance showed that there were significant differences among varieties for concerned characteristics, indicating the existence of genetic variation among RILs. Salinity reduced the mean of characteristics, particularly, grain yield and grain weight spike-1. The genotype x envirnemnet interactions was highly significant on grain yield and grain weight spike-1, spike weight and some other characteristics, indicating that RILs responed differently to salinity condition for these characteristics. In contrast the genotype x environment interaction on plant height, pedancle length, spikes lenght and grain no. spike-1 were not significant, indicating a lower differential response to salinity For these characteristics. Biomass and harvest index, had the highest correlation with grain yield in normal and salinity stress conditions.

Twenty advanced barley lines, and two checks (Sararood-1, and local variety) were evaluated under three moisture regimes, i. e. rainfed, one irrigation at sowing, and two irrigations at sowing and flowering time. Three experiments were performed in randomized complete block design with four replications, for three years (2002- 2005), at Sararood field station, Kermanshah, Iran. The barley genotypes were evaluated for drought stress tolerance by measuring different stress susceptibility/tolerance indices, using yield performances under rainfed and two irrigations conditions. Screening of tolerant genotypes for drought tolerance was carried out in two steps, first by selecting genotypes with highest sum for ranks of stress tolerance indices, and then eliminating of those with higher stress susceptibility indices. Grain yield stability analysis was also performed using Eberhart and Russel’s method. Considering grain yield under stress and non stress conditions, grain yield stability parameters, and values of stress tolerance/susceptibility indices, genotypes 11, 2, 9, 12, 13 along with the checks showed outstanding performances that could be used in barley breeding programs as well as furher tested in onfarm trials.

Forty two hybrids and their sevent parents were planted at the Research Field Station of Islamic Azad University of Firoozabad in 2006 cropping season- using a Randomized Complete Block Design (RCBD) with three replications. Days from germination to physiological maturity, days from silking to physiological maturity, plant height, ear height, ear length, 100-grain weight, grain depth, number of rows. ear-1, number of kernels. row-1 and grain yield were measured and recorded. ANOVA showed significant differences between genotypes as well as significant effect of general combining ability (GCA) and specific combining ability (SCA) for all measured traits. Effect of reciprocal crossing was also significant for 100-grain weight, grain depth, number of rows. ear-1, number of kernels. row-1 and grain yield that indicated the presence of cytoplasmic inheritance for these traits.Based on MSGCA/MSSCA ratio, additive gene effect was predominant in controlling days from germination to physiological maturity, ear length, number of rows. ear-1 and number of kernels. row-1 traits. The broadsense heritabilities ranged between 48% and 89% for days to physiological maturity and number of rows. ear-1, respectively. Narrowsense heritabilities were estimated between 10% and 49% for days from silking to physiological maturity, plant height and ear length. These results showed that non-additive genetic effects were predominant in controlling days from silking to physiological maturity, plant height, ear height, 100-grain weight, grain depth and grain yield. Considering hetrosis in comparison to the superior parents as well as general and specific combining abilities for parents and hybrids indicated that parents 1 and 4 had high potential for traits like ear length and number of kernels. row-1; parent 2 for grain yield; parent 3 for early maturity, increasing grain depth, number of rows. ear-1 and grain yield; parent 5 for 100-grain weight; parent 6 for 100-grain weight, number of rows. ear-1 and grain yield and parent 7 for 100-grain weight, grain depth and number of rows. ear-1.

Genetic diversity of 73 accessions of two barely species (H. vulgare L. and H. spontaneum L. ) was evaluated using 15 SSR pair primers. Patterns were scored by 0 (band abscence) and 1 (band presence). Dendrogeram was constructed using dice similarity coefficient and UPGMA algorithm by software NTYSYS 2.02. Principle coordinate analysis was also performed. The highest numbers of polymorphic alleles in H. vulgare L. accessions were observed in gene loci Bmac 0316 and Hvm40 with eight alleles in each. The lowest numbers of polymorphic alleles in H. vulgare L. accessions were observed in gene locus Hvm70 with two alleles. Moreover, the highest numbers of polymorphic alleles in H. spontaneum L. were observed in Hvm40 locus with 9 allels, while the lowest obtained in Hvm70 and HvmloH1A with two alleles, respectively. The highest PIC value in H. vulgare L.was 0.8 (gene loci Bmac0040) and the lowest 0.19 (gene loci Bmag0603). While, the highest and the lowest value of PIC in H. spontaneum L. ranged from 0.43-0.91. Cluster analysis using Dice similarity method and UPGMA algorithm, grouped all accessions in three main groups. Group one included populations from both of H. vulgare L. and H. spontaneum L. species collected from Iran, while groups two and three included accessions of H. spontaneum L. and H. vulgare L., respectively. Results showed that SSR markers can be apllied as reliable tool to evaluate genetic diversity between and within H. vulgare L. and H. spontaneum L. species. Loci HvmLoH1A and Ebmac0415 in H. spontaneum L. and loci Bmac0306 and Bamc0040 in H. vulgare L. can be used to estimate genetic diversity in these two barely species.

Cell cycle, which is the basic reference for cell division and growth, is precisely regulated. Control of cell cycle progression in animal and plants needs regulation of gene expression. In this study, by means of inducing synchronization of Arabidopsis suspension cells using aphidicolin, trend of expression changes in several genes involving in different stages and biochemical pathways of cell cycle was investigated. Application of highly sensitive detection method, qRT-PCR enabled us to precisely monitor the behavior of the genes in different stages of the cell cycle. Expression patterns of 69 core cell cycle–related genes and 81 transcription factors were compared, and their possible roles in the specific stages of the cell cycle were analysed. Among the genes showing differential expression during progression of the cell cycle, cyclin type A and B and CDK have been reported to play key roles. The expression patterns of most of cyclin type A and B genes appeared to be similar.A subset of the cyclins, CYCA3 showed maximum expression in S phase which is considered as the most important kinases involved in this phase. CDK genes showed important role in G1/S and G2/M transition stages.Many transcription factors belonging to different transcription factor families showed fluctuations in different time of progression of the cell cycle that play significant role in the precise control of the cell cycle processes.