Showing 1096 results for Ro
M. Falahati-Anbaran, A. A. Habashi, M. Esfahany, S. A. Mohammadi, B. Ghareyazie,
Volume 10, Issue 3 (10-2006)
Abstract
Annual medics are used for hey production, soil protection, biological fixation of N2 and green manure. In the present study, the inter and intra specific genetic diversity and relatedness of 4 diploid and two tetraploid (M. rugosa and M. scutellata) annual medics were evaluated using microsatellite markers. PCR analysis was performed on genomic DNA from individual plant and PCR products were detected using standard polyacrylamide sequencing gel. Totally twenty five polymorphic alleles were observed in the studied species. Average intra-specific genetic diversity ranged from zero (0.0) in both M. rugosa and M. scutellata to 0.114 in M. minima species, and the level of genetic diversity was similar in both M. orbicularis and M. truncatula species. Analysis of molecular variance (AMOVA) was used to partition the overall genetic diversity into within and among species, and between diploids and tetraploids. The results revealed significant (P<0.05) inter and intra-specific genetic variation. Pairwise comparisons based on Fst indicated significant differences among all of the species. Clustering analysis using UPGMA algorithm based on coancestary coefficient revealed a clear genetic relationship among species. The hypothesis on a common origin of two tetraploid species was supported by UPGMA clustering and phylogenetic analysis. The high level of Genetic diversity in spiny pod species respect to spineless pod species suggested the high importance of species with spiny pods in annual medics evolution. The findings support the usefulness of microsatellite markers for assessing inter and intra specific genetic diversity, differentiation and genetic relationships.
H. R. Bagheri, G. Saeidi, P. Ehsanzadeh,
Volume 10, Issue 3 (10-2006)
Abstract
Safflower (Carthamus tinctorius L.) is an oilseed crop and can have a considerable contribution to vegetable oil production in the country, since it has a high adaptability to different environmental conditions. This crop is grown in summer time as a second crop in Isfahan province. Therefore, this study was carried out to investigate the agronomic characteristics of the safflower breeding lines which were isolated from local populations of Iran in early spring and summer planting dates. Seven genotypes were evaluated at two planting dates, early spring (16 March) and summer (21 June), using a randomized complete block design (RCBD) with 4 replications at the research farm of Isfahan University of Technology. The results showed that the number of days to emergence, days to flowering and maturity and plant height decreased considerably in the summer planting date. However, the harvest index, seed yield per plant and seed yield per plot and oil yield increased in this planting date. Yield components were not significantly different in the two planting dates, except that 100-seed weight was significantly and considerably more in the second planting date. The average seed yield of genotypes was 2498 and 2845 kg/ha in spring and summer planting dates, respectively. In the first planting date, seed yield varied from 1876 Kg/ha, (for Kouseh genotype as check variety) to 2908 Kg/ha for E2428 line (selected from Isfshan population). In the second planting date, seed yield had a variation of 2124 to 3186 Kg/ha for the genotypes of S3110 (selected line from Khorasan population) and C111 (selected from Kouseh population), respectively. In the second planting date the check variety (Kouseh population) had a seed yield of 2965 Kg/ha. In both first and second planting dates, genotypes of E2428 and C116 (selected line from Kouseh population) had the maximum oil content in the seed, (33.9% and 32.3%د respectively). Genotype by planting date interaction was significant for seed yield and oil yield, since late planting date reduced seed yield in genotypes of S3110 and E2428, but it increased these traits in other genotypes.
M. R. Jazayeri, A. M. Rezai,
Volume 10, Issue 3 (10-2006)
Abstract
This study was conducted at the Research Farm of Isfahan University of Technology in 2003 to evaluate drought tolerance potential of 20 oat (Avena sativa L.) genotypes including 14 cultivars released in Canada, two cultivars released in the United States of America and Switzerland and four Turkish breeding lines. A randomized complete block design with three replications was used in each irrigation treatment (i.e., irrigation after 70±3 and 130±3 mm evaporation from class A pan). Results of analysis of variance revealed significant differences among cultivars for all studied traits in both irrigation treatments, with the exception of plant height at heading stage and biological yield in stress condition. Stress condition significantly reduced all the traits. Also, the interaction of genotypes by irrigation treatments was significant for days to heading, grain and biological yields and 1000-grain weight. To evaluate drought tolerance of the studied cultivars, Rosielle and Hamblin tolerance index, mean productivity (MP), Fischer and Maurer stress susceptibility index and Fernandez geometric mean productivity and stress tolerance index were calculated based on yield data in stress and non- stress conditions. According to the obtained results, stress tolerance index seems to be the most effective index to identify tolerant genotypes. Rank correlations of stress tolerance index and grain yields in stress and non-stress conditions were 0.93 and 0.78, respectively. Based on this index, Boyer and Paisley were found to be the most tolerant cultivars.
Kh. Abolhasani, G. Saeidi,
Volume 10, Issue 3 (10-2006)
Abstract
This experiment was conducted to evaluate drought tolerance of selected lines from local populations of safflower (Carthamus tinctorius L.) at the Research Farm of Isfahan University of Technology in 2002. In this study, the 12 selected safflower lines from different local populations along with two exotic cultivars and a local population were evaluated at two different irrigation regimes, using a randomized complete block design with three replications. The first and second irrigation regimes were based upon the depletion of 50% and 85% of soil moisture content, respectively. The results showed that there were significant differences (p<0.01) among the genotypes for seed yield in both irrigation regimes. Also, the interaction between genotypes and irrigation regimes was significant (p<0.05). Based upon the genotype by environmental interaction analysis (method of Sneller and Dombek), the genotype H27 had the highest tolerance to drought stress, and its seed yield in the first and second irrigation regimes was 3353 and 3072 kg/ha, respectively. The growing variety in Isfahan province (Koseh population) was the most sensitive genotype to the drought stress and had a seed yield of 3525 and 2394 kg/ha in the above irrigation regimes, respectively. The assessment of different water stress indices (SSI, STI, TOL, GMP and MP) revealed that STI seems to be the most suitable index for recognizing the more tolerant genotypes to drought conditions and based on this index, E2428 was the most tolerant genotype, and the exotic cultivar of Ac-Sunset (from Canada) was the most sensitive one. The seed yield for genotype E2428 was 4174 and 3458 kg/ha, and for the genotype Ac-Sunset was 2004 and 1438 kg/ha in the first and second irrigation regimes, respectively.
G. Saeidi, A. Khandan,
Volume 10, Issue 3 (10-2006)
Abstract
The precision of evaluation for agronomic traits is very important in the field experiments to determine the genetic potential of genotypes or effect of treatments. The precision of the experiment mainly depends on the number of replications. The objective of this study was to investigate the effect of number of replications on the precision of genotype evaluation, estimation of variance components and on the heritability for agronomic traits in flax (Linum usitatissimum L.). In this study, nine genotypes of flax were evaluated for different traits, using a randomized complete block design with 8 replications. The results showed that the reduction of error variance due to increasing the number of replications mainly depended upon the type of the trait. For evaluation and estimation of heritability for number of seedlings /m2 and plant height, 3 and 2 replications were suitable, respectively. The results also showed that using more than 2 replications had no considerable effect on the prescision of evaluation, nor on the increase of heritability for days to maturity. Based upon the results, for evaluation of the number of capsules per plant, 3 or 4, and for seeds per capsules, 4 replications can be suggested. For seed yield that is the most important economic trait in flax, a relatively constant estimated mean and broad-sense heritability were obtained with 4 to 8 replicationshowever, using 2 or 3 replications over-estimated the mean of the triat (approximately 11%) and under-estimated the broad-sense heritability about 27% and 10%, respectively. With 2 replications, the estimated mean and broad-sense heritability for seed yield were 2017.6 kg/ha and 72.1%, respectively. Gain from selection for seed yield based on evaluation of genotypes with 2, 3 and 8 replications was estimated as 787, 796 and 798 kg/ha, respectively. Therefore, it seems that 2 replications can also be used for seed yield evaluation of genotypes in breeding programs of flax.
M. Moradi Shahrbabak, M. Sadeghi, S. R. Miraei Ashtiani, M. B. Sayadnejad,
Volume 10, Issue 3 (10-2006)
Abstract
This research was carried out to investigate the heterogeneity of milk yield variance components in different production levels of holstein cattles. The first lactation milk yield records of 95945 Holstein cattles, which had calved in 651 herds through years 1991 to 2000, were used in this research. Data was collected by the Animal Breeding Center of Iran and adjusted for two-time milking per day. Records were classified into three classes: low (less than 5275 kg), average (5275-6874 kg), and high (more than 6874 kg) based on the level of production. Variance components and genetic parameters were estimated using single and three-trait animal models for each class and three classes with Derivative Free Restricted Maximum Likelihood methods (DF-REML). Bartlett test showed significant differences for variance components between classes. Milk yield heritability was estimated as 0.205, 0.276, and 0.196 for low, average, and high class, respectively, in both single and three-trait analysis. The gentic correlation coefficient between classes ranged from 0.80 to 0.85, Phenotypic correlation coefficients between classes were low and ranged from 0.17 to 0.19. The highest rank correlation coefficient between estimated breeding value by single and three-trait model was obtained in average class. The average changes in the rank of common animals in the top 1% of cows were greather than the top 5% of bulls. Adjustment for heterogeneity of variance components suggested selecting more top cows from herds with high level of production.
N. Alizadeh, A. Babai-Ahary, Y. Assadi, M. Valizadeh, B. Passebaneslam,
Volume 10, Issue 3 (10-2006)
Abstract
Rape seed (Brassica napus L.) containing more than 40 per cent oil is one of the best oilseeds for cultivation in Iran. Sclerotinia stem rot is one of the important diseases of the rape seed, the causal agent being Sclerotinia sclerotiorum. The aim of our study was to assess the effect of the disease on the quantity and quality of the extracted oil and remaining foodstuff in a field experiment. In this research three cultivars including Okapi, SLM046 and Talayeh were examined under field conditions using a factorial design (cultivars and inoculations were two factors under study). The cultivars were inoculated with SK4 isolate of S. sclerotiorum. The inoculation was done on the plant stems at 30 cm height above the soil using Lewartosca method during mid flowering stage. One thousand- seed weight and glucosinolate, erucic and oleic fatty acids contents of the seeds were determind after the harvest. The results indicated that the infected plants in comparision with the controls had a lower 1000- seed weight and oleic acid content and a higher glucosinolates and erucic acid contents. There were significant differences among the genotypes in respect to all the studied traits except 1000- seed weight. Inverse correlation was observed between 1000- seed weight and erucic acid content or oil glucosinolates contents. It was concluded that the disease can reduce quantity and quality of seed oil and other nutrient contents.
J. Shakarami, E. Bazgir, M. Feizian,
Volume 10, Issue 3 (10-2006)
Abstract
To search for reproducible and environment-friendly antifungal agents, essential oils of five plant species including Myrtus communis, Mentha aquatica, Vitex agnus-castus, Thymus daenensis and Artemisia aucheri were studied for their inhibition effects on the mycelial growth of plant pathogenic fungi including Fusarium oxysporum, Pythium ultimum, Rhizoctonia solani and Gaeumannomyces graminis. The experiment was conducted using a completely randomized design of factorial experiment including three essential oil concentrations and three replications at 25±2 ºC on PDA. Results revealed that R. solani with 48.83 and P.ultimum with 89.62% mean of mycelial growth inhibition were the most resistant and the most susceptible fungi to the essential oils, respectively. The essential oil of M. aquatica and T. daenensis with 93.70 and 92.74% mean of mycelial growth inhibition showed the most inhibition effect and V. agnus-castus with 33.88% was the least mycelial growth inhibitor. The essential oil of M. aquatica and T. daenensis at 20 µl/petri plate (9 cm. in diameter) completely inhibited the mycelial growth of the tested fungi. Considering the high antifungal effect, and low human and environmental hazard of essential oils, it seems that the essential oils may be used for the control of plant pathogenic fungi, or at least they may be adopted as a model for the synthesis of new antifungal agents.
M. Arab-Abousaadi, E. Rowghani, B. Hassanzadeh,
Volume 10, Issue 3 (10-2006)
Abstract
The effects of different levels of metabolizable energy and energy to protein ratios on the performance of Fars native laying hens were examined during the second laying phase. In a feeding trial, 216 Fars native hens 42 weeks old were randomly allotted to 9 experimental diets using 6 replicated groups of 4 birds per cage. The diets were formulated with 3 levels of ME (2700, 2900 and 3100 kcal/kg diet). At each level of energy, 3 energy to protein ratios (195, 215 and 239) were considered. The diets were fed ad libitum for a period of 20 weeks (42-62 weeks). The results indicated that there were no significant differences in egg production, egg weight, body weight gain and livability at the end of the experiment (65 week of age) (P>0.05). Daily feed intake was significantly lowered in hens fed the first (ME=3100 Kcal/kg, CP=15.87), second (ME=3100 Kcal/kg, CP=14.43), third ration (ME=3100 Kcal/kg, CP=12.99) and fifth (ME=2900k Kcal/kg, CP=13.5%) as compared with the seventh ration (ME=2700 Kcal/kg, CP=13.82). Feed intake and feed conversion ratios (FCR) significantly decreased as the dietary energy level increased (P<0.05). Feed consumption at the highest energy level was significantly lower than that at the lowest energy concentration. FCR was influenced by dietary energy level. Hens on the diet with 3100 Kcal ME /kg had lower FCR compared to 2700 Kcal ME/kg. The feed cost per 1 Kg egg production increased significantly with the elevation of dietary energy and protein levels (P<0.05).The results showed that a diet containing 11.31% CP and 2700 Kcal ME/kg adequately satisfied the maintenance and production requirements of Fars native hens during the second phase of production. Also, this ration was more economical.
Kh. Jalili, S. H. R. Sadeghi, D. Nikkami,
Volume 10, Issue 4 (1-2007)
Abstract
Improper management of watershed land utilization has many ill effects on the available resources. Land use optimization is one of the proper strategies to achieve sustainable development and to reduce resource dissipation. Focusing on Brimvand watershed in Kermanshah province which comprises an area of 9572 ha, the present study was conducted to find out the most suitable land allocation to different land uses viz. garden, irrigated farming, dry farming and rangeland to achieve soil erosion minimization and benefit maximization. The soil erosion, net benefit and standard land capability maps were supposed as the inputs of the objective functions and to defined constraints. The multi-objective linear problem was then solved using simplex method with the help of ADBASE software package and ultimately the optimal solution was gained. Additionally, the results of the study revealed that the amount of soil erosion could reduce by 7.78% whereas the benefit increases at the rate of 118.62%, in case of implementation of optimal solution. The above mentioned optimization led to dry farming decrease and garden increase over that area. The results of sensitivity analysis also showed that objective functions were strongly susceptible to the variation of maximum constraint of irrigated farming and garden areas.
A. Hassanoghli, A. Liaghat, M. Mirabzadeh,
Volume 10, Issue 4 (1-2007)
Abstract
Increased chemical compounds in soil are the most important results of irrigation with domestic wastewater and treated effluents which contain some nutrients such as phosphorous (P). This process could increase the soil fertility, leading to the decrease of chemical nutrient consumption and consequently the cost of agricultural production. A research project was carried out in Tehran region for two years in order to investigate the capabilities of soil and plant in absorption and storage of wastewater contaminants, namely, phosphorous, and also the transmission of them to drain depth as a result of irrigation practice. To do the research, a series of lysimeters based on a statistical factorial experiment in the form of randomized complete design (3x3x3) were used. Raw and treated domestic wastewater, obtained from Ekbatan Housing Complex, and well water (control) were used to irrigate raw edible vegetables including parsley, carrot and tomato. The results showed that the amount of phosphorous leaching through soil to drain depth was between 0.90% and 3.56%, and between 1.03% and 4.15% of the phosphorous concentration in raw wastewater and treated one entered into the soil, respectively. Also, mass balance analyses showed the average phosphorous reduction ranged from 97.2% to 99.9% of the phosphorous entered with wastewater. During two years of study, the maximum concentration of PO4 measured in drained water was about 0.21 mg/L obtained from lysimeters irrigated with raw wastewater. This was much lower than the permissible PO4 amount for discharging the effluents to the surface water resources (6 mg/L PO4 is permitted by Iranian Environmental Protection Organization).
A. Azizian, A. R. Sepaskhah, A.r. Tavakoli, M. Zibaee,
Volume 10, Issue 4 (1-2007)
Abstract
Irrigation water Scarcity is the major limiting factor for crop production in irrigated farming. Therefore, optimal use of water is influenced by seasonal rainfall especially where the water price is high. Nitrogen also plays a key role in plant nutrition. In this study, wheat grain yield production as a function of applied water (irrigation plus seasonal rainfall) and nitrogen fertilizer (applied plus soil residual nitrogen) using existing data of a field experiment, were used. This function was obtained based on the data from the Maraghah Agricultural Experiment station. Based on this production function, maximum attainable yield can be 8.12 t/ha obtained by the consumption of 1.56 m of water (irrigation plus rainfall) and 193 kg/ha of nitrogen. An economic analysis based on the Iso-Quant curve was conducted to optimize the application rates of production inputs (water and nitrogen). When land is limited, the optimum water and nitrogen use will be based on maximizing net returns from land unit area. The optimal levels of these inputs were determined on the basis of farmer ability for paying the costs of water and nitrogen. Furthermore, optimum amounts of water and nitrogen were determined for different levels of wheat yield. The results indicated that despite low price of irrigation water and nitrogen fertilizer, at present market value, optimum values of water were more variable than those of nitrogen, for its high effective role in wheat production. The results also indicated that when there is no limitation of the source and use of water and nitrogen, and farmers are also able to pay their costs, application of 1.47 m of water (irrigation plus rainfall) and 190 kg/ha of nitrogen (applied plus soil residual) will produce maximum profit per hectare, reaching Rls 12,207,506. When water is limited, optimum levels of water and nitrogen will be based on the maximizing profit per unit of water. In this analysis, the use of 0.556 m of water (irrigation plus rainfall) and 190 kg/ha of nitrogen (applied plus soil residual) resulted in maximum net income per unit of applied water (irrigation plus rainfall) amounting to Rls/m3 1203. This amount of water use, which is 64.4 % lower than its amount under maximum yield condition, resulted in 181 % increase of cultivated area. Graphic expansion path on the isolines of yield showed more dependence of wheat production on water than nitrogen. Therefore, the optimum amounts of nitrogen in the three mentioned conditions are close to each other due to its subsidized price and lower effect on wheat production relative to water.
A. Ghanbari, J. Abedi Koupai, J. Taie Semiromi,
Volume 10, Issue 4 (1-2007)
Abstract
A field study was conducted at the Zabol Agricultural Research Center during the years (2003-2004) to investigate the effect of irrigation with treated municipal wastewater on the yield and quality of wheat and some soil properties. Irrigation treatments were: T1: Irrigation of wheat with well water during entire period of growing season T2: Irrigation of wheat with well water until the begging of flowering stage, and irrigation with wastewater in every other turns of irrigation T3: Irrigation of wheat with well water until the beginning of booting stage, and irrigation with wastewater in every other turns of irrigation T4: Irrigation of wheat with well water until the begging of tilling stage, and irrigation with wastewater in every other turns of irrigation and T5: Irrigation of wheat with wastewater during entire period of growing season. A complete randomized block design with four replications was adopted for this experiment. The soil was sandy loam with no limitation for internal drainage. Chemical and physical aspects of soil were measured during the experiment. Grain yield, yield components and chemical composition of wheat grain were also measured. The results showed that yield of wheat and total biomass production were statistically significant in T3, T4 and T5 compared with the control treatment. Plant height, width and length of flag leaf, numbers of fertile tillers, length of panicle, numbers of grains per panicle and weight of 1000 grains were also statistically significant with the control treatment. Percentages of protein were statistically different among various irrigation treatments. No significant changes in accumulation of heavy metals in soil and plant grains were observed. The increase of SAR, ECe, O.C% and total nitrogen in the T4 and T5 were statistical significant compared with the control treatment. In summary, for sustainable use of Zabol municipal wastewater, the growth stages of wheat should be irrigated with municipal wastewater and other growth stages should be irrigated with nonsalinty water, so that the maximum yield is obtained and soil salinitisation and sodication is prevented.
N. Etemadi, K. Razmjoo, A. Khalighi, Z. Zamani, H. Lesani,
Volume 10, Issue 4 (1-2007)
Abstract
Turfgrasses are the most important cover plants in the world. Quality evaluation of the turfgrasses is usually done by experienced evaluators using color texture, density and uniformity. The results obtained by different evaluators may be different, leading to researcher’s concern. Therefore, some quantitative methods have been used for increasing the aquracy and stability in results. In this study, three color evaluating methods including, spectrophotometery (chlorophyll content), chlorophyllmeter SPAD-502, and evaluator person, as well as leaf texture by evaluator person compared with leaf width were used for 75 populations of Cynodon dactylon L. and Tifdwarf cultivar. The results showed that there were significant differences between populations for the color and leaf texture. There were no significant corelations between measuring color by using specterophotometery, chlorophyllmeter-502, and evaluator. Use of SPAD-502 instrument for measuring leaf color of bermudagrass is not recommended due to small leaf width of this species. However, there was significant corelation between visual evaluation and leaf width in measuring leaf texture. Therefore, when no experienced evaluator is present, leaf width maybe used for measuring leaf texture.
S. Eshghi, E. Tafazoli,
Volume 10, Issue 4 (1-2007)
Abstract
Today, the production of disease-free and identical rootstock seedling in protected environments is a common practice in citrus industry. The process is time consuming, laborious and expensive. Shortening the period to reach suitable size for budding results in the reduction of the costs. It is possible to shorten the period for budding in citrus seedlings through the application of growth regulators. As lime is used widely as a rootstock in Southern Iran, this research attempted to study the effect of paclobutrozol (PP333), ethephon and pinching following gibberellic acid (GA3) treatment on height, diameter and budtake of lime seedlings. To do the research, seedlings with 4-6 leaves were sprayed with 100 mg/L GA3. After GA3 treatment, uniform seedlings 50 cm height were selected, potted and sprayed with PP333 (500 and 1000 mg/L), ethephon (150 and 300 mg/L) or pinched. All treatments, compared with control, increased height, diameter and fresh weight of shoot significantly. GA3 alone caused internode elongation. The effect of all treatments on the number of node, fresh and dry weights of root was not significant. Ethephon reduced chlorophyll content of leaf. And ethephon (300 mg/L) and PP333 (1000 mg/L) reduced budtake percentage of lime seedlings.
Z. Adavi, M. Mobli, K. Razmjoo, E. Landi,
Volume 10, Issue 4 (1-2007)
Abstract
In order to study the effects of salinity of irrigation water on the growth and quality of 10 bermudagrass cultivars under saline soil, a factorial plot experiment using a complete randomized block design with three replications was carried out at College of Agriculture, Isfahan University of Technology in 2002-2003. Ten cultivars under five levels of irrigation water salinity (3.30, 6.93, 10.2, 14.8, 17.8 dsm-1) were studied. During experiment, visual appearance of color (1 to 9, best 9), and leaf area, shoot and root dry weights and length and number of stolones were measured. Results showed that salinity of irrigation water affected color of different cultivars, such that with increase in the level of salinity, color decreased. Cultivars showed better color in August, but lower color in January. Annual mean indexes showed that ISF2 and Tifdwarf had highest and lowest color, respectively. Also, with increase in salinity levels, leaf area, foliage dry weight, length and number of stolones reduced. With increase in salinity of irrigation water from 3.30 to 10.2 dsm-1 root dry weight increased, but reduced in higher salinity levels. Due to significant interaction effects between salinity and cultivars for most traits, the responses of cultivars were different. Large differences observed between cultivars for most of traits indicated high genetic variation among the studied bermudagrass cultivars. Under high level of salinity conditions, JP2 and Tifway for foliage dry weight, 3200W18-4 and ISF2 for root dry weight, and cultivars Midlawn and 3200W18-4 for leaf area, were recognized as more tolerant than others.
M. Mojtabaie Zamani, M. Esfahany, R. Honarnejad, M. Alahgholipour,
Volume 10, Issue 4 (1-2007)
Abstract
Relationship between grain filling rate , grain filling duration, yield components and other physiological traits of rice was investigated in 93 genotypes of rice at Rice Research Institute of Iran (Rasht, Iran) during the growing season of 2001-2002. The experiment was performed without any statistical design. Panicles of main stem were tagged and taken at 3- day intervals during the grain filling period. A cubic polynomial model was used to fit the grain dry weight data (mean of R2= 0.98 for all genotypes) and the grain filling rate and duration estimated for the genotypes. Traits related to sink capacity such as grain weight, grain size and grain number per panicle correlated with grain filling rate but source -capacity- related traits except chlorophyll content of flag leaf and secondary leaf did not correlate with grain filling rate. Stepwise regression showed that final grain weight, grain filling duration and flag leaf angle contributed to grain filling rate, however, path analysis showed that only final grain weight and grain filling duration had the greatest effect on grain filling rate. The results of stepwise regression irrespective of final grain weight showed that chlorophyll content of flag leaf, grain width, grain filling duration and grain length contributed to grain filling rate. Path analysis results showed that the final grain weight had the greatest direct positive effect on grain filling rate, while grain filling duration had negative effect on grain filling rate.
Sh. Sarikhani, K. Razmjoo,
Volume 10, Issue 4 (1-2007)
Abstract
In order to evaluate the effect of row and plant spacings on the yield and yield components of three cultivars of forge sorghum, a field experiment was conducted in Isfahan University of Technology, Lavark, during spring, 2001. Experimental design was a split-factorial with three replications. Main plots consisted of three row spacings (45, 60, 75 cm) and subplots were combinations of three cultivars of forage sorghum(cultivars KFS1, IS722, IS3313) and three plant spacings (4, 6 and 8 cm). The results showed that the number of young and adult tillers, the number of leaf per square meter and shoot and leaf dry weight were influenced by row and plant spacings and significantly decreased with increasing row and plant spacings. Forage yield also decreased with increasing row and plant spacing. The highest dry forage yield was produced by 45 cm row spacing and 4 cm plant spacing. The KFS1 cultivar produced more forage yield than IS722 cultivar. The number of young and adult tiller per square meter and the number of leaf per square meter were significantly (p< 0.01) influenced by the interaction between row spacing and cultivar, row spacing and plant spacing and plant spacing and cultivar in two cuts. Shoot and leaf dry weight (kg/m2) was also significant (p< 0.01) influenced by the interaction between row spacing and cultivar, and between plant spacing and cultivar in the second cut. The density of 45 cm row spacing and 4 cm plant spacing produced the maximum forage yield.
S. Sharif, M. Saffari, Y. Emam,
Volume 10, Issue 4 (1-2007)
Abstract
Many experiments have been carried out to alleviate the negative effect of drought stress and to obtain suitable growth under water deficient condition. Application of plant growth regulators (especially growth retardants) is one of the proposed methods. In a greenhouse experiment using a completely randomized block design with 4 replications at Kerman University Agricultural Department, the effect of 4 drought levels 25, 45, 65, 85 percent of field capacity and 3 different concentrations of chlormequat chloride 0, 1500, and 3000 mg/liter on some factors of winter barley cultivar Valfajr was investigated. Results indicated that increasing the cycocel concentration from 0 to 3000 milligram per liter leads to significant decrease in plant height. Relative water content affected by growth retardants was increased. Numbers of tillers and root and shoot dry weight, were also decreased because of applying cycocel in dry condition. The result also indicated that the root/shoot dry weight ratio, grain number per ear and ear number in dry condition without stress would increase using cycocel treatment.
H. R. Ali Abbasi, M. Esfahani, B. Rabiei, M. Kavousi,
Volume 10, Issue 4 (1-2007)
Abstract
Effect of nitrogen (N) fertilizer levels and its split applications on yield and yield components of rice (Oryza sativa L.) Cv. Khazar was investigated in a completely randomized block design with 3 replications in a paddy light soil at Guilan province, Iran, 2003. In this experiment, six treatments including: T1-control (no N fertilizer) T2- 40 kg/ha N (at transplanting time) T3- 80 kg/ha N (at transplanting, and tillering times) T4- 80 kg/ha N (at transplanting, tillering, and panicle initiation times) T5- 120 kg/ha N (at transplanting, and tillering times) and T6- 120 kg/ha N (at transplanting, tillering, and panicle initiation times) were compared. Results showed that the highest fertile tiller number was obtained in the fifth and sixth treatments with double and triple split applications of 120 kg/h N (236 and 248 m-2). The highest fertile filled spikelets percentage (84.8%), 1000-grain weight (26.1 g) and grain yield (4.83 t/ha) belonged to the sixth treatment, but grain yield and 1000-grain weight were not significantly differerent in the fourth and sixth treatments with three fertilizing times. This finding may have resulted from the third topdressing application of nitrogen fertilizer in panicle initiation and higher leaf area (44.8 and 45.5 Cm2), leaf greenness (39.4 and 39.9) and leaf nitrogen concentration (31.2 and 33.6 g/kg) during grain filling in the fourth and sixth treatments. Regression analysis also showed that flag leaf greenness (SPAD values at 5 days after flowering) and flag leaf area accounted for about 75% and 78% changes in yield, respectively. In conclusion, triple split application of 80 kgN/ha could be suggested for rice Cv. Khazar in these regions since the yield would be the same as the application of 120Kg/ha N.
