Tarbiat Modares UniversityJournal of Agricultural Science and Technology1680-70738320060701Measuring the Static and Dynamic Cutting Force of Stems for Iranian Rice Varieties19319815271ENR.Tabatabaee KoloorDepartment of Agricultural Machinery, University of Mazandaran, Sari, Islamic Republic ofIran.A. M.BorgheieDepartment of Agricultural Machinery, College of Agriculture, University of Tehran, Karaj, Islamic
Republic ofIran.Journal Article19700101In order to help in the engineering design of rice harvesting machines, there is a need to have exact information concerning the physical and mechanical properties of rice stems. The cutting force for rice stems, therefore, was measured by designing and fabricating a static and dynamic shear test apparatus. The effects of moisture levels and the cross-sectional area of stem as well as the variety, blade bevel angle, blade type and cutting speed on shearing strength have been evaluated. The results indicated that the cutting force increased with an increase in the cross-sectional area and decreased with an increase in moisture content. The static and dynamic shearing strength was different among the varieties. The maximum and minimum shearing strengths were related to the varieties Khazar and Hashemi, with an average of 1629 and 1429 kPa for static test and values of 187.4 and 144 kPa for the dynamic test, respectively. The shearing strength decreased from 234.4 kPa to 137.4 Kpa with an increase in blade cutting speed from 0.6 to 1.5 m/s. Blade bevel angle and blade type had no significant effect on the shearing strength of rice stem.https://jast.modares.ac.ir/article_15271_2a174f994bb16b9b11e6ea5c00a671c5.pdfTarbiat Modares UniversityJournal of Agricultural Science and Technology1680-70738320060701The Effect of Salinity on Growth, Inorganic Ions and Dry Matter Partitioning in Sugar Beet Cultivars19921015272ENA. R.DadkhahFerdowsi University, Mashhad, Islamic Republic ofIran.H.GrrifithsUniversity of Cambridge, Cambridge, England.Journal Article19700101This study investigated intra-specific variation in the growth parameters and dry mat-ter partitioning of sugar beet cultivars at different levels of salinity (0, 50, 150, 250 and 350 mM NaCl + CaCl2 in 5:1 molar ratio) using four cvs, one British (Madison) and three Iranian cvs (7233-P12, 7233-P21 and 7233-P29). The plants were grown in a controlled greenhouse environment for about 18 weeks. Although growth parameters such as leaf area and dry matter accumulation were stimulated or unaffected at a low level of salinity (50 mM), higher salt concentrations significantly decreased all growth traits. At a high level of salinity, cv P29 showed a significantly higher leaf area and total dry matter than others at 16 weeks of salt treatment. Pre-dawn leaf-water potential (ΨL) and shoot water content (SWC) were decreased by salinity. Cvs Madison and P12 had significantly lower ΨL (more negative) and shoot water content at high levels of salt treatment (250 and 350 mM), while P29 and P21 showed higher ΨL (less negative) and shoot water content at the same salt concentrations. Analysis of ion accumulation revealed that Na+ and Cl- contents were greatly increased in leaves under saline conditions. However, salt tolerant P29 had lower Na+ and Cl- concentrations than other cvs at high levels of salinity. The root dry matter of sugar beet cvs at the lowest and the highest salt concentrations reduced by 23.3% and 89.8%, respectively compared to the non-stressed plants, while shoot dry mat-ter decreased by 1.1% and 77% at the same salt concentrations, respectively, after 16 weeks of salt treatment. The pattern of dry matter partitioning to different parts of the plant was changed by salt stress and the dry matter allocated to the storage roots was re-duced by 6% and 18% at the lowest and the highest salt concentrations, respectively, at 16 weeks after salinisation.https://jast.modares.ac.ir/article_15272_0fcbc3c0cf262c771001930af2406bbc.pdfTarbiat Modares UniversityJournal of Agricultural Science and Technology1680-70738320060701The Effects of Water Deficit on Crop Yield and the Physiological Characteristics of Barley (Hordeum vulgare L.) Varieties21121915273ENE.MamnouieFaculty of Agriculture, University of Guilan, Rasht, Islamic Republic ofIran.R.Fotouhi GhazviniFaculty of Agriculture, University of Guilan, Rasht, Islamic Republic ofIran.M.EsfahaniFaculty of Agriculture, University of Guilan, Rasht, Islamic Republic ofIran.B.NakhodaSeed and Plant Improvement Institute, Karaj, Islamic Republic ofIran.Journal Article19700101The effects of water deficit on grain yield, yield components and the physiological char-acteristics of barley (Hordeum vulgare L.) varieties were studied in a split plot design dur-ing the 1999-2000 growing season in Karaj, Iran. Five irrigation levels [0, 25, 50, 75, and 100% crop water requirements (CWR)] and six barley varieties Karoon Kavir , Rei-hani(drought tolerant), Torkman , C-74-9 (intermediate) , Kavir Badia and Gorgan-4 (2 rowed type, drought sensitive) were arranged in the main plots and sub plots respectively. Results showed that water deficit induced stress and this decreased the grain yield and yield components. Water deficit increased the canopy temperature and those varieties showed a higher canopy temperature under non-stress conditions, performed better un-der drought conditions. Severe stress reduced the chlorophyll content (SPAD values) con-siderably, but the differences were not significant between the 50, 75 and 100% CWR treatments. In addition, no significant differences were observed in the chlorophyll con-tent of barley varieties under drought conditions. The effect of irrigation on the photo-chemical efficiency of photosystemII (Fv/Fm) and the other fluorescence parameters for all varieties were significant. Although the Fv/Fm values were not significant in barley varie-ties at any level of irrigation, in general Karoon Kavir and Reihani varieties showed a better performance under water deficit conditions. Proline content was significantly dif-ferent in various irrigation treatments, but its accumulation at any level of irrigation did not differ significantly in barley varieties. It was concluded that the higher canopy tem-perature (less negative T) under well irrigated conditions and higher grain yield, 1000-grain weight, Fv/Fm values under water stress conditions could possibly be the proper cri-teria for screening the drought tolerant barley genotypes under field or laboratory condi-tions.https://jast.modares.ac.ir/article_15273_2e64b43ae33b6a9c6718e03b11f7f24c.pdfTarbiat Modares UniversityJournal of Agricultural Science and Technology1680-70738320060701The Effect of Altitude on Juvenile Wood Formation and Fiber Length, a Case Study in Iranian Beech wood (Fagus orientalis L.)22123115274ENS. Z.HosseiniGargan University of Agricultural Sciences and Natural Resources, Gargan, Islamic Republic ofIran.
221Journal Article19700101The mean fiber length of three beech trees (Fagus orientalis L.) at the lower and higher points (1% and 75% tree height) of the stem at an intermediate altitude (500-1000m) in the Caspian forests in Sari region were 1.36 and 1.22mm respectively, close to the values in three trees at high altitude (1000-1500m), that were found to be 1.39 and 1.36 mm. The mean fiber lengths of the whole stem, using stem formula, were considered as 1.31 and 1.38mm at intermediate and high altitudes and so were very close each other. Juvenile wood portions in the stem comprised 17 annual rings, which took up 7.3% of the stem by volume at intermediate altitude. At high altitude, these values were obtained as 18 annual growth rings, and 8.75% juvenile wood in the stem. The reason for greater juvenile wood at high altitude was somehow a wider ring width at higher elevation. The mean ring width of lower and upper points of the stem at intermediate altitude were found to be 1.82 and 2.95mm respectively; meanwhile, at high altitude, the findings were 2.97, 3.37mm. Despite the data obtained, t- test comparison was conducted between mean fiber lengths of the two heights of the stems at two altitudes, and no significant differences were found at the 1% level. The exploitation age was strongly dependent on how much juvenile wood there was in the stems, that at high altitude was greater than at intermediate. However, statisti-cal comparison showed no significant differences between that and the 1% level. There-fore, altitude in the range of about 500m showed no important impact on beech fiber length, exploitation age or juvenile wood border in Caspian forests.https://jast.modares.ac.ir/article_15274_45d5c43856059a4f97d43d6534be52d0.pdfTarbiat Modares UniversityJournal of Agricultural Science and Technology1680-70738320060701A Dynamic Programming Solution to Solute Transport and Dispersion Equations in Groundwater23324115275ENM.MirabzadehDepartment of Irrigation Engineering, College of Agriculture, University of Tehran, Karaj, Islamic Republic of Iran.K.MohammadiDepartment of Irrigation and Drainage Engineering, Tarbiat Modarres University, P. o. Box:14115-336, Tehran,
Islamic Republic of Iran.Journal Article19700101The partial differential equations for water flow and solute transport in a two-dimensional saturated domain are rendered discrete using the finite difference technique; the resulting system of algebraic equations is solved using a dynamic programming (DP) method. The advantage of the DP algorithm is that the problem is converted from solving an algebraic system of order NC(NL-1) NC(NL-1) into one of solving a difference equa-tion of order NCNC over NL-1 steps and involving NL-1 matrix inversions of order NCNC. The accuracy and precision of the solutions are shown by comparing the results with an analytical solution and calculation of mass the balance. In addition, the perform-ance of the DP model was compared with the results of the MOC model developed by US Geological Survey. In all cases, the DP model showed good results with sufficient accu-racy.https://jast.modares.ac.ir/article_15275_783789429d08b80f58e54e2c76fd6d27.pdfTarbiat Modares UniversityJournal of Agricultural Science and Technology1680-70738320060701Evaluation of Trichoderma Isolates for Biological Control of Charcoal Stem Rot in Melon Caused by Macrophomina phaseolina24325015276ENH. R.EtebarianDepartment of Plant Protection, Abourayhan Campus, University of Tehran, P.O.Box: 11365-4117,
Tehran, Islamic Republic ofIran.Journal Article19700101Trichoderma harzianum (T39), T.virens (DAR74290), T.viride (MO), T. harzianum (M) and TrichderminB a commercial formulation of T. harzianum(Bi) were evaluated as potential biological agents for the control of charcoal stem rot in melon caused by Macrophomina phaseolina. Cell-free metabolites of T. harzianum(M), T. harzianum (T39) and T. virens (DAR 74290) inhibited growth of M. phaseolina completely in vitro and appeared to be fungicidal. T. viride (MO) inhibited fungal growth from 34.9% to 71%. T. harzianum (T39), T. harzianum (M), T. virens (DAR 74290), T. viride(MO) and T. harzianum (Bi) were tested for their ability to protect melon plants from disease caused by M. phaseolina in a glasshouse experiment. The percentage of stand plants with the antagonist alone or in combination with the pathogen was significantly (p<0.05) greater than in plants inoculated with the pathogen alone. The percentages for the stand plants in treatments were as follows: T. harzianum (T39), T. harzianum (M), T. virens (DAR 74290), M. phaseolina, M. phaseolina + T. virens (DAR 74290), M. phaseolina + T. harzianum (T39) and M. phaseolina + T. harzianum (M),at 95, 100, 97.5, 15, 64.25, 75.25 and 47.55 percent respectively. The percentage for the stand plant in the commercial Trichodermin B + M. phaseolina treatment (96.7%) was greater than for M. phaseolina alone (46.7%) and demonstrated the best result in the control of charcoal stem rot in melon.https://jast.modares.ac.ir/article_15276_e0a4794fc273e7d59334e5f4fba95f3b.pdfTarbiat Modares UniversityJournal of Agricultural Science and Technology1680-70738320060701Phosphorus Sorption Characteristics in Relation to Soil Properties in Some Calcareous Soils of Western Azarbaijan Province25126415277ENA.SamadiSoil Science Department, Unnia University, P. O. Box 165, Unnia, 57134, Islamic Republic ofIran.Journal Article19700101Phosphorus (P) sorption in soils is a key process governing its availability to crops. There has been scanty information available on the P sorption characteristics of calcare-ous soils of Western Azarbaijan Province, Iran. In this study, P sorption characteristics and their relationship to soil properties were determined in 36 soil samples belonging to 15 agricultural soil series located in the south of Urmia, Western Azarbaijan Province. Total CaCO3 contents ranged from 10 to 48.5%. Active CaCO3 contents ranged from 1.7 to 20% and were significantly related (r = 0.61, P<0.001) to the total CaCO3 of the soils. NaHCO3-extractable P contents ranged from 4 to 38 mg P/kg soil. The amount of P sorbed by the soils differed among various soil series. The results showed that equilibrium solution P concentration (EPC) was lower (<0.2 mg/L) than the requirement for most crops. The amount of P adsorbed by the soils at 0.2 mg/L EPC ranged from 5 to 114 mg/kg soil. The phosphate adsorption was well described by the Freundlich (r2 = 0.96) and Langmuir (r2 = 0.88) isotherms. The Langmuir maximum adsorption (Xm) and Freundlich coefficient (aF) estimated from Langmuir and Freundlich equations ranged from 127 to 238 mg P /kg soil and from 43 to 211 mg P/kg, respectively. Soil clay content was significantly related to the soil P sorption indices, P0.4 (P sorbed at 0.4 mg P/L, r = 0.40, P<0.01), PBC (P buffering capacity, r = 0.54, P<0.001), aF (r = 0.48, P<0.01), and Xm (r = 0.40, P<0.01). Total CaCO3 and active CaCO3 were found to be less important factors affecting P adsorption.https://jast.modares.ac.ir/article_15277_971bbe989ad132e834b0ccb3f32e92ee.pdfTarbiat Modares UniversityJournal of Agricultural Science and Technology1680-70738320060701Protein Marker Assisted Identification of Yr9, Lr26 and Sr31 Genes in a Group of Iranian Wheat Cultivars26526815278ENF.AfshariSeed and Plant Improvement Institute, P. O. Box: 4119, Karaj, Islamic Republic ofIran.Journal Article19700101The 1RS chromosome segment derived from Petkus rye carries genes for resistance to three wheat rust diseases, namely Lr26 for resistance to leaf rust (caused by Puccinia triticina), Yr9 for resistance to stripe rust (P.striiformis f. sp. tritici) and Sr31 for resistance to stem rust (P. graminis f. sp. tritici). Since Sec-1 is tightly linked with the three rust resis-tance genes electrophoresis it is a useful method to identify and confirm the presence of three rust resistance genes in current wheat populations. SDS-PAGE was used to examine eight Iranian wheat cultivars for resistance to three rusts. The eight Iranian wheat culti-vars examined were Alvand, Darab 2, Tajan, Nicknejad, Mahdavi, Zarrin, Alamoot and Atrak. The SDS-PAGE results showed that cultivars Mahdavi and Atrak have Sec-1 bands and are therefore likely to carry the 1BL.1RS translocation and the linked genes Yr9, Lr26 and Sr31.https://jast.modares.ac.ir/article_15278_6c4017cb587ae4c69bd3f3eb84dd658a.pdf