Journal of Agricultural Sciences and Natural Resources
Year:2006 | Volume:13 | Issue:3|Papers Count:17

In order to study the effect of planting date and nitrogen on yield and seed yield components of dill, an experiment was conducted in 2004 at the experimental field of Shirvan Agricultural College. The experimental design split-plot in the basic of randomized complete blocks with four replications was used. Main plots consisted of three planting date (10 Mar., 13Apr. and 28 Apr) and sub-plots included four nitrogen levels (0, 40, 80 and 120 kg/ha). The results showed that planting date, nitrogen levels and their interaction had significant effect on measured traits, except for 1000-seed weight. Delaying in planting date number of umbel per plant and umbelet per umbel, seed yield, plant height, and biologic yield and harvest index significantly reduced but number of seed per umbelet significantly was increased. Except for the number of seed per umbelet that reduced by application of nitrogen was other mentioned traits were significantly increased. In the case of number of umbel per plant, number of umbelet per umbel, number of seed per umbelet, seed yield and index harvest were not significant difference between levels of 80 and 120 kg/ha nitrogen. Among the all evaluated traits the number of umbel per plant had highest correlation with seed yield. In all, the maximum seed yield was obtained at the frist planting date and 80 kg/ha nitrogen applications.

The clay mineralogy is useful to understand the soil genesis and weathering processes. This study was conducted to investigate the composition and evolution of clay minerals in the loess deposits and paleosols of Ghapan region in Golestan province. Through field observations and identification of trench, all horizons in these soils were selected for mineralogical studies. Soil and parent material samples were analyzed by XRD, after necessary pretreatments. The results revealed that in the parent material of the surface section did not detected, while smectite and mixed mica-smectite were observed in the soil samples, due to high weathering in paleosol samples. These expanding minerals have formed by transformation of illite, according to decrease of illite in soil sample, compared to parent material. Presence of palygorskite in the 7th section, in spite of its absence in the loess, indicated in situ formation of this clay mineral under high pH and Mg/Ca ratio conditions. Smectite, in 14th section, has formed ontogenetically, and also inherited from parent material, whereas in the other sections inherited from parent materials and by transformation of illite. High amount of smectite in buried paleosols compared to loess deposits probably indicates moisture regime through interglacial compared to glacial periods.

The objective of this study was to determine the inheritance of number of pods per peduncle, its linkage and effects on other characters in chickpea. Inheritance of number of pods per peduncle was studied using single podded kabuli type cultivar ICCV2 and desi type JG62 with double podded chickpea cultivars. The experimental materials comprised 126 F10 RILs, parents, F1 and three checks in Alpha design with three replications. In addition four generations F1, F2, BC1P1, and BC1P2 were planted in an unreplicated design. The experiments were conducted at the International Crops Research Institute for the Semi-Arid Tropics (ICRISAT), during the Rabi season 1998-1999 and 1999- 2000. Fz population produced 237 single podded and 68 double-podded plants. The results gave a good fit to the expected 3:1 ratio for single pod and double pod. The inheritance of pod number per peduncle was also studied in RILs and BC1P2 generations. Of the 116 recombinant inbred lines (RILs) 59were single podded and 57 were double podded and in BC1P2 these were 15 single podded and 22 double-podded plants. The results for RILs and BC1P2 show a good fit to the expected 1:1 ratio for single pod and double pod. The F1 and BC1P1 generation had single pod per peduncle. These results indicate that the number of pods per peduncle is controlled by single gene, and single podded is dominant to double podded plants. The estimate of chi-square for joint segregation between number of od per peduncle with flower color, seed surface, stem color, seed type and seed coat color revealed lat theses traits segregate independently. The result of present study indicate the absence of Significant differences for number of pods per plant, number of seeds per plant, 100-seed weight and Seed yield per plant in single and double-podded genotypes.

To evaluate the interaction of salinity and nitrogen nutrition on vegetative growth, canola Brassica napus var. PF7045/91 was cultivated in greenhouse in sand culture. The experiment conductedin completely randomized blocks with factorial treatment arrangement with 5 replication. Factor one was nitrogen source including nitrate, ammonium and nitrate plus ammonium (with 5/6 ratio) and the second factor was salinity with three levels including 0, 50 and 100 mM Nacl. Plants harvested at the end of vegetative growth (code No.3.5 Sylvester-Bradley and Makepeace) after 70 days treatments and dry weight, leaf area and concentration of Na+, K+, Cl-, total amino acids and total N were measured. The highest growth under salinity was observed in nitrate fed plants in compare to other nitrogen treatments. Plants fed with ammonium indicated highest sensitivity to salinity that reflected in high decrease in dry weight and leaf area. The highest concentration of Na+ in shoot and Cl- were observed in shoots and roots of plants fed by ammonium under salinity, respectively. In nitrate treatment, the lower concentration of Na+ in shoot leads to the lower tixicity and the higher growth. Plants fed with ammonium plus nitrate indicated middle Na+ and Cl- concentration under salinity. However, decrease of K+ concentration was not significant in this treatment. As a result, vegetative growth of ammonium plus nitrate fed plants was in the middle of nitrate or ammonium as sole nitrogen source.

To study the phenotypic and genotypic diversity some of important agronomic traits associated with yield in 15 genotypes of red beans were evaluated in a randomized complete block design with 3 replications on two environments under the water stress and non stress conditions in Mashad Agricultural Research Station in 2003. In study 14 morphological traits related to yield were evaluated. Analysis of variance showed that there were significant differences among varieties in terms of traits under study, indicating the existence of genetic variation among varieties. The results indicated that seed yield, number of seed per plant, weight of pod, harvest index, number of pod and biological yield in red been reduce under condition of stress whereas, evaluation of drought resistance in bean genotypes, showed that stress tolerance index (STI) and geometric mean productivity (GMP) were the best criteria for recognizing tolerant genotypes (Kh-31168, Kh-31165 and Kh-31166). In non-stress condition, yield was highly correlated with the biological yield. Whereas in stress condition it was highly correlated with harvest index in red bean, factor analysis was accomplished in non stress and water stress conditions. There were 5 factors that explained 74 percent in non stress condition and 73 percent of total variations in stress condition. Results of stepwise regression and path analysis showed that, selection can we done based on harvest index, biological yield, number of pod per plant, number of seed per pod number of seed per plant, 100-seed weight. Results of path analysis showed that the highest direct effect, being positive, was related to biological yield in non stress and to harvest index in stress conditions. In classification of genotypes base on phenotypic characteristics climates, using cluster analysis (UPGMA), and all genotypes classified in 4 separate groups in non stress and stress condition.

Increasing the salt tolerance of sugarcane (Saccharum officinarum L.) is an important goal due to the semi-arid climate and salinity stress of its cultivation area in our country. An experiment was carried out to determine the effect of sodium chloride on morphological characteristics of eight commercial and promising sugarcane cultivars at formative stage using 0, 0.25, 0.5, 0.75 percents NaCl in a hydroponics system. The results showed significant differences among the cultivars for all traits at different salt levels. Increase of salinity concentration decreased growth of sugarcane cultivars and their traits such as: dry weight, plant height, tiller numbers, leaf area and leaf number per plant. But the trend of reduction was slower for tolerant genotypes. Number of green leaves and number of tiller per plant had the highest percentage of decrease and leaf width and total number of leaves percents had the lowest one. CP65-392 cultivar identified as the most sensitive genotype at this growth stage because of its death at all salt levels. NCO-310 as a cultivar with high yield potential at non stress and low stress conditions had the highest growth rate at zero and 0.25% NaCl salt levels. At medium and high salt levels CP72-2086 and CP82-1592 genotypes had the highest growth rate and dry weight, respectively. Although these two cultivars had lower yield than NCO-310 at nonstress conditions, they had more salt tolerance potential. Therefore, these two cultivars seem to be beneficial in sugarcane breeding program due to their higher production under salinity stress condition. Assessment of sodium and potassium concentrations revealed that NCO-310 and CP82-1592 ranked as the most tolerant genotypes, having the highest potassium to sodium ratio, respectively.

In order to evaluate the effects of the amount and application time of nitrogen fertilizer on growth, physiologic characteristics, yield and yield components of wheat (Tritium aestivum. L. cv. Zagroos), an experiment was conducted under rainfed condition at Gorgan province, Iran in 1999-2000.The treatments consisted of the factorial combination of five nitrogen rates (N1=0,N2=30, N3=60,N4=90 and N5=120 Kg.N/ha-1) and four different time of nitrogen application, which were T1= all preplant (Pp), T2= 1/3pp + 2/3 tillering, T3= 1/3pp + 2/3 stem elongation and T4= 1/3pp + 1/3 tillering+1/3 stem elongation. The experiment was arranged as a randomized complete block design with three replications. The results showed that grain and biologic yields increased second order polynomial with increasing N fertilizer. The highest grain yield and biologic yield were observed in N4treatmentwith 4525.1 and 10386.6 kg/ha-1 respectively. The increase in grain yield with increasing N application was due to increase in spicule/m-2 and grains. spicule-1. The plant height, TKW and spicule-2 were significantly affected by the time of N fertilizer application at 5% probability level.

To study the effects of nitrogen fertilizer forms on dry matter and nitrogen remobilization, yield, and yield components in rice cultivars, a field experiment was carried out in Geshnian village (Marvdasht) in 2002. A split-plot layout based on randomized complete blocks design with four replication was used. Three nitrogen fertilizer form, including ammonium sulfate, ammonium nitrate and urea were used as the main plots and three rice varieties including Nemat, Dorodzan and Comfiroze were used as the sub plots. The results showed that grain yield, fertilized tiller number, biomass, plant height, panicle length, fertilized panicle percentage, grain protein percentage and nitrogen remobilization from stem and leaves were significantly affected by different forms of nitrogen fertilizers. Also all characters had significant differences among rice varieties. Moreover, the interaction between nitrogen fertilizers and rice cultivars had significant effects on fertilized tiller number, biomass, plant height, fertilized panicle percentage grain protein percentage, nitrogen and dry matter remobilization from stem and leaves. Urea fertilizer had the highest grain yield, fertilized tiller number, biomass, plant height, panicle length, grain numbers per panicle, grain protein percentage, nitrogen remobilization from stem and leaves. Nemat variety showed the highest grain yield, plant height, panicle length, grain numbers per panicle, nitrogen and dry matter remobilization from stem, leaves and flag leaf. In general, contribution of grain dry matter from stem was more than other parts (flag leaf and other leaves). But leaves of Nemat variety remobilized more nitrogen than stem under all conditions. Dorodzan variety had the least biomass, nitrogen and dry matter remobilization from stem, flag leaf and other leaves but this variety had the highest grain protein percentage. There were positive and significant correlation between grain yield, fertilized tiller number, biomass, plant height, panicle length, grain numbers per panicle, fertilized panicle percentage, nitrogen remobilization from stem and leave and dry matter remobilization from leaves.

Irrespective of technological advances in agriculture, still climate is the most important yield determinant factor. The objective of this study was to quantify the probability of occurrence of thermal stresses at different growth stages of cotton at Gorgan (the North of Iran) environmental conditions. To do this, first growing degree days requirement for different developmental stages were computed. Then, using 40 years daily weather data of Gorgan and a computer program, prepared for this study, the probability of occurrence of different stressful temperatures for different processes (like emergence and photosynthesis) were calculated. The results showed that cotton encounters low stressful temperatures during emergence, leaf production during vegetative growth at early sowing and fiber growth at late sowing. However, high temperature stress decreases photosynthesis and flower and boll retention from squaring to bolling stage at late sowing. During vegetative stage, both low and high temperatures limit the photosynthesis of the crop. The results of this study can be used in cultural management and breeding of cotton and in designing stress physiology researches.

In order to evaluate the allelopathic effects of canola extract and stubble on germination and growth of corn and soybean seedlings, three experiments were conducted using a factorial arrangement in a randomised compelete block design with four replications in greenhouse and laboratory of college of agriculture, University of Gorgan in 2004. The treatment of one greenhouse experiment consisted of: plant species (corn and soybean) and the amount of canola stubble (0%, 0.35%, 0.71%) and stubble (w/w) based on percentage of soil dry weight. The second experiment was conducted in laboratory and the third one was conducted in greenhouse. The factors consisted of: plant species (corn and soybean) and canola concentration (5%, 10%, 15% and control). Increasing the amount of stubble and extract concentration of canola decreased the rate and maximum emergence percentage of corn and soybean, but the observed changes were not significant. The results showed that stem height, root length, leaf area, root and shoot dry weight in 5 and 15 days after emergence were not affected with respect to control. But in 10 days after emergence, the increase of canola extract concentration and stubble decreased root length and root dry weight of soybean, respectively. Also increasing of extract concentration of canola significantly decreased corn rate and maximum germination percentage in petri dishes. In general, the results suggest that canola extract and stubble at the levels used in this study do not show significant effect on emergence and early growth of corn plant.

Charcoal rot caused by Macrophomina phaseolina is one of the most prevalent and destructive disease of soybean in Mazandaran and Golestan provinces. During 1991-2003, soybean fields of Eastern Mazandaran were surveyed and collected samples showed signs on the stems and roots. The suspected samples were cultured on PDA medium. All of the isolated colonies were identified as Macrophomina phaseolina. The pathogen city tests were carried out under greenhouse conditions, using artificially infested soil by the fungus propagules (sclerotia) and the fungus was pathogenic on soybean. Various isolates of soybean, sunflower, and sesame had different growth, colour, size, and number of sclerotia on PDA medium. Reaction of the cultivars and advanced lines of soybean were evaluated by fungus infection under field conditions. The results showed that Gorgan3 cultivar and J.K-695 and B.P-692 lines had minimum infection. The infection rates of the disease were 50-60% in Goibar, and less than 10% in Amol regions. Average numbers of the fungus sclerotia were rated equal to 32 in Goibar, and 14 in Ghaemshar regions.

In order to identify Fusarium species associated with root and crown rot of potato, several Field in different region of Gorgan were sampled during growing season (2003-2004). For isolation of fungi, some parts of diseased tissue (root and crown) were surface sterilized with sodium hypochlorite 5% and washed three times with sterile distilled water, and then placed on acidified potato dextrose agar. From diseased tissue 35 isolates of Fusarium spp. were isolated and purified by single spore. By valid books of Fusarium species identification of five species: Fusarium oxysporum, F. equiseti, F. moniliforme, F. solani and F croockwellnse were identified, with 22.85, 8.57, 14.28, 42.5, 11.42 frequency percentages respectively. Fusarium solani was the most abundant one. Pathogenicity test was performed by inoculation of spore suspension (2x106) on root and crown of 25 days old plants of marfona potato cultivar. The result showed that pathogenesis of all fungal isolates of F.solani except oneisolates and all isolates of F.oxysporum, F.moniliforme, Fcroockwellnse and F.equiseti performed root necrosis in mainroot and their branched. In relation to those species of F.oxysporum and F.solani colourchanges of vascular tissue was observed after inoculation on crown part of potato. This study was the first report of Fusarium on potato in Gorgan area.  

Morphology, biology, efficiency and behavior of Eretmocerus mundus (Mercet) were studied on the silverleaf whitefly, Bemisia argentifolii Bellows & Perring in Isfahan province. The body length of male and female were 0.68±0.01 and 0.78±0.04 mm, respectively. Female's antennal clava with 7-8 sensilla and for males is 80-100 ones. Seven life stages including, egg, 3 larval instars, pre-pupa, pupa and adult were identified for the parasitoid. Second and 3rd nymphal stages of the host were preferred. The parasitoid puts its eggs below the nymph; first larval instar enters into the host body and develops as endoparasitiod. Developmental life stages from egg to pupa were 3.91±0.58, 1.83±0.42, 3.58±0.58, 5.08±0.2 and 3.5±0.54 and 8.33±1.08 days, respectively. Host hemolymph and solution of 15% honey syrup caused the highest effect on longevity and efficiency of parasitoid. The mated females had more longevity and fecundity than unmated ones. All the virgin females of E.mundus produced only male off springs. Sex ratio was 1:1 in cultures but in nature varied in different months and on the host plants. The rate of female was always more than males, and the highest was on Lantana camara and Convolvulus arvensis in middle of September. Super parasitism and self - super parasitism were not observed for E. mundus. There was not found any efficient hyperparasitiod for the parasitoid in Isfahan province.

Two moth old oak seedlings (Quercus robur) grown in controlled conditions were submitted to water logging for one to three months, then plant were drained to assess recovery for two months. Kinetic analysis showed that shoot growth was drastically inhibited on oak seedlings. Elongation rhythm immediately disappeared after the beginning of water logging. When stress was maintained for three months, Q. robur seedlings were able to renew a shoot rhythmic growth during the water logging stage. But leaf, shoot and root biomass, and surface area were reduced by water logging. During drainage, a strong biomass recovery was observed. Thus, in terms of growth and development, Q. robur seedlings were able to cope with water logging and recovery was quite complete after two months of drainage. This related with the higher plasticity of the root system of Q. robur: (i) new roots fastly developed above the water table and (ii) histological change occurred in root with development of parenchyma. Comparisons between data were performed with a Statistical analysis non-parametric Mann and Whitney (Statview, SAS Institute Inc., Cary, NC, USA).

Efficacy in estimation of storage coefficient in Clark method, as one of the applicable techniques for development of instantaneous unit hydrograph, may have great effect on ultimate unit hydrograph. The present study was therefore conducted in Bazoft watershed in Chaharmahal and Bakhtiari Province to determine the efficiency of developed hydrograph using Clark method and to compare the Muskingum storage coefficient obtained through graphical, Clark and Linsley methods. Firstly, the time-area histogram of the watershed was developed. The 2h-unit hydrograph was then derived using the data collected in Chelgerd climatological and Morghak hydrometric stations. The efficiency of Clark's instantaneous unit hydrograph developed based on graphical, Clark and Linsley methods for calculation of Muskingum storage coefficient was ultimately evaluated. The results of the study revealed that the Clark's instantaneous unit hydrograph resulted from graphical method for estimation of storage coefficient is more compatible with average unit hydrograph existed for the watershed than other two methods.

In this study, the spatial pattern, richness, and diversity of dominant range species in protected areas of Golestan National Park and deteriorated areas of surroundings were evaluated by using PQV, TTLQV (for sedgbrush and grassland) and T-sqaure distance method (for shrublands). The objectives were to determine the spatial pattern and diversity index based on vegetation types. The effects of some environmental factors were traced to find the cause and effect of these patterns. Based on our results the relations between biological types were: TH>CH>GE>HC>CR and from standpoints of life form, the relations were Forbs>Grasses>Woody plants. Grasslands were richer than shrubs. In general, due to lack of rainfall and overgrazing, the unpalatable cushion and annual species were increased, so the richness of rangeland was high in deteriorated areas. In protected areas due to nonuse, lack of competition, diversity decreased. Spatial pattern due to the dominant species were not detected but the spatial pattern of the same dominant species at local scale were random or clumped. In community the clumped pattern were detected for Artemisia herba Alba. In shrublands the nested pattern of clumped within random or regular were determinated.

In assessment of recycling Gorgan Household Solid Wastes (GHSW), physical analysis of the household refuses has been performed monthly in 2001 by the random method. Suggesting amount of recyclable materials according to daily products of GHSW, components of the GHSW are determined upon their sizes, compositions, density, and moisture. The results of physical analysis of GMSW depict the amount of compost able materials with the highest content (74.62%), plastics (13.88%), paper (7.7%) and remaining material (3.73% which contains metal, 0.799%; wood, 0.136%; glass, 1.51%; textiles; 1.17%; others, 0.177%). According to the production of about 200 tons/day GHSW, the compost able recycling materials is estimated about 149.25 tons/day, plastics 27.7 tons/day and paper 15.40 tons/day; So that by the improvement of GHSW management, the recycling of these refuses could be accessed.