THE SCIENTIFIC JOURNAL OF AGRICULTURE (SJA)
Year:2002 | Volume:25 | Issue:1|Papers Count:13

Experiments were carried out with the aim of plantlet produced from the tissue culture of garlic cv. Saphide Shomal by means of shoot tip and callus culture. In this experiment, small sample of basal plate (S), shoot tip (M), basal plate with shoot tip (SM) and root tip ( R) were cultured after disinfecting in a MS medium with various auxin (IAA, NAA, 2,4-D) and Kinetin. The most suitable achieved disinfecting substance for the explants was bleach (Vortex) with the effective substance of 1.5 percent Sodium hypochloride for the period of 30 minutes and then, rinsing with 60 percent Ethanol alcohol for 10minutes: The highest percentage of callus in the MS medium with 1 mg/l IAA and 1 mg/l 2,4-D was established in perpetual darkness. Also, the highest callus weight increase for the basal plate explants in the MS medium contains 2 mg/l IAA, 0.5mg/12,4-D and 1 mg/l kinetin. And for the shoot tip, in MS medium supplied with 1 mg/l IAA, 0.5mgll 2,4.D and in 16 hours light (2500 Lux) was achieved. The highest percent of embryonic callus, differentiation and root formation were obtained through the callus resulting from basal plate explant which had been transferred to the MS medium with 1 mg/l IAA and 1mg/l kinetin. Also, it was observed that the differentiation cells of garlic cv. Saphide Shomal primary had produced roots.

Seasonal poplation dynamics of sweetpotato whitefly Bemisia tabaci (Gennadius) and its parasitoids Eretmocerus mundus (Merect) and Encarsia lutea (Masi) were investigated on aborigine (variety black beauty) during spring and summer 2000 and 2001 in Ahwaz southwest, Iran. Different growth stages of B. tabaci (egg, first to third larval inastars, fouth larval instar and adult) first appeared on plants in the middle of May, increased slowly in June, peaked in the middle of July in 2000 and early July in 2001, and then declined shatply. The population, were very low in September. Fourth larval instars parasitized by E.mundus and Elutea first appeard bn aubergine in the middle of May, thep population increased gradually and in 2000 and 2001 peaked in late August and middle of July respectively. After this period the popultion declined sharply. Average parasitism by Emmundus and. E lutea were 24 , %5 in 2000 and 33, 13%in 2001 respectively. The population of fourth larval instar parasitized by Emundus was on average 4.5 times (2000) and 6.9 times (2001) higher than 4th larval instars parasitized by. E. lutea. Population fluctuation of these parasitoids indicated that their population dynamics is dependent on the density of host (B.tabaci). Vertical distribution of different growth stages of B. tabaci and also fourth larval instars parasitized by E.mundus and E.lutea were not similar on different parts of aubergine plant. In general the highest density of eggs, 1 st to 3rd larval instars, fourth larval instars and adults of B.tabaci were concentrated on the middle and bottom third of aubergine plants. However, the maximum vertical distribution of 4th larval instars parasitized by E.mundus and E.lutea was on the middle part of the plant.

Bio-technique methods, use of vegetation especially tree for stability of river banks or natural slopes, have been received more attention by many river engineers nowadays. The most notable effects of tree roots are: increase of soil strength through reinforcing the soil. Roots of tree and other vegetation provide a reinforcing effect to soil through tensile resistance and frictional or adhesion properties. The reinforcing effect or increase of shear strength in soil due. to presence of root can be quantified by Barker's type equation. In this study attempt have been made to investigate the effects of two common tree species in the stability of Karoon riverbanks. For the purpose of this study, the geometry, and the characteristics of these tree roots were collected. Applying these data and a computer model, which developed for this study, the distribution of roots and the ratio of root cross-section relative to the total shear cross section were computed for any depth and distance. The maximum root tensile force measured for 59 root samples was correlated to the root diameter. Using Barker's type equation, the amount of soil shears strength for these trees was computed in different depth. The results show that the roots of tamaricaceae have increased the soil shear strength more than the populous roots especially for depth up to 40 cm. The amount of soil shear strength increased is higher for the popoluse at deeper depth and reaches to a maximum of 21.6 Kpa at depth of 150cm.

In order to study the effect of N levels and optimum plant density on grain yield of rapeseed cultivar PF7045, a field experiment was conducted in 1998-1999at Ramin Agricultural Research and Education Center, University of Shahid Charmran, Ahwaz. The design was a split plot in a completely randomized block bases with 4 replications. Main plots were consisted of 5 levels of N (45, 90, 135, 180and 225 kgN/ha) and subplots of 3 plant densities (50, 70 and 90 plants/m2). Results showed that higher applications of N fertilizer up to 225 kgN/ha increased grain yield (2980.9 kg/ha). The higher yield (2796.4 kg/ha) obtained from 90 plants/m2 denstiy. Interactive effect of N and planting density on grain yield was significant. Application of 225 kgN/ha at the highest density (90 plants/m2) produced 3301.0 kg/ha of grain. These results indicated that response of grain yield to different plant density was due to differences in N application rates. Among yield components, number of pods/m2 and number of kernel per pod showed that the highest sensitivity to both plant density and N levels. The number of pods/m2 increased with increase in N levels and plant density while the number of kernels per pod decreased with increase in N levels and plant density. 1000 kernel weight increased with N levels and decreased with higher plant density respectively. The highest of oil (45. 09%) was obtained from 45 kgN/ha at plants/m2 density and the lowest amount oil (40.0%) obtained from application of 135 kgN/ha at 50 plants/m2 density. These results showed that the effect of N levels on grain oil was more than plant density.

In this Evaluation, eight companies of Mechanized Services in Ahvaz city have been examined from their effect point of view in quantitative development of mechanization as well as resolving the problem of providing apicultural machinery (the first aim for these companies establishment), Their effect of making a balance in rental rate of the machinery (the second aim of establishment), and also the effect of these companies for extension of new and suitable technology (the third aim of establishment) as a field study. This study shows that existence these companies in order to promotion of suitable technology as well as increasing of various actions mechanization degree that at present these degrees are very low (5% - 10%), is very necessary. But because of rawness, management feebleness as well as lack of vocational outlook towards the companies by their members, these companies have got a lower level in quantitative output against private organisations providing machinery services in this region. In other words, in portion of facilities they posses, their activity have been feeble during their first aim evaluation. In addition, since the support and encouragement shortage after being established as well as observation shortcomings on these companies, in the second aim of their establishment they have been useless in practice. Of course, in their third aim evaluation, since the existence of WHEAT PIVOTAL PLAN in the reigion, and propagating and inciting by this plan, these companies have had a fairly proper output. However, appreciating these companies as well as increasing their quantity in order to extend an appropriate and unconventional technology is recommended. Moreover, consideration to educational programs as well as increasing the supporting and encouraging activates besides as effective observation over them must be planned.

To determine the optimal planting densities and evaluate the yield possibility of com cultivar under mix-cropping system in Dezful region, a factorial design based on Randomized Complete Blocks Design with four replications was carried out in 1999 at Dezful. Four planting densities including of 65000, 75000, 85000 and 95000 plants/ha, in different combination with the pure stands of two hybrid (SC704 and SC711) along with three mixed cropping ratios [including of 3(SC704):1(SC711), 2(SC704):2(SC711) and 1(SC704):3(SC711)] comprised the twenty experimental treatments. Data collected were analysed to determine the optimal cultivar mix-cropping ratio by using both agronomical and computational indices and reciprocal yield model.Results showed that intercropping of com hybrids and increased SC711 in mix systems caused the reduction in tassel and silk appearance intervals by 5.97 days the 1(SC704):3(SC711) mix ratio. an increase in leaf angle and horizontal arrangement of leaves in canopy. The grain yield of pure cultivation of SC704 and 3(SC704):1(SC711) mixed ratio were amounted to be maximum (7860 and 7842 kg/ha, respectively) and with the increasing of SC711 portions, grain yield decreased.A agronomical and computational indices measured showed that 1(SC704):3(SC711) combination of hybrids with 85000 plants/ha due to obtaining of LER=1.214, 21.5% increase in relative yield total (RYT), highest competitively, least reduction in per plant yield and maximum per plant yield proved it to be the best combination. Relative competition ability (RCA) and nich differentiation index (NDI) estimates indicated that intra-competition of SC711 as compared to its inter-competitionwas higher than SC704 and 8% nich differentiation between hybrids showed that mixed-cropping system yielded more than their pure cultivation.

Sugarcane is a sensitive crop to soil salinity and therefore, salt-affected soils like southern Khozestan soils must be reclaimed before planting of this crop. Traditional method for reclamation of such salt-affected soils is leaching with local river water (e.g. Karoun) that always gives satisfactory results. Sometimes after leaching of salts, brown spots (with high salinity and sodality) appeared on the soil surface which limits crop growth. The aim of this research was to investigate the possibility of different leaching treatment to reclaim such salt-affected soils using a physical model. In this physical model first, hydraulic conductivity of the soil was increased by restructuring the soil and then the soil was leached with water of different salinities to stabilize the soil structure during leaching. The treatments were: leaching with Karoun water (EC=2dSm-1), leaching with saline water (EC=10dSm-1 of saturating the soil samples and then leaching with Karoun water) and leaching with Karoun water plus 5 Mgha-1 gypsum. During leaching, electrical conductivity (EC), sodium absorption ratio (SAR) of percolating water and soil hydraulic conductivity were measured. The experimental design was split plot with three replicates.Results indicated that hydraulic conductivity of the soil of brown spots in comparison with the other area was significantly different (p<0.01). This might be due to the differences in soil bulk density. However, leaching the soil of brown spots using Karoun river water was successfully completed in the physical model. Therefore, the results indicated that reclamation of such soils is possible by increasing the hydraulic conductivity and leaching with Karoun river water. In the field, however, such process could be limited because of the low hydraulic conductivity and poor drainage conditions of soils. By sub soiling the soil, the hydraulic conductivity could be increased and the brown spots reclaimed if enough drainage conditions are provided.

Soil salt leaching studies were carried out in a 20-hectare experimental field during summer 1997 in Mollasany's Region to be compared with the results of double ring infiltrometers (25cm inside and 50cm outside diameter) which have been commonly used by consulting engineers to determine the appropriate depth of leaching water for irrigation and reclamation projects. The experimental field bas 16 subsurface corrugated-PVC-drain lines and earthen open drain collectors. The drain spacing was 40.60 and 80m apart soil texture was silty clay and silty clay loam. During experiment before and after Jeaching Soil analysis leaching water quality and quantity were measured and recorded. The resulting egression equations were compared with the Mollasany's Soil Series and North Ahvaz (East and West) compound desalinization and detoxification equations. Which were derived from the double ring infiltrometers data. The results showed that for initial salt leaching 75% excess salts from unit depth of soil profiled 0.20.0.50 and 0.98 and for removal of 85% excess salts 0.6. 1.06 and 1.34 unit depth of leaching water were computed for Mollasani Soil Series. North Ahwaz and experimental field equations.

In this work the ecology of rust fungi in Iran is discussed on the basis of observations made in the field and relations between rusts and their hosts. The distribution and occurrence of the genera of rust fungi on the various Biotic provinces of Iran were studied. Some information regarding rust flora of halophytic plants in Iran is presented. Occurrence of some Iranian rust fungi in different habitats was studied and [actors affecting the occurrence of rusts in Iran are discussed. The Iranian rusts are classified to montane rusts, hygrophilous rusts, drought resistant rusts, tolerant to the lower temperatures rusts and thermophilic rusts, on the basis of factors determining their occurrence in the different habitats. Some examples of stenotopic and eurytopic rust species in Iran are presented. The phenological rhythm of Tranzschelia discolor in Caspan biotic province was studied. Variations in the phenological rhythm have been observed between the populations of this species. The distance between the primary and secondary hosts in heteroecious rust species viz., Uromyces dactylidis, Puccinia recondita s.l. and P. coronata was studied. The distance between the primary and secondary hosts was short in U dactylidis and P. recondita, while in P. coronata close vicinity of the primary and secondary hosts was not necessary for abundant infection. Some examples of collateral host Plants of rust fungi in Iran are recorded. The joint growth of Uromyces flectens and prasitic hyphomycete, Polythrinicum trifolii on the leaves of Trifolium sp. is recorded.