Journal of Water and Soil Science
Year:2007 | Volume:10 | Issue:4 (B)|Papers Count:27

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 chlormequatchloride0, 1500,and 3000 mglliteron 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.

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 spike lets 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 different 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 120 Kg/ha N.

This 3tudy was carried out to evaluate the yield potential and other agronomic traits of nine genotypes of flax at two different spring planting dates: April 4 and May 5, 2003 and 2004, using a randomized complete block design with three replications at the Research Farm of Shahrekord University. The results showed that the effects of planting date and genotypes were significant on all of the traits, and the genotypes had a great genetic variation. On average, the range of number of seedlings/m2,maturity, plant height, yield/plant, seed yield and seed oil content of genotypes were 306 to 464,93.3 to 105.1 days, 28.8 to 58.2cm, 0.274 to 0.569g, 995 to 1423 kg/ha and 32.88 to 34.83%, respectively. The lowest mean of plant height and the highest mean of seed yield/ha were observed for Kordestan local population. Late planting significantly decreased the number of seedlings/m2, days to maturity, plant height, yield/plant and seed yield/ha, while this increased seed oil content. Average of seed yield/plant and seed yield/ha in the first and second planting dates were, respectively 0.506 and 0.414g, and 1598 and 811 kg/ha. Significant interaction of genotype by planting date for seed yield/ha and seed oil content was mostly due to the variation in the reduction of seed yield and increasing or decreasing of seed oil content in some genotypes in the second planting date. The genotypes had a variation of 1358 to 1784 and 632 to 1088 kg/ha for seed yield in the first and second planting dates, respectively. The local population of Kordestan bad the highest mean of seed yield in both years. The results of regression analysis and also the correlation coefficients showed that the number of seedlings/m2 and seed yield/plant bad the most contribution to the seed yield variation. The trait of number of seeds/capsule and number of capsules/plant were the main and most important yield components affected on seed yield/plant and due to can be used as selection criteria in selection programs to improve seed yield.

In order to evaluate grain yield potential and study dry matter remobilization to seed, 8 commercial bread wheat cultivars were examined in two separate experiments, using randomized complete block design with 4 replications in 2003. There were significant differences for most traits in normal and drought conditions. Sarday variety had the least grain yield in the two environments. There was considerable variation between genotypes for independent parameters of dry matter remobilization to different plant parts in the two environments. Factor analysis showed that seven factors accounted for 100 % of the data total variance in normal and drought conditions. Factor analysis also showed that the effective traits to components grain yield, height and phonological traits were important for the selection of appropriate genotypes. Calculation of drought resistance indices showed that four indices including mean productivity, geometric mean productivity, harmonic index, stress tolerance index were more effective than other indices for the selection of drought tolerant genotypes.

An experiment was conducted to investigate the genetic diversity in the cultivars and F1 hybrids of durum wheat, using agronomic and morphological traits. Evaluation of consistency between choosing parents of crosses based on morphological and agronomic observations and genetic distance obtained from cluster analysis were objectives of this study. Fourty- two genotypes were evaluated using a randomized complete block design with three replications in 2003. Agronomic characteristics comprised days to 50% flowering, days to 50% pollination, days to maturity, plant height (cm), spike length (cm), grain weight per spike (gr), number of grain per spike, number of spike per m2, grain yield (t/ha), biological yield (t/ha), 1000 grain weight, test weight (gr/L) and harvest index were measured in the studied genotypes. The results of analysis of variance showed significant differences among genotypes for all the studied traits. The results also revealed that grain yield had the highest coefficient of variation (CV= 21.6%), followed by spikes per m2 (CV= 20%) and number of grains per spike (CV= 18.9%). Lowest coefficient of variation was observed in days to maturity, days to 50% pollination and days to 50% flowering. Moreover, correlation analysis indicated that grain yield correlated with harvest index, biological yield, grain per spike and grain weight per spike. Cluster analysis of genotypes based on agronomic traits defined desirable clusters. These clusters have desirable characteristics and are beneficial for breeding objectives. Results of evaluation of consistency between choosing parents based on observation and those of cluster analysis showed varing degrees of consistency in 12 conducted crosses, ranging from highly similar parents in Eupoda6xChahba88 to relatively distinct parents in PI40100xPI40099 cross.

The effect of Rathayibacter tritici on the movement of Anguina tritid larva and nematode function as vector of ear rot bacterium was conducted in the laboratory (Agarose plates) and greenhouse conditions. The results showed that the contact of nematode larva with high concentration of bacterium or long duration of nematode-bacteria contact can decrease the movement and the efficiency of nematode function as the vector of the disease, and in some cases it resulted in the mortality of the nematode. No differences were detected in the mobility of larva in the concentrations less than 102 CFU and less than 0.5 hour of nematode-bacteria contact times and their controls (exposed to water alone).Movement of the nematodes appeared to be random under these conditions. It can be concluded that Rathayibacter tritid did not act as an attractant to Anguina tritid larva. These results suggest that the attachment of a large number of bacteria to nematode (as an essential vector of the bacterium) would induce nematode weakness and mortality. So it is possible that ear rot bacterium can parasite ear cockle nematode, or the nematode is a host for this bacterium.

Seven species of aphids belonging to the family Aphididae in six genera were collected and identified in wheat and barely fields in Sistan region (Miankangi, Shahraki-Narooi, Shibab and Markazi) during 1999-2000. Among them, Schizaphis graminum (Wheat green aphid) was the dominant species with an abundance of about 85.4% in the area. The seasonal population changes of Schizaphis graminum were studied simultaneously in the fields of Sistan region (Zahak research station and its surrounding fields). The research was conducted in half a hectar of each farm. Thirty leaves from each field at weekly interval were randomly picked up and the aphids were collected and identified at the species level. The Schizaphis graminum had a peak of activity in the second half of March to April at the temperature and R.H. ranges of between 22-28°C and %45-65R.H. respectively. The control conditions study (Incubator with 25±2°C and %75±5 R.H.) indicated that the Schizaphis graminum had a life cycle of 5-7 days and adult female longevity was 20-31 days. Rearing study also revealed that this species had ability to reproduce up to 18-98 nymphs in the laboratory condition (Cultural roam with 20-25°C and 55±5 R.H.) and an apterous female gave birth to 22-93 nymphs in her life. Samplings for recognition of predators and parasitoids were also done at 3-day intervals. Natural enemies in the fields during the two years were identified as consisting of six coccinellid (Col: Coccinellidae), ten syrphid (Dip: Syrphidae) and two chrysopid species (Neu: Chrysopidae). Also in Hymenoptera, five parasitoids (Hym: Aphidiidae) were determined.

Ascochyta blight caused by Ascochyta rabiei is one of the major diseases of chickpea (Cicer arientinum) in Iran. Many phytopathogenic microorganisms, incuding A .rabiei, attack their host plant by secreting pectic enzymes including polygalacturonase (PG) which causes modification of cell-wall structure, increasing accessibility of cell-wall components for degradation by other enzymes. Polygalacturonase is the major factor in the initiation of Ascochyta blight disease, therefore in this study; the enzyme was purified from a virulent isolate of A.rabiei (lK06). Fungi were cultured in PZ medium; culture media were harvested and after dialysis used for purification. Purification was achieved by Carboxy Methyl Sepharose Fast Flow ion exchange column equilibrated to pH= 5.5. Zero to one molar NaCl gradient was used for elution of the proteins from the column. Determination of protein content and enzyme activity of each fraction showed that PG was eluted from the column in 0.3 to 0.4 M salt. The purity of the protein and the MW of the enzyme were determined using SDS-PAGE technique. The MW was found to be around 27 KDa. The activity of the purified protein was also evaluated using polyacrylamide gel containing pectin as substrate (zymogram gel). Optimum pH for the purified enzyme was 7.5.

The cottony Cushion Scale, Icerya purchasi Mask., is a polyphagous, cosmopolitan and destructive pest that infests more than 200 plant species apart from citrus. Laboratory studies were carried out on the orange at three temperatures, 17±1, 27±1 and 40±1°C; 65±5% RH and 14±10 (L:D). The duration of nymphal stages, female longevity and the life cycle at 17±1°C were 85.8±3.83, 74.9±3.53 and 173.6±7.63 days and at 27±1°C were 62.6±4.40, 72.6±4.59 and 144.1±9.26 days, respectively. The duration of pupal stage and the life cycle of male at 27±1°C were 16.1±0.78 and 59.4±1.30 days, respectively. Field studies on the pest were conducted from July 2003 to September 2004 at Sharafabad region of Dezfu1. At 10-days intervals, five randomly selected orange trees in citrus orchards (3ha) were sampled by taking 75 twigs, 15cm in length, at random. Number of eggs, nymphal stages and adults were recorded. From these observations I. purchasi had three generations in a year that were recorded as spring, summer and autumn-winter generation for I. purchasi. The autumn-winter generation developed in 6 months. I. purchasi over winters, as different developmental stages on different host plants with the 2nd nymphal stage was more abundant. Apart from different citrus cultivars, altogether 41 species of 22 different families of plants were recorded as the host plants of this scale in Khuzestan province.

To carry out this study, total DNA was extracted from eggs and from second stage juveniles of several populations of Meloidogyne javanica and Meloidogyne incognita, using phenol/chloroform method. Following mgextraction, DNA was electrophoreses on 1% agarose gel to determine its quality and quantity. A specific primer pair (C2F3/1108; 23 and 20 nucleotides, respectively) was used to discriminate M.javanica from M. incognita populations using polymerase chain reaction (PCR). Primer annealing sites were located in the 3 portion of mitochondrial gene encoding cytochrome oxidase subunit II (COII) and in the 16S rRNA gene. Following PCR amplification, electrophoresis of amplified DNA showed 1.7 kb fragment in populations of both species. Digestion of 1.7 kb amplified product with Hinfl restriction endonuclease resulted in the generation of two DNA fragments of 0.7 and 1.0 kb in M. javanica and three DNA fragments of 0.3, 0.4 and 1.0 kb in M. incognita. There were no differences in the digestion patterns among various populations of each species examined.

Canola (Brassica napus) is one of the important oil seed crops cultivated in many parts of Iran. One of the main problems cif seed productions of canola is pollination and fertilization of flowers. Insects are the major pollinators. In order to study the fauna of insect pollinators of 3 cultivars of canola including Talaye, Okapi and S.L.M. and the difference between the attractiveness of these cultivars to insects during the flowering period, insects were collected by sweeping net and identified. Their abundance was determined at different periods of time during a day. Results showed that insect pollinators belonged to five orders and 18 families. The most abundant pollinators were Hymenopterous insects specially honey bees (Apis mellifera) which were about 50%. Irrespective of Apis mellifera, the most abundant insects captured belonged to Diptera. Three Dipterous insects, Bibio hortulanus, Metasyrphus corollae and Platypalpus sp. were collected and identified. During the flowering period (March to mid April) in Isfahan, honey bees were more abundant in the warmer hours of the day, mostly noon and afternoon, but were less active in the early hours of the day, morning, because of cold weather and low nectar production. Honey bees were more active than other pollinators on Talaye at 9 a.m. and on Okapi at mid-day, noon, and during afternoon. Results also showed that insect pollinators could increase seed yield by 53%.

A dairy chocolate-flavored beverage was prepared using 55 % whey permeate and 45% whole milk. The beverage was sweetened by 3% date extract and 3% sugar. The blend was mixed with 0.7% cacao powder, 0.2 % caraginan, 0.15% vanilla, 3% skim milk powder, and 3% pasteurized cream (30%fat). Control sample was prepared by 100% whole milk without skim milk powder and cream. Both samples were heated up to 50°C, blended by a mixer for 2 minutes, then pasteurized at 85°C for 30 seconds and immediately cooled down to room temperature. Stability, pH, protein, total solids, fat and acceptability of the beverage and control samples were then evaluated. The new beverage had high acceptability.

Qualitative indices including moisture content (M), total lipid (TL), peroxide value (PV), free fatty acid (FFA), heme iron (HI), TEA, neutral lipid (NL) and phospholipid (PL) content were investigated on anchovy fish immediately after harvesting and during frozen storage at -18 and -30°C up to 8 months (2, 4, 6, 8). Profile of their fatty acid and any possible changes were also determined. Statistical analysis of the results showed significant increase of PV, FFA, NL and significant decrease of TL, HT, PL, poly unsaturated fatty acid (PUFA) and omega-3 at each temperature rate in relation to time of storage. Based on the statistical analysis, storing of the sample at -30°C had higher lipids quality. The principal component analysis (PCA) showed that HI can be grouped with important quality indices such as PUFA and omega-3.

An experiment was carried out to investigate the effects of different levels of energy (2700, 2900 and 3100 kcal/kg) and protein (13, 14.5 and 16 %) on laying performance of Fars native hens during the first phase of production. Two hundred and sixteen 25-week-old native pullets were put into fifty four groups of similar live weight (994±169 gr) of four chickens, which were randomly allocated tQ nine experimental diets. Each treatment was replicated six times in factorial CRD design (3x3). At each level of energy, three diets were formulated to contain three levels of protein (16, 14.5 and 13%). The diets were fed ad libitum for a period of 20 weeks (week 25-45). The treatments 1 with 3100 kcal/kg ME and 16% protein and 3 with3100 kcal/kg ME and 13% protein had less daily feed consumption than treatment 7 with 2700 kcal/kg ME and 16%protein (90.50 and 87.30 vs 101.20 gr respectively, P<0.05). The effect of energy levels on daily feed and energy consumption and feed conversion ratio was significant (P< 0.05). Feed conversion ratio for energy level of 3100 kcal/kg was significantly different from 2700 kcal/kg (2.85 vs 3.08 respectively). The effect of protein levels on uric acid content of excreta and daily protein consumption was significant (p< 0.05) and protein level of 16% was significantly differed from protein level of 13% (11.40 vs 10.50 gr respectively). The results of this experiment showed that it is preferable to use the energy level of 2700 kcal/kg and protein level of 13%during the first phase of production of Fars native hens.

In order to assess and determine amino acids profile and their availability in different sorghum grain (SG) varieties, three SG varieties including low tannin (0.09%, LTS), medium tannin (0.19%, MTS) and high tannin (0.37%, HTS) were grown at the same location. The grains were analysed for their proximate analyses, tannin and amino acids. True amino acid availability (TAAA) was obtained by Sibbald's method using ceacectomized single comb leghom cockerels. The results showed that methionine and cystine were the first and the second limiting amino acids, respectively in LTS and MTS. But in HTS, lysine (0.166%) was the first and methionine (0.176%) was the second limiting amino acid. Methionine content was 0.114%, 0.182% and 0.176% for LTS, MTS and HTS, respectively. Although, crude protein was lower in HTS (10%) than the other SG, but histidine, methionine and isoleucine were higher for HTS in comparison to LTS and MTS. TAAA decreased when tannin content increased and all amino acids had a lower availability in HTS than LTS and MTS (P<0.05). Methionine in HTS and LTS and glutamic acid in MTS had the highest availability. The availability of proline was most affected by tannin, and its availability was 91.55% for LTS, 84.82% for MTS and 22.82% for HTS (P<0.05).

To study the effects of terbutaline (a beta adrenergic agonist) on performance of broiler chickens, 21 d-old male and female Cobb broiler chicks (n=300) were randomly assigned to one of five dietary treatments containing 0 (control), 5, 10, 15 and 20 mg terbutaline per kg diet. The feed conversion ratio (FCR), feed intake and body weight gain were measured after 3 weeks. At 42-d age, six males and six females were randomly selected from each treatment and their live weight and weights of carcass, breast, breast muscle, drumsticks, drumstick muscle and abdominal fat were determined. Terbutaline didn't affect daily weight gain, but FCR of male chicks was reduced for 5 and 10 mg/kg terbutaline treatments compared with the control group (p<0.05). Carcass weight and weight of drumsticks, drumstick muscle, breast, breast muscle and ratio of breast to live weight of female chicks receiving 5 mg/kg terbutaline were higher than for other treatments (p<0.05). In male chicks, the live weight and weight of carcass, ratio of carcass to live weight, drumsticks and drumstick muscle at 5 mg/kg terbutaline treatment were higher than for other treatments (p<0.05). This experiment also showed that the addition of 5 mg terbotaline per kg diet during growing period improved FCR and ratio of carcass to live weight of male chicks, increased the ratio of breast to live weight of female chicks, and increased the carcass weight of male and female Cobb chicks.

Genetic variation within and between five Iranian sheep populations including Sanjabi (SAN), Kordi Kordistan (KKO), Kordi Khorasan (KKH), Menraban (MEH) and Moghani (MOG) was assessed using six microsatellite markers (McMA2, McMA26, MAF64, OarAE64, OarCP26 and OarFCB304). The PCR reactions were successfully perfomed with all primers except OarAE64. All locus-population combinations were at Hardy-Weinberg equilibrium except McMA2 in MOG population (P<0.005). Polymorphism criteria showed that the five studied loci were polymorphic in all populations. The lowest DA genetic distance (0.234) was observed between KKH and KKO and the highest (0.388) between SAN and MOG populations. The dendrograms based on DA distances were drawn using unweighted pair-group method using an arithmetic average (UPGMA) and neighbor-joining (NJ) method. KKO, KKH and SAN were grouped together at one cluster and MEH and MOG at another by both methods. The average expected heterozygosity for each populations (as interoperation variation) ranged from 0.744 to 0.847 for KKH and MEH, respectively. The estimated time of divergence for two Kordi populations (KKO and KKH) was 445 years that complies with mstorical evidences. The findings of this research confirmed that microsatellite variation could be a useful tool for screening of investigating biodiversity among domestic animals.

This paper investigates the effects of wheat production risk and other socio-economic factors on the probability of adopting new seed technologies. Also, the effects of production inputs and production conditions are examined on wheat production yield and risk. Moreover, the relative risk of new seed varieties will be examined under different scenarios. To carry out the study, farm-level data was collected from a sample of 187 wheat farms located in Fars province, and selected by multi stage random sampling method during the years 2001 and 2002. A generalized stochastic production function by a three-stage estimation procedure was used to determine the influential factors on the production yield and risk. The results showed that yield uncertainty could not be sufficiently explained by the level of input use in the cultivation of both wheat varieties. The comparison of two wheat varieties cultivation indicated that in the absence of suitable production conditions, on the average, the cultivation of new wheat varieties ensures greater yield than traditional wheat varieties, but involves greater risk, as measured by yield variance. Accordingly, the farmers' risk aversion attitude could be a major factor inhibiting speedy diffusion of new wheat varieties, which besides having greater average yield than traditional wheat varieties, it has less production risk. The results indicated that the risk associated with seed has negative effect on the adoption of new seed technologies.

Phenology is the study of time and sequence of recurring stages in the life history of an organism. The occurrence fashions of the phenophases form different phenological behavior patterns. Despite the importance of phenology and wide applications of knowing phenophases, few studies have been done on the wooden species in Iran. The goals of this study are identification and designation of the phenophases occurring time and their successions, phenological behavior patterns and finally phenological patterns assay of 35 fruitful and fruitless woody species. in the northeast of Esfahan during 2003-2005. Leaves, flowers, fruits, buds, bark and color changes were observed weekly or every other week. Analysis of the obtained charts and tables shows that with respect to the environmental and climatic condition of the area, observed phenological behavior patterns are two- leaf, two-flower and two-fruit emergent patterns; two-flower peak patterns; three-fruit perpetuity patterns; and three leaf shed patterns. Finally, there are three comparative successions, six-flower and three-leaf phonological patterns. Based on the findings, blooming and leaf shed calendars were also achieved.

Stress tests are commonly applied in shrimp hatcheries to estimate the quality of postlarvae to be used during grow out. The highest larval survival rate during culture and in shrimp stress tests has been reported when specimens are offered a diet containing high levels of highly unsaturated fatty acids (HUFA). Also vitamin C has positive effect to resistance and survival of larvae. In this study in post larvae stage 1 in the salinity stress tests (10 and 20 ppt) the highest survival rate was observed in treatment 3 (56.667 % and 90.00%) which was enriched with highly unsaturated fatty acids and vitamin C. As for the second, treatment 2 (43.333 % and 76.667%) which was solely enriched with highly unsaturated fatty acids showed significant differences at a level of (P<0.05) with treatment 3. The difference between these two treatments and treatment 1 (larvae fed rotifers cultured on Chlorella sp) and control (larvae fed newly hatched Arternia nauplii) was also significant. No significant difference was observed in formalin stress test (100 ppm) in this stage between treatments 3 (86.667%) and 2 (80.00%) which shows the highest survival rate. But difference between them with treatment 1(60.00 %) which was unenriched and control (53.333%) was significant. Also, in post larvae stage 5 in the salinity stress tests (10 and 20 ppt) the highest survival rate was observed in treatment 3 (56.667 % and 83,333 %) and later treatment 2 (40.00 % and 70.00 %) which showed significant difference, In this stage, the survival rate the treatment control (60.00 % and 86.667%) and treatment 3 showed no significant difference but they showed significant differences with treatment 1 and 2 .The lowest survival rate was observed in treatment 1(26.667 % and 56.667%). And the highest survival rate was observed in formalin stress test (100 ppm) in this stage in treatments control, 3 and 2 (76.667%, 73.333 % and 70.00 %) among which there were no significant differences. However, the difference between these three treatments with treatment 1 (53.333 %) was significant.