JOURNAL OF AGRICULTURAL SCIENCE AND SUSTAINABLE PRODUCTION
Year:2004 | Volume:14 | Issue:3|Papers Count:12

In recent years, flood, control projects have been widely applied throughout the country. An important aspect in these projects are the labor and cost requirements. The priority of sub-basin is practically performed traditionally. In this research a mathematical method based on multicriterion decision making is proposed for the sub-basins priorities. Most of these methods automatically line up the selection and provide the result without incorporating the decision maker. The utility additive approach with greater flexibility has been considered in this study because it gives a greater importance to decision maker. This method through some steps using piecewise linear programming continuously asks for choice of the decision maker. Thus, in this study 19 sub-basins of the Kan River in the Northwest of Tehran were evaluated according to 50 years return period, flood, lag time and fatal-cost damage. The results indicate that in spite of high flood volume in some sub-basins, they have not been selected due to other criteria considerations.

A pot experiment was conducted for the study of the effects of NaCl salinity on the accumulation of some mineral and organic matters in two onion (Allium cepa L.) cultivars. A split plot design was arranged with three replications. Two onion cultivars (Ghermez Rey and Tarom Zanjan) were asseigned to main plots and five salinity levels (0, 25, 50, 75 and 100 mw. NaCl) to sub-plots. Plants were raised in the Hoagland nutrition solution. Total leaf chlorophyll, proline, total soluble sugars and Na, K, Ca, Cl, P and S were measured at the final leaf growth stage, These minerals were also measured at the final bulb growth stage. Results showed that total chlorophyll significantly decreased with increasing salinity levels, while proline increased specially in Ghermez Rey cv. Ghermez Rey seems to be more tolerant to salinity than Tarom Zanjan. In addition, the significant increase of Na and Cl accumulation in the leaf and bulb particularly at high salinity levels led to nutrient deficiency and ionic toxicity.

The effects of feeding on aphids by green lacewing (GLW) on it’s fertility and the length of different immature stages were studied by using three different aphid species, namely rosy apple aphids (Dysaphis plantaginea Pass.), green peach aphid (Myzus persicae), and locust aphid (Aphis cracivora). Adult green lacewings were collected from the field in Khalatpushan Research Station and fed on 10% sucrose solution. By collecting of green lacewing eggs, one generation of GLW was reared on green apple aphid. Eggs from their offspring were used in the experiments. The lacewing larvae were reared in common ice-cups at 25±1°C and 75±5 R.H. in, an incubator. Emerged adults were fed on an artificial diet containing sugar, water and yeast extracts (1:1:1 by weight) during ovipostion period. Differences between each of the larval instars and among prey species and also their intracpon were significant (p=1%). Duration of larval and pupal stages was the longest in rosy apple aphid/ feeders while that of the locust aphid feeders was the lowest. Also the fertility of three mentioned dietary groups was significantly different (p= 1%) and the highest fertility resulted in feeding on the green peach aphid. It was concluded that a suitable prey may increase the developmental rate and / or fertility of a predator. Results indicated that favorable prey decreases developmental time of predator and increases adult fertility as well as it’s prey consumptions rate.

In order to evaluate the effects of cultivar and planting density on yield and yield components of potato, an experiment was conducted during 1996 in Bostan Abad (46, 50 N, 37° 51’ E) located at 55km east of Tabriz, Iran. A factorial experiment based on randomized complete block design with three replications was used. Combination of five cultivars; Alpha, Draga, Cozima, Morene and Auola, with three planting densities; 50000, 62500 and 75000 plants per ha-1 (27, 22 and 18cm between plants on the row and 75 cm row spacing,. respectively) were used as experimental factors. The number of tubers per plant and per square meter, tuber diameter, mean tuber weight, tuber weight per plant and tuber yield were significantly affected by cultivars. Cozima had higher number of tuber per plant and per square meter, tuber diameter, mean tuber weight, tuber weight per plant and tuber yield (39.5 t ha-1) among the cultivars evaluated. All the traits under study were affected by plant density. Number of tuber per plant, tuber diameter, mean tuber weight, tuber weight per plant and dry matter percentage of tuber were decreased as plant density increased, but number of tuber per square meter increased significantly. The tuber yield increased by increasing the plant density from 50000 to 62500 and decreasod thereafter when the density was raised from 62500 to 75000. Tuber yield showed significant correlations with number of tuber per plant and per square meter and tuber weight per plant. On the basis of the result of this study, planting Cozima and Auola cultivars with 62500 plants per ha-1 in Bostan Abad, may be recommended.

During 2001-2003, a study was conducted to identify parasitoids of scale insects (Hom.: Coccoidea) in some provinces of Iran. Samples were taken from infested trees in different localities and kept in insect boxes under room conditions. Among the samples three species of encyrtids including Metaphycus claviger (Timberlake), Metaphycus pulvinariae (Howard) and Microterys nuticaudatus Xu were identified as parasitoids of Coccus hesperidum (L.) from Shiraz, Didesmococcus unifasciatus (Archangelskaya) from Shend Abad (Shabestar, East Azarbaijan), Parthenolecanium corni (Bouche) (Hom.: Coccidae) from Tehran and Aphytis hispanicus (Mercet) (Hym.: Aphelinidae), as parasitoid of Aulacaspis rosae (Bouche) (Horn.: Diaspididae) from Karaj, respectively. These four species are new records for Iranian fauna of Hymenoptera.

Five inbred lines of rapeseed (Brassica napus L.), Orakel, ACSNl, PF504588, PF704591 and Boanty, which were previously selected for variation in callus characteristics, were crossed to produce diallel progenies. The parents and their F1 hybrids were evallflted in a completely randomized design with four replications. In each experimental unit, 10 seeds were grown on MS (Murashig and Skoog) medium in petri dishes. Data were collected after five weeks on percent of callus indication, callus diameter, callus fresh weight and callus dry weight. The resulting data were analysed according to Griffin’s (1956) method 2 mixed model B. Analysis of variance revealed significant difference among genotypes for the above characters. General combining ability (GCA) was only significant for the percent of callus induction, while significant specific combining ability (SCA) were observed for all callus characteristics. Broad sense heritabilities were high; indicating that callus induction and growth in culture media is under genetic control. However, the narrow sense heritabilities were low; suggesting that dominance gene action was more important in the genetic control of the traits under study. Drakel was also characterized by higher estimate of GCA effects for all the characters studied. This genotype, therefore, seems to be a suitable genetic material for callus growth and induction. Among hybrids, Drakel × ACSNI and ACSNI × PF504588 showed higher means and SCA effects for callus fresh weight, dry weight and diameter. However, for percent of callus induction, higher means and SCA effects were observed for the crosses ACSNl × PF704591 and ACSNl × Boanty. This indicates that the genes encoding callus induction were different than those of callus growth. HI and H2 were higher than D, indicating that, the dominant component was larger than additive component. Epistasis was almost absent in all traits. Dominant alle1es caused high and recessive alleles caused low expression of callus induction and growth.

Effects of rainfall, simulated by two different methods and at two various rates, on the erosion from a loam soil were studied under both plowed and unplowed conditions. The study was conducted at East Azarbaijan Research Station Center (Khosrowshahr) by employing a factorial experiment based on randomized complete block design with four replications. Rainfall to the experimental plots were simulated by using a rainfall simulator with 100 and 200 mm/hr and a rotating sprinkler with 100 mm/hr. Amount of erosion was determined by conveying the runoff generated during 30 and 120 minutes to the pre-installed containers and then measuring its solid material contents. The results indicated that raising rainfall rate from 100 to 200 mm/hr almost doubled the amount of erosion under plowed soil surface condition; erosion from unplowed soil, where the surface left covered about 50% by the natural vegetation, was not significantly affected. Average amount of erosion during 30 minutes experiment was 18.7 tons/ha from plowed plots as compared to 4.0 tons/ha from the unplowed sites, irrespective to the kind and rates of the rainfall generated. Extending duration of rainfall to 120 min., when steady state infiltration rate was realised, increased erosion to 38.7 and 71.0 tons/ha with 100 and 200 mm/hr rate, respectively, under plowed condition. The corresponding figures were 7.2 and 11.8 tons/ha for undisturbed plots where the soil surface was about 50% covered by the natural vegetation and / or plant residues. Two methods of rainfall generation (simulator and sprinkler) did not produce significant effect on erosion. This implies that even though a small area of soil is depicted and goes under rain with rainfall simulator, however, the results may be applied to large areas or at large scales.

To study the effects of soil freezing on seeds of bread wheat genotypes and it's relation to growth habit and some agronomic characteristics, several experiments were carried-Out on 12 bread wheat genotypes using RCBD with 4 replications in Maragheh Dryland Agricultural Research Station under both laboratory and field conditions. Under field conditions several agronomic characters including: % winter survival, growth vigor, plant height, maximum tillers number, fertile tillers number, days to spike emergence, days to maturity, grain filling period and grain yield were measured. Under laboratory conditions, survival percentage of imbibed seeds after 60 days chilling (-3.5°C) and coleoptile length of seedlings after 15 days were recorded. The differences among genotypes for the % winter survival, growth vigor, coleoptile length, plant height, maximum tillers number, days to spike emergence, days to maturity, grain filling period and grain yield were significant (P≤0.05) but, genotypes did not have significant differences in soil freezing tolerance. The correlation between imbibed seed frost tolerance under laboratory condition with growth vigor and grain yield were positively significant but, it was negatively and significantly correlated with days to spike emergence. However, correlation of cold tolerance under field conditions with growth vigor and grain yield were positive. Correlation between growth habit with cold tolerance and grain yield were negatively significant (P≤0.01) under field conditions.

Seven wheat lines with different degrees of resistance to scab and their 21 F2 populationswere evaluated for fusarium head blight (FHB) resistance in a replicated field experiments at Golestan province, Iran, in 2001. After artificial inoculation, disease severity, disease incidence, area under disease progress curve (AUDPC) for disease incidence and disease severity and FHB index were measured. General combining ability (GCA) and specific combining ability (SCA) effects were calculated using Griffing’s method. Mean squares for GCA and SCA were significant for all characters. Both combining ability analyses and estimates of genetic components indicated that additive and nonadditive gene actions were involved in the genetic variability of the characters examined. However, additive effects appeared to be more important than dominance effects. Significant negative (desirable) GCA effects for Sumai#3 and Wangshui-bai and significant positive effects for Shiroodi, Falat and Tajan, were observed in relation to the traits under study. Significant negative (desirable) SCA effects were detected for all characters in two crosses (Falat x Sumai#3 and Shiroodi x Wangshui-bai). Broad-sense heritability estimates were high (0.81-0.89), whereas narrow-sense heritability estimates were almost intermediate (0.39-0.51) for the indices measured in the experiment. This indicates that selection for the FHB resistance should be possible using these indices specially the disease incidence which is an easy character to be measured in the field.

Sturgeon fishes (Acipenseridae)make a very important group in the fishes. These fishes have both high important and great food values due to their valuable Caviar product and white meat. In this investigation fatty acids from Persian sturgeon (Acipenser persicus) tissues - as a typical species in Iranian waters of Caspian Sea - and its variation during the cold storing, after extraction and methylation of the lipids from tissues of fish in fresh and frozen were, investigated. Identification of fatty acids was performed by gas chromatography. The results showed that the amounts of unsaturated fatty acids in & esh and frozen samples were 88.95 % and 79.63 %, respectively and amount of omega- 3 series were11.09%. in fresh tissues The amounts of oleic, linoleic, alpha-linolenic, icosapantanoic and docosahexanoic were 45.11 % , 3.59 % , 2.80 % , 4.75 % and 2.21 %, respectively and these are the most important polyunsaturated fatty acids. After twelve months of cold storing at -22-oC the amounts of some of the fatty acids such as oleic and alpha-linolenic decreased to 40.27 % and 1.65 %, respectively and arachidonic acid increased from 2.16 % to 4.24 % .These changes were significantat 5% level. In addition, the ratio of omega- 3 to omega- 6 fatty acids in the fresh tissues was 1.69.

In a greenhouse experiment, the effects of 0, 2.5 and 5 g/l NaCl salinity of irrigation water on Na, K, sucrose and fructose concentrations in the main stem leaves of three wheat cultivars were investigated during two weeks after anthesis. Inia, Sholeh and Tabasi were the three cultivars used, in a randomized complete block design as factorial treatments with three I replications. The results showed-that the concentration of sucrose in Tabasi increased and in Inia and Sholeh decreased under saline conditions, while no effect was observed regarding fructose concentration. The results of experiment showed that the Inia cultivar could not adjust its osmotic potential, whereas Sholeh and Tabasi made osmotic adjustment effectively under salinity. These two cultivars showed higher salinity resistance. A significant negative correlation was observed between leaf sodium and sucrose concentrations of the salt sensitive Inia cultivar; the correlation between potassium and sucrose was positively significant. There was no significant correlation between sucrose and these ions in Sholeh and Tabasi. Based on the results obtained, leaf sodium and potassium content alone may not give effective criteria for evaluation of salt tolerance in wheat. Leaf K concentrations along with the sucrose and fructose concentration seems to be more better or suitable criteria of salt tolerance in these wheat cultivars.