پژوهش در علوم کشاورزی (JOURNAL OF RESEARCH IN AGRICULTURAL SCIENCE)
سال:1384 | دوره:1 | شماره:1 |تعداد مقالات:12

Sesame (Sesamum indicum L.) is one of the oldest oil crops and is widely cultivated in Asia and Africa. Characterization and quantification of genetic diversity has long been a major goal in evolutionary biology. Information on the genetic diversity within and among closely related crop varieties is essential for a rational use of genetic resources. The analysis of genetic variation within and among elite breeding materials is of fundamental interest to plant breeders. It contributes to monitoring of germplasm and can also be used to predict potential genetic gains. To determine the level of diversity in relation to geographical origins and morphological characteristics, a total of 60 accessions have been collected from different parts of the India were analyzed using statistical techniques for thirteen quantitative and four qualitative parameters using D2 analysis. Number of seeds per capsule contributed highest towards the divergence. The distribution pattern of genotypes in different clusters indicated that genetic divergence was not related to geographical differentiation.

In order to study the genetic variation and relationships among traits, an experiment was carried out on 15 genotypes of Carthamus tinctorius L. under field conditions in randomized complete block design with 4 replications in Payam Noor University, Zavareh. Agro-morphological characters, including seed yield/plant, biological yield, number of capitula per plant, number of seed per capitula, 1000- grain weight, number of secondary branches, capitula weight, oil yield and harvest index were measured. Results of the analysis of variance showed significant differences among genotypes for all studied traits (p£0.01). High values of phenotypic and genotypic coefficients of variation were obtained for most traits, indicating high variability in the traits under study. Seed yield/plant had significant high and positive correlations with capitula number per plant, seed number per capitula, biological yield and oil yield. Principal component analysis showed three factors that justified 94.33% of the total variation. Cluster analysis grouped the 15 genotypes within 4 clusters, each of which having 9, 2, 1 and 3 genotypes. The clustering pattern of the genotypes revealed that geographic diversity was not related to agronomic diversity. These results could be useful in choosing genotypes for intercrossing to develop improved cultivars.

Effects of soil and atmosphere pollution on some heavy metals (Fe, Zn, Pb, Cu, Mn and Cd) concentration in Acacia (Robinia psudo acacia L.) leaves were studied in the city of Isfahan, Iran. Samples were collected from four sampling sites representing area of high traffic density, light traffic area near the city, industrial area and one village far from pollution source as a control. Samples were collected in two seasons (June and September) in 2010 for chemical analysis. Based on the results, the collection time of leaf sampling did not showed any significant effects on concentration of the measured heavy metals in leaf samples. Chemical analyses of soil samples at depth of 0-10cm showed that concentration of these elements in most cases were lower than the maximum recommended levels. Lower concentrations of all measured heavy metals were found in washed leaves in comparing with unwashed ones. In spite of that, there was no significant correlation between the concentrations of heavy metals in washed leaves and in soil samples. Results of this investigation showed that the industry and traffic were the main source of air pollution in Isfahan, and acacia tree is a dependable biomonitor for air and soil pollution investigations.

One of the effective managing methods for slugs control is cultural method. A field study on the effect of different irrigation times on slug (Agriolimax agrestis) (Stylommatophora: Limacidae) damage in lettuce plants was carried out in the Varamin region in 2009. Treatments consisted of irrigation at various times: 1- irrigation in the morning, 2-irrigation after sunset 3-irrigation after sunset with Fericol bait (5gr/m²) and 4-irrigation after sunset with Methaldehyde bait (2.5gr/m²). The experiment conducted in a randomized complete block design with four replications. Each replicate consisted of three rows of 3 m length and 50 cm width and with in row plant spacing of 25 cm with a total of 36 plants /plot. The results indicated that maximum damages (based on the feeding of leaves) and minimum lettuce yield obtained for irrigation after sunset treatment with 52.82±3.4 percent of damaged plants with a lettuce yield 20.12 ton per hectare. Minimum damages with maximum yield found with treatment 4 with 10.53±2.8 percent damages with lettuce yield of 39.3 ton per hectare.Treatments 1 and 3 were with 10.92±2.7 and 10.71±2.3 percent damage and lettuce yield of 39.01 and 39.17 ton/ha respectively. There was no significant differences between the lettuce yields in the treatments 1, 3 and 4 at level of 5% (p>0.05) and were placed in group A. Also, it seems that changing irrigation times (treatment 1) is one of useful strategies in IPM method for controlling and reducing slug damage to lettuce plants which it has lettuce yield near to treatments 3 and 4.

A study was carried out to investigate the effect of chemical treatments and sucrose on vase life of three new rose cultivars, 'Bouing', 'Creamly' and 'Sena'. Treatments were included distilled water (control), 10 g l-1 sucrose, 10 g l-1 sucrose+100 mg l-1 citric acid, 10 g L-1 sucrose+100 mg l-1 aluminium sulphate, 10 g l-1 sucrose+0.5 mM silver thiosulphate for 2 h. Results showed that the best treatment for 'Sena' was silver thiosulphate+sucrose that increased fresh weight, water uptake, flower diameter and flower vase life. On the other hand, this treatment caused petal burning in 'Creamly' in spite of its other improved traits. Best treatment for other cultivars was citric acid+ sucrose that had significant effect on all investigated factors. Aluminium sulphate just had a positive effect on 'Sena'. This treatment did not have positive effect in 'Creamly' and even decreased vase life of ‘Bouing’ in comparison with control.

In order to study the effect of planting date, depth of sowing and planting density on yield and yield components of potato (Solanum tuberosum L.), an experiment was carried out in Shahrood (Iran) in 2009-2010. The first treatment was three planting date (11, 21 and 31 May 2010), the second treatment was planting density including 8 and16 plants per square meter and the third treatment was depth of sowing (10, 20 and 30 cm). For studying crop growth physiology, sampling was done every 15 days. Total dry weight along with leaf, stem and tuber weights were determined to demonstrate dry matter accumulation trend. Final yield and yield components were measured at the end of growth season. Other traits included plant height, number of tubers in square meter, number of tubers in plant, average tuber weight, and protein yield. Results showed that tuber yield was affected by experimental factors. Planting date, depth of sowing and planting density significantly affected tuber yield. Planting date, depth of sowing and planting density significantly affected all traits except protein percentage which was not significantly influenced by plant density factor. Planting date (11 May 2010) and plant density (8 plants/m2) and depth of sowing (20 cm) treatment produced 31.800 ton/ha and was maximum yield in comparison to other treatments.

Expansion and economical importance of yield reduction due to iron deficiency chlorosis in the world has attracted many researchers attention. Different materials, such as iron sulfate, acidified remediation, wastes, by-products of industries, iron chelate and organic compounds, have been tested to correct iron chlorosis. This experiment studied effect of applying an iron fertilizer for corn (SC 704) consisting sulfur and Thiobacillus bacteria. Experiment was carried out in greenhouse in factorial with complete of randomized design in four replications. The first factor was two kinds of irrigation water, w1=irrigation with ordinary water of soil and water research station of Karaj and w2=irrigation with acidified water of station with pH of 5-5.2 (acidified with sulfuric acid). The second factor was seven iron fertilizer treatments, T1=Control (without iron fertilizer), T2=Iron sequestrine 138 (10 mg. kg-1), T3=Iron sulfate (110 mg.kg-1), T4=Iron oxide powder of iron ore (220 mg.kg-1), T5=T4+sulfur (250 mg.kg-1 powdered sulfur) +Thiobacillus inoculant (104 cell.gr soil -1), T6=T5+organic matter, T7=T3+organic matter. Nitrogen, potassium, triple superphosphate, Mn, Zn, Cu sulfates and acid boric was used 200, 85, 90, 10, 5, 10 and 5 mg. kg-1, respectively. In the end of experiment, Dry shoot and root weight, iron uptake, chlorophyll Index (SPAD 502) and Fv/Fm were measured. Based on results, acidified irrigation water had significant effect on shoot dry weight and P and Fe uptake at five percent probability level, but had no significant effect on chlorophyll index. Effects of different fertilizer treatments on dry weight, P and Fe uptake and chlorophyll index, against Fv/Fm, were significant on five percent level. T6 and T7 produced highest shoot dry weight and T2 produced the lowest. The highest amount of P and Fe uptake was belonging to T7 and the lowest was belonging to T2. The highest amount of chlorophyll index was belonging to T6. Between treatments there was no significant difference on Fv/Fm factor.