AGRICULTURAL RESEARCH
Year:2008 | Volume:8 | Issue:2|Papers Count:17

In this research, with sterilized conditions, sprouts and plantlets producing from meristem culture were divided segments 5-7 mm in length. Segments that were acquired from sprout and plantlets were transferred to erlene dishes containing MS and Nitch & Nitch medium. Each dish was considered as plot. Treatments were sat up as a factorial experiment based on randomized complete design, cultivars in two levels (Marfona, Agria) and two levels of media culture (MS and Nitch & Nitch). Treatments were applied in three replications. After four weeks plantlets that had some leaves and reached 4 to 5 cm in length were transferred to peat pot in the greenhouse. After 70 to 80 days, minitubers were harvested from these plantlets. Data of analysis variances determined that only cultivar had significant different at 5% a' level, but effect of culture medium and interaction effect (culture medium × cultivar) was not significantly different at 5% a' level. Both Agria and Marfona in two culture media had same situation in production of plantlets.

A total of 22268 records from 10 commercial silkworm lines reared in Iran Silkworm Research Center including Chinese lines of 32, 104, 152, 110 and 154 and Japanese lines of 31, 103, 107, 151 and 153 collected during 3 years in 4 rearing periods in spring and autumn were used for study of effect of inbreeding on economic traits. Two statistical models were used for analysis of the data. In the first model, inbreeding coefficient was considered as a covariate variable along with fixed effects of line, rearing year and season. In the second model, inbreeding effect considered as a classified fixed effect along with other mentioned fixed effects. All effects had highly significant effects (P<0.0001) on all traits. However, the non-significant effect of inbreeding on cocoon shell weight in the first model was an exception. Tukey-Kramer test was used for comparison of means. The means of different levels of each fixed effect were significantly (P<0.01) different for all traits. In the first model, partial regression coefficients on inbreeding were significant for cocoon weight (P< 0.0001) and cocoon shell percentage (P<0.01) and not-significant for cocoon shell weight. The results of this study showed that increasing of inbreeding significantly increases the cocoon weight and decreases the cocoon weight percentage, but its effect on cocoon shell weight is not significant. Regarding to the results of this study, it could be concluded that increasing of inbreeding has no noticeable effect on silk quantity. Therefore, increasing of inbreeding, at least, at the studied level of this population, is probably acceptable.

Aphidius matricariae Haliday (Hym., Aphidiidae) is one of the most important parasitoids of numerous aphids which is used in pest management programs. In this research, growth population parameters of A. matricariae were studied on Aphis fabae Scopoli (Hom., Aphididae) on four varieties of sugar beet (IC, PP8, Rasoul and Shirin). Experiments were carried out in a growth chamber with temperature of 25±1oC, 70±5 % RH and a photoperiod of 16L: 8D hours. Twenty newly emerged adult wasps were separately released in leaf cages containing 50 nymphs of aphids. After 24 hours parasitoids were placed in other leaf cages with the same conditions and was continued until the parasitoids death. The parasitized aphids on each variety were counted daily. The results were analyzed according to Jackknife method with SAS and MINITAB statistical softwares. In this research, the net reproductive rates (Ro) on IC, PP8, Rasoul and Shirin cultivars were 13.31, 18.18, 16.54 and 18.58 female/female/generation, intrinsic rate of increase (rm) were 0.360, 0.406, 0.401 and 0.408 female/female/day, mean generation time (Tc) were 7.18, 7.14, 6.99 and 7.17 days and doubling time (DT) were 1.92, 1.70, 1.73 and 1.67 days, respectively. The results showed that host plant varieties affect the growth population parameters of parasitoid.

Production of vermicompost from sewage sludge is one of the suitable methods for convert of this waste to organic fertilizer. In this study, effects of decomposition stage of sludge and bulking materials on growth of earthworms were investigated. Experimental design was split factorial in three replications. The main factor was the stage of sewage decomposition (raw sewage, digested sludge in digester, dewatered sludge in lagoons, and final dried sludge in lagoons), and kind of bulking materials (woodchips, tree leaves, and wheat straw) and mixing proportion of bulking materials to swage sludge (0, 15, 30, and 45 %, V/V) were as subordinate factors. After 5 months incubation of pots in controlled moisture and temperature conditions, numbers of worms, cocoons, wet body weight of worms, and concentration of nutrients and heavy metals in produced vermicompost were measured. Population of worms, their body weight and cocoon production were highest in the pots contain final dry sludge. The  growth and reproduction of earthworms were greater when wood chips used as bulking material for vermicompost production. There was no significant difference between wheat straw and tree leaves in this respect. The suitable mixing proportion of bulking material and sewage sludge was 30 % (V/V). Therefore, mixing of wood chips with dry sewage with the proportion of 30 % (V/V) for vermicompost production and use of this technique to improve the stability of sewage sludge produced in sewage treatment plants are recommended.

To do this study a factorial expriment based on a randomized compelet block design with three replications was carried out in research farm of Bahonar university, Kerman, in 2005. Drought stress was exerted by withholding water after stem extention stage (severe stress), after blossoming stage (moderat stress) and after flowering stage (mild stress). Irrigation in all growth stages was considered as control. The cultivars were Isfahan native, IL and LSP. Grain and biological yield, number of head per plant, oil percentage, specific leaf area and leaf relative water content were reduced significantly under drought stress. Leaf prolin concentration and grain protein percentage increased under stress condition. But drought stress did not significantly affect the number of grain per head, the 1000 grain weight and harvest index. Among the cultivars, the Isfahan native cultivar with the highest number of head per plant and number of grains per head, produced the highest yield. In all three cultivars, with increasing drought stress, the oil percentage decreased but leaf prolin concentration and grain protein percentage increased. The Isfahan native cultivar with the highest grain yield, oil percentage and grain protein percentage can be introduced as the best cultivar in this area. The leaf prolin concentration of this cultivar was higher than LSP while it had no significant difference with the IL cultivar. Therefore it is able to tackle with drought stress through osmotic adjustment and prolin accumulation. Totally, severe and medium stress had a significant negative effect on the measured characters. While in mild stress, no negative effect was observed. Thus, with a mild stress, it is possible to have the same yield and oil production as control and also a decline in production costs.

During 2005 – 2006 trails were conducted to evaluate the efficacy of Ridomil Gold for controlling pink rot of potato tubers during storage in a split plot design in Shahrood Agricultural Research Center. Three potato varieties namely: Santeh, Agria and Marphona were grown as main plots and 5 treatments: Ridomil applied at sowing time at the rate of 2.5 Kg/ton of seed as seed dressing (T1), One time ridomil applied at flowering at the rate of 2.5 kg/ha (T2), Two times ridomil applied at flowering at 28 days interval (T3) , Three times Maneb applied at flowering at 10 days intervals at the rate of 2 Kg/ha (T4) and control (T5 ) as sub plots. After 1, 2 and 3 months of storage, healthy tubers were artificially inoculated with the pathogen (P. cryptogea )and incubated at 25 - 27oC for 6 days. Tubers were then cut and left for 1 to 2 hours for pink color appearance and then fungal progress inside the tubers were measured. Statistical analysis of data showed significant differences between treatments in all tests (p= 0.1). Two times applications of Ridomil Gold at 28 days interval gave best result in inhibiting pathogen progress when tubers were artificially inoculated after one month of storage ( disease progress = 3.17 cm.). One time Ridomil Gold applications were less effective in all tests. Results showed that tuber resistance due to Ridomil Gold applications against pathogen was reduced by time so that the mean differences between fungal progress of T3 and T 5 after 1, 2 and three months were 2.35, 1.02 and 0.64 cm. respectively.

In order to find the best genotype and planting date of lentil (lens culinaris Medik.), the field experiment was conducted in Research farm of Agricultural faculty, Zabol University, in 2005-2006. The experiment was carried out in a split plot based on a randomized complete block (RCBD) with three replications, three planting dates (16 November, 6 and 26 December) as main plots and five genotypes, including (Zabol local lentil, Ziba, Gazvin local lentil, Lines 494 and 4605) as subplots. The result showed that grain yield, grain number per plant, pod number per plant, biological yield and harvest index were affected by planting dates. In comparison the hundred grain weight, branch number per plant, and plant height were not affected significantly. The values of all measured traits in first planting date were higher than the others, but by sowing delay, all measured traits showed a reducing trend. A high significant variation was observed in morphological traits among genotypes. The interactions of genotype with planting date on grain number per pad, pod number per plant and biological yield were significant. There was a significant negative correlation between hundred grain weight with other traits but not with biological yield. A higher correlation observed also was between pod number and grain number per plant and, between grain yield and biological yield. The lowest correlation was observed between hundred grain weight and biological yield. Zabol local lentil had the highest value for all traits in all planting dates, except for hundred grain weights, in comparison to other genotypes. So, it is recommended for growing in that region.

This research was carried out to assess the effects of aspect and landscape position on soil properties and the effect of these properties on almond yield and its quality in Saman area, Chaharmahal-va-Bakhtiari province. Samples from topsoil and subsoils (0-40 and 40-80 cm) were collected from three transects in northern aspect and three transects in southern aspect in five landscape positions. Almond samples were collected from two almond trees at each landscape position. At each aspect and on each landscape position, five soil profiles (in total, 10 soil profiles in both aspects) were studied along one transect. The results indicated that surface soil in northern aspect had higher levels of clay, organic matter, soil moisture, potassium and nitrogen in comparison with southern aspect (p<0.05). Yield, quality and some of vegetative properties of trees in northern aspect are higher than southern aspect. Yield decreases at down slope consisting of footslope and toeslope despite the better soil conditions. Decreasing the yield could be due to the frost-bite of almond tree in blossom time. Denser and colder air moves downward the toeslope harming almond blossoms. Differences in soil formation processes resulted in different soil classes according to Soil Taxonomy. In upslope positions, soils were classified as Inceptisols, whereas in down slope positions (footslope and toeslope) were mostly classified as Alfisols. Soil classification at family level could show the effect of soil properties on almond yield and quality. Due to better conditions of soils, northern aspects are recommended for planting almond trees in the region. Also in lower positions, planting frost-bite resistant and late-flowering cultivars, together with heating and sprinkler irrigation would increase almond yield.

The study was conducted to investigate the effect of male parent on embryo rescue of three seedless cultivars, Flame Seedless, Yaghooti and Askary. Pistils of female parents were emasculated and then were pollinated with pollen of Bidaneh Sefid (seedless), Dizmary or Mehdikhani (seeded) and self-pollinated as control. Forty days after full bloom, berries were harvested, ovules were excised and cultured on Nitsch and Nitsch medium containing 1 mM GA3, 10 mM IAA and 2 g/l activated charcoal. Germinated ovules were transferred to 1/2 MS medium. Male parent had significant effect on ovule blackening and ovule germination and no effect on callus formation, ovule growth or ovule collapse. The percentage of blackened ovules was increased when Bidaneh Sefid was used as male parent. However, it reduced the number of germinated ovules in compared with those from self-pollination. The effects of seeded male parents varied for different female parents. Compared with self-pollination, Dizmary increased ovule germination but Mehdikhani had no effect on ovule germination. It was found that embryo development and germination varied greatly with both female and male parent genotypes.

The effects of irrigation periods and fertilizer nitrogen rates on population of black bean aphid were studied in sugar beet fields of Isfahan University of Technology for two years. Experiments were carried out as splitplot in a complete randomized block design with four replications.Irrigation factor in three levels (100%, 75% and 50% plant water requierment in 2005 and irrigation after 70, 105 and 140 mm cumulative evaporation from class A pan in 2006) and nitrogen fertilizer in three levels (200, 150 and 100 kg/ha net nitrogen in both years) were allocated to main and subplots respectively. Pest population was assessed by weekly sampling. The highest mean population of black bean aphid was observed in 100% irrigation treatment in the first year and in irrigation after 70 mm evaporation treatment in the second year and in 200 kg/ha nitrogen treatment in both years. As irrigation cycle doubled in 200 kg/ha net nitrogen treatment, population of black bean aphid increased by 177.9 times.

Since Iran is a windy country due to the adjacency to the sea and the existence of Alborz and Zagros plateau, it is expected that the use of wind energy will be developed in near future. The present study aimed at finding the best blade Angle and the best location maximum camber from the chord from among selective levels. Determining the above levels can lead to an increase in fewbladed wind turbines. At first, 3 models of 3 - bladed wind turbines, each with %20 thickness from chord and camber was made in %6. These models were put in wind production mechanism. All data from experiment were statistically analyzed by Mstat - C software & Excel software and Duncantest. The results showed a significant difference between power from the experiment in different wind speeds and location maximum camber. From Duncan test, it was found out that in 3- bladed wind turbines among five levels of angle of attack, angle 15o with an average power of 0.8612 watt, and among 3 levels of maximum camber level of %30 with an average power of 0.8139 watt and among three levels of wind speed, level of 12m/s with an average power 1.078 watt produced the largest among of power from among selective levels. Also it was found out that interaction between variables (angle of attack, location maximum camber and speed) was significant and the model with an angle of attack of 15o, location maximum camber of %30 and wind speed of 12m/s was presented with power of 1.537 watt as the best model for the largest amount of power.

This article analyses the level and typology of different groups of people's participation (PP) in rural cooperatives. As agricultural cooperatives are the main activity in the rural cooperatives, participation was studied in such projects. The type and nature of PP was considered, while choosing the projects for the study. Hamedan province was selected as a suitable case for the study since several cooperatives had been conducted in that area. The selected cooperatives were including: two production cooperative and one natural resources cooperative. The level of PP was explored by how much people were involved in the selected case studies. To increase the validity and reliability of finding of the study, both qualitative and quantitative methods were used to collect the data. The necessary data and information was gathered using several methods of data collection including: survey, direct observation, participatory observation, documentary, group discussion, interview with key participants and PRA techniques. In summary, participation had given some opportunity to people to participate in the development of a part of their own cooperatives. Although their participation had not been actively in early stages of project activities, such as problem identification and planning and decisions made by special groups of people, but a reasonable progress regarding PP has been achieved during the implementation stage, of the proged cycle.