AGROECOLOGY JOURNAL (JOURNAL OF NEW AGRICULTURAL SCIENCE)
Year:2009 | Volume:5 | Issue:16|Papers Count:13

   To determine the response of wild rocket, Eruca sativa to low doses of 2,4-D and competitive wheat varieties, a factorial experiment based on randomized complete block design was conducted at the research station of Iranian institute of plant protection, Karaj. The experiment included 2 wheat varieties (Shiraz and Tabassi), 4 herbicide doses (0, 0.5, 0.75 and 1.0 Lit.ha-1) and 4 wild rocket densities (0, 25, 50 and 75 plant.m-2) with 4 replications. The results showed that reducing herbicide dose up to 25 percent did not have any adverse effect on yield. Grain yield of Shiraz variety, without herbicide treatment, was more than that of Tabassi in high dosage herbicide treatment and so the need for herbicide application could be decreased using competitive wheat varieties. Shiraz also had more yield than Tabassi cultivar in all wild rocket densities. The results revealed that Tabassi, a less competitive variety, was more dependent on herbicide application than Shiraz. did It concluded that the selection of good variety of wheat for competition with wild rocket was more effective than chemical control.

In order to study the effect of irrigation regimes on yield and yield components of three bread wheat cultivars, Triticum aestivum L., an experiment was conducted at the research farm of Islamic Azad university, Khorasgan Branch in 2004-2006. The experiment was carried out as split plot based on randomized complete block design with four replications. Three irrigation regimes (based on 70 mm (I1), 90 mm (I2) and 110 mm (I3) pan evaporation) were arranged in main plots and three wheat cultivars including Ghods, Mahdavi and Roshan-backcross were planted in sub-plots. Results showed that I1 and I2 treatments was not significantly different in most yield and yield components measured traits. I3 treatment significantly reduced yield and yield components, but water use efficiency was not affected. Significant differences were observed in number of grain per spike, 1000 kernels weight and grain yield among cultivars. Ghods and Roshan-backcross had highest and lowest numbers of grain per spike, 1000 kernels weight and grain yield, respectively. Based on sensitivity and tolerance indices to water stress, Ghods showed better yield stability in response to increased water stress. The results indicated that irrigation of wheat after 90 mm cumulative pan evaporation could be save about 22% of irrigation water with no significant loss in yield, under conditions similar to this experiment.

   In order to study the effect of plant distance and tuber size on yield and yield components of potato varieties, a factorial experiment was conducted based on randomized complete block design, at research station of Islamic Azad university, Tabriz branch during 2003-2004. Factors were variety in two levels, seed distance on planting rows in two levels and four levels of tuber size. Results of two year combined analysis showed that three way interaction of "year*variety*plant distance" for main stem numbers trait was significant, expressing different response of variety and plant distance upon mentioned trait in two years. Also interaction of year*variety, year*plant distance and year*tuber size for yield was significant, that represented different response of varieties for yield and different impressibility of yield by plant distance and tuber size during two years. Results revealed that Mourn was superior to Cosmos variety in most studied traits. Plant distance of 20 cm on implant rows increased yield and main stem numbers and 25 cm planting distance was impressible for production of less small and more moderate and large tubers. Tuber size of 35-55 mm was the best size in all studied traits. Overally, the results showed that treatment compound of Mourn variety, 20 cm seed distance and 35-55 mm tuber size was the best treatment. However, while the farmers have to cut tuber, the treatment compound of Mourn variety, 20 cm seed distance and oversize of 55 mm tuber was the most desirable treatment. According to different responses of potato varieties to plant distance and tuber size, incorporation of variety, plant density and tuber size.should be regarded to obtain high yield.

The study was carried out to evaluate the effect of integrated mechanical and chemical weed control aspects on yield and yield components of corn, Zea mays L., in 2005-2006 at agricultural research station of weed research department of Iranian research institute of  plant protection in Karaj region. The experiment was designed as split plot based on randomized complete block design with three replications. Factors were cultivation numbers (no cultivation or control, one time at 10 cm height of corn, and two times at 20 and 30 cm height of corn) and five chemical treatments including mixture of 1 lit. Atrazine and 5 lit. Alachlor (recommended dose), reduced doses of Atrazine and Alachlor’s mixture up to 25%, 50%, 75%, and a control. Yield and yield components including numbers of row/silk, numbers of grain/row and 100 grain weight were measured and analyzed statistically. The results showed that the effect of all treatments on all measured traits were significant. Among different mechanical treatment levels, two times applying of cultivator was better than one times cultivation and control. 75% reduced dose of Atrazine and Alachlor’s mixture and recommended dose of the herbicide were superior to the others and resulted in decrease of weed dry matter and increased yield and yield components of corn. Finally, it was recommended that mentioned integrated weed management approaches should be applied to reduce herbicide use, supress weeds and increase yield and yield components of corn in Karaj and similar regions.

This study was conducted to evaluate the effect of drought stress on twenty chickpea genotype by analyzing ecophysiological traits in field condition. Field experiments were carried out during 2007-2008 at the research farm of dryland agriculture research institute, Sararoud, Kermanshah, in two separate irrigated and non-irrigated conditions with randomized complete block design in four replications.Yield and yield components, leaf area index, the distance of the lowest pod to soil surface, numbers of main stems, length of the main stems, days to flowering and maturity were meseured in each experiment, separately. Drought resistance indices of SSI, STI, TOL, GMP, YI, MH and MP were calculated based on seed yield under irrigated and non-irrigated conditions. Results indicated that values of studied traits significantly decreased in non-irrigated experiment compared to irrigated one. Days to flowering and the distance of the lowest pod to soil surface showed most positive and negative correlations with yield, respectively. Among drought indices, STI, GMP, MH, and MP were introduced as the best indices for selection of resistant genotypes. Based on cluster analysis of studied genotypes, Azad, ILC.482 and ILC.1799 were categorized as the same group and were the most  resistant genotypes to drought stress.

   The aim of this study was to evaluate the sugar beet farmers’ knowledge, attitudes and skills on optimal on-farm soil management practices and to identify and determine the most important distinguishing factors of their behavior domains on soil management. The methodological approach in the research was a descriptive and causal-comparative study of the survey type. The target population in the study was the sugar beet farmers of Khorasan-Razavi province (n=33000). Using a multi-stage cluster sampling technique, 380 farmers were selected as a statistical sample. Finally, 98.5% questionnaires were collected and analyzed (n=375). The content and face validity of the instrument was specified after several times of review and correction by the faculty members of agricultural extension and education, agronomy and soil science departments at Tarbiat Modarres university, several experts of Jihad e Agriculture ministry and the agricultural sector of the sugar factories in Khorasan-Razavi province. The reliability of analysis was conducted through 30 questionnaires and Cronbach’s Alpha values for the section of behavioral domains of the instrument were estimated between 0.71-0.87 using statistical SPSS software. Considering Venn diagram in relation to the triple domains of studied sugar beet farmers’ behavior, results showed that about 11.2% (42 sugar beet growers) were identified as qualified farmers. The results of the stepwise discriminant analysis with Wilks’ Lambda procedure and partial F-test criteria revealed that educational level, extension contacts, extend of irrigated cultivation, farmers’ age and social status were the most important distinguished variables of farmers’ behavioral categories. Generally, mentioned variables could correctly classify 66.9% of all subjects based on the discriminant functions.

Walnut Anthracnose caused by Gnomonia leptostyla (Fr.) Ces. & De Not. is one of the most serious foliar diseases of Persian walnut in absence of chemical treatments. The disease may result in premature defoliation, and fruit falling and reducing tree vigor and age in favorite conditions. Application of resistant cultivars is one of the main ways for disease management. In this study, interaction of 11 different walnut cultivars were evaluated against this disease. An experiment was carried out in greenhouse condition as completely randomized block design with 12 treatments and three replications. Conidia suspension of three fungus isolates with 105 per ml. concentration was atomized on seedling leaves which had been placed in three rows and 22 columns arrangement. Seedlings incubated for 48 hours at 21±2 oC in greenhouse under plastic covers and then the covers were removed. The seed plants were set around the grafted plants as guard. Macroscopic symptoms were occurred two weeks after primary inoculation. The numbers and diameter of spots were recorded one and two months after inoculation. Disease severity in seed cultivars was much more than grafted plants. According to the statistical analysis, Z67 and K73 cultivars showed more resistance in comparison with others and Z67 was the most resistant one. The cultivars Ser, Vina, Hartley, Ronde de Montignac, Lara and Franquett had moderate to weak resistance and the cultivars Z63, Z60 and Pedro were all susceptible to the disease.

In order to determine the physiological limiting factors of yield in different varieties of wheat, Triticum aestivum L., an experiment was conducted as split plot in a randomized complete block design with three replications in research farm of Islamic Azad university, Saveh branch in 2006-2007. Two large grain, Mahdavi, and small grain, Falat, wheat varieties were the main factors and removing flag leaf blade, removing three upper leaves, thinning of 50 percent of plants, removing of flag leaf blade and thinning of 50 percent of plants, removing of three upper leaves and thinning of 50 percent of plants and a control were considered as sub factors. The analysis of data showed that thinning of 50 percent of plants increased grain dry matter significantly in both cultivars. Removal of leaves decreased grain dry matter in Mahdavi cultivar more than Falat. Results showed positive reaction of small grain cultivar than large grain one in case of source limitation.

This study was conducted to identification of Fusarium spp. as casual agents of lentil wilt, damping off and root rot diseases and comparison of their pathogenicity in Fars province during growing seasons of 2007-2008. Lentil fields with yellowing and wilting symptoms were visited and 115 samples were collected from which totally 62 isolates of Fusarium spp. were obtained. Isolates then were identified and accomodated in five species of Fusarium oxysporum, F. solani, F. equiseti, F. avenaceum and F. sambucinum with 46.7, 35, 8.3, 5 and 3.3 percent frequencies, respectively. This was the first report of F. avenaceum in lentil fields of Iran. Pathogenicity test was conducted and disease severity were rated according to the scale proposed for Fusarium diseases of lentil. The results indicated that F. oxysporum was the most important pathogenic species in the lentil farms of Fars province.

This experiment was conducted in order to study and evaluation of drought resistance indices of 12 bread wheat genotypes in irrigated and non-irrigated conditions in Sarableh and Mehran regions of Ilam Province in 2004-2005. Morphophysiological traits of wheat genotypes were measured depending on the type of each trait under two non–stressed, irrigated, and drought stress, non-irrigated, conditions in a randomized complete block design with three replications. The results indicated that the plant height, 1000 kernel weight, seed yield and harvest index were decreased by drought stress. Under drought stress condition, the spike numbers per m2 and 1000 kernel weight had a high positive correlation with seed yield. In irrigated condition, high positive correlation was observed between the seed yield and both the spike numbers per m2 and harvest index. Results of calculating drought resistance indices in stress and non–stress conditions indicated that MP, STI, and GMP indices had the highest correlation with seed yield and can be used for selecting drought resistant varieties. Acconding to drought resistance indices and cluster analysis, Mohammadi was known as the most resistant variety to drought stress. In total, Mohammadi, Gahar, Koohdasht and Ghanari varieties were the most resistant varieties and produced the highest yield.

In order to compare Iranian cold region wheat lines and landraces for yield and yield components, an experiment was carried out in 2005 at the Miyandoab agricultural research station. In this experiment 45 landraces of winter wheat collected from different cold regions of Iran were planted at a randomized complete block design arrangement with three replications. Traits under study were, plant height, biological yield, grain yield, harvest index, number of spikelets per spike, and numbers of kernel per spike. Results showed significant differences of lines in studied traits. Lines no. 29, 32, 36, 37 and 38 had higher harvest indices. It was also revealed that lines no.15, 18 and 13 produced the highest grain yield and yield components and therefore can be used in plant improvement programs for higher harvest index, dry weight, and grain yield. Path coefficient analysis of harvest index showed that the most effective traits for increasing harvest index were biomass weight and grain yield and these traits determined 90.2% of harvest index variations. Path coefficient analysis of grain yield also showed that the most effective traits for increasing grain yield were number of spikelets per spike and plant height and these traits determined 35.7% of grain yield variations.

Mycorrhizal fungus can increase plants tolerance to stress. To study the effect of the application of mycorrhizal fungus on morphological characters and nutrients contents of Karon dar Kavir barley, Hordeum vulgare, cultivar, an experiment was conducted as a factorial based on randomized complete block design by two factors in greenhouse of research farm of Islamic Azad university, Saveh branch during 2006-2007. First factor was applying of mycorrhizal fungus, Glomus interaradices, or not and the second factor was salinity levels. Plants were grown in five Kg. capacity pots under 0.6, 8 and 13 ds/m NaCl salinity conditions in the greenhouse. Salinity decreased root and shoot dry matter, shoot fresh weight, plant height, length of spike, number of tillers and number of leaves in a plant, but did not have significant effect on number of leaves per stem. Mycorrhiza inoculation increased all characters, excpect number of leaves per stem in stress and non stress conditions. Mycorrhizal fungus increased barley tolerance index especially in higher salinity conditions and plants showed higher mycorrhizal dependency in salinity conditions. Inoculated plants also showed higher nutrients content in all conditions than non-inoculated plants. More tolerance of inoculated plants to stress can be a result of their higher nutrients content in comparison with non-inoculated plants.