JOURNAL OF CROP ECOPHYSIOLOGY (AGRICULTURE SCIENCE)
Year:2009 | Volume:3 | Issue:11|Papers Count:8

The effect of seeding dates were evaluated on growth and yield of rice under direct seeding in a split plot experiment based on RCBD during growing season of 2007. Four seeding dates were April 30 and May 10, 20 and 30 using three cultivars (Hashemi, Tarom and Elpaso) with four replications. Seeding dates and cultivars were assigned to main and sub plots, respectively. The results showed that date of seeding did not have any significant effect on the number of panicle per m2 while the effect of date of seeding on seed yield, number of non-bearing tillers per m2, length of panicle, number of full and empty fruits per square meter and plant height were significant.Second date of seeding produced 5029 Kg per hectares with plant height of 111 cm, Elpaso produced 5378 Kg per hectare, the highest seed yield, Hashemi with height equal to 117 cm had the highest plant height. Date of seeding by cultivar interaction for number of non-bearing tillers, number of panicles per m2, length of panicles, number of full and empty seeds were significant. Elpaso, on second seeding date, produced highest full seed per m2 (19270), number of panicle per m2 (322), and highest yield (6854 Kg per hectare).

A split plot experiment based on completely randomized block design with 3 replications was performed to evaluate the effect of K-humate on yield of three potato cultivars under different irrigation regimes. Main-plots included four irrigation treatments 1- irrigation every seven days, 2- irrigation every seven days+spraying with K-humate, 3- irrigation every ten days, and 4- irrigation every ten days+spraying with K-humate, as spray, 250 ml in 300 liter water per ha in three growth stages, (germination, before and after tuberization). Sub-plots included three potato cultivars (Caeser, Satina and Agria). Results showed that irrigation treatments had significant effect on days to flowering, stem per plant, tuber per plant, tuber yield and marketable tuber yield. Differences among cultivars were significant in tuber per plant, marketable tuber number and dry matter percentage. The maximum tuber yield was obtained under normal condition and spraying with K-humate belonged to Caeser and the minimum yield under stress condition to Agria.

Effects of water deficit stress and plant densities on yield and some morphological and physiological characteristics of two sunflower (Helianthus annuus) hybrids was investigated. The experiment was conducted as a split factorial based on randomized complete block design whit three replications at Research Station of the Islamic Azad University of Tabriz in 2006. Treatments were Reccord and Azarghol, four levels of water used were control, 75%, 50%, 25% of available soil moisture and plant densities of 80, 90 and 100 thousands plants per hectare. Row spacing was 60 cm and plant intervals within rows were 16, 18 and 20 cm, respectively for the three plant densities.Results indicated that imposing achenes to drought stress decreased seed and oil yield per m2, weight of fruit wall, empty seed weight and content of chlorophyll (p<0.01).Furthermore, effects of variety on levels of stress was significant in seed and oil yield per m2, empty fruit weight. Azarghol and Reccord under control condition produced highest seed yield and oil yield per m2. Results also indicated that the effects of plant densities on seed yield per m2 (p<0.01) was significant. Azarghol and Reccord at 10 plant densities per m2 had the highest seed yield per m2 and Azarghol and Record at 8 plant densities per m2 had the least seed yield per m2. Results also indicated that Azarghol hybrid by 90000 plants /h-1 and Reccord at 100000 plants per hectare at 25% available water had highest and lowest empty achenes, respectively.

Autosomal recessive genetic diseases in cattle are breed-specific and one of them is bovine leukocyte adhesion deficiency syndrome (BLAD). It is a genetic disease that affects especially the Holstein breed. The molecular basis of BLAD is a single point mutation (adenine to guanine) at position 383 of the CD18 gene, which caused an aspartic acid to glycine substitution at amino acid 128 (D128G) in the adhesion molecule CD18. Recognition of these disorders presently was carried out by PCRRFLP with TaqI and HaeIII enzymes. In this research, DNA samples purified from bulls and then investigated the quality and quantity of extracted DNA.101bp of CD18 gene amplificated and electrophoresis carried out on 2% agaros gel. Digested products run on 10% polyacrylamide gel and then stained by etidium bromide. None of the bulls under study were found to be BLAD carrier and all recognized as TL code.

During searching of alternatives for available fumigants to control stored product pests, acetone vapors were found to be toxic on stored product pests. Acetone is a metabolic product in living organisms from plants to higher animals, including insects.Hence, this study was carried out to evaluate the effect of acetone vapors against two important stored produt pests including: Indian meal moth, Plodia interpunctella (Hubner.) and Lesser grain borer, Rhyzopertha dominica (F.). In this study the experiments were performed in empty and full containers. Concentrations of vapors used were 0, 15, 30, 60 and 120 ml/l for empty containers and 0, 120, 200, 280 and 360  ml/l for full containers with gas exposure times of 24, 48 and 72 hours. Experiments were carried out on 15°C and 27° C with four replications. In all experiments, the percentage of mortality increased with extending exposure time. Various temperatures caused statistically significant different insects mortality. Consequently, the mortality percentage in higher temperature was greater, due to the non-uniform dispersion of acetone vapors in empty containers, the mortality of insects were different in various levels of containers. The mortality at lowest levels was higher than upper ones because of acetone vapors aggregation. Due to surface absorption of acetone vapors, by corn seeds, in full containers, mortality in different levels was not the same. However, due to surface absorption of acetone vapors by corn seeds it was greater in high levels (near acetone release point) than middle and lowest levels. In all of the experiments, the mortality percentage increased by increasing the concentration of acetone. In this research the Indian meal moth pupa was the most resistant developmental stage.Results of the treating corn seeds with different concentrations of acetone revealed that acetone did not affect the germinability of the treated corn seeds.

In this study, economic and environmental targets, optimum cropping patterns were determined by using Lexicographic Goal Programming (LGP). Results showed that farmers, decision making will be facilitated under adverse environmental condition by using the model and it is possible to determine preferred confidence level for any constraints of the model easily. In environmental structure, cultivated area decreased, sugar beet had maximum cultivated area and onion eliminated from cropping pattern related to current condition in economic structure, corn had maximum cultivated area. In linear programming model, total cultivated area decreased, wheat had maximum cultivated area and sugar beet eliminated from cropping pattern.Furthermore, in comparison with existing condition, the amount of water and fertilizer consumption in economic structure decreased and consumption of water, fertilizer and machinery showed decreasing in environmental structure related to economic structure and current conditions. On the basis of findings, by considering environmental targets, there is also a possibility for increasing profit and productivity of inputs related to current condition.

Increasing wheat production area due to some environmental limitations is not a possible strategy. Thus, only rational is to enhance the yield per/hec. The objective of this study was to measure the technical efficiency of wheat growers and to identify the inhibiting factors for yield increase under irrigated wheat of Ilam province. This study employs a tranlog frontier production to examine and estimate technical inefficiency of Ilam wheat farmers. The results showed that the average technical efficiency level is %78. Also, wide dispersion of land units is recognized as a preventing factor in wheat production. The results also indicated that with increasing of farmers' experience, technical inefficiency can be decrease and wheat farmers may use inputs more efficiently. There is significant and positive relationship between increasing wheat technical efficiency and farmers' experience.

This study was initiated to identify the cause of agricultural price fluctuations between domestic producer prices and their world prices. Present findings reveal that sources of beef, veal and poultry price fluctuations are of great importance. To achieve the goal, annual information of 2001-2007 concerning beef, veal and poultry prices were used. Study procedure was based on decomposition method developed by Liefert who uses the domestic producer prices and world prices from exchange rate and import tariff rate. Results obtained indicated that a beef and veal market for 2001-2003 and 2006-2007 changes in tariff highly contributed to the domestic prices, although during 2003-2005 world prices played a great role. The poultry market for 2001-2004 and 2006-2007 changes of tariff rate drastically was involved in fluctuation of domestic producer prices and world prices for 2004-2006. Also an important factor that affects producer price is about incomplete transmission of changes in trade prices of domestic producer prices and world prices, where the incomplete transmission is mainly caused not by policy but rather by undeveloped market infrastructure. In the end, it should be mentioned that the most important sources of price fluctuation is about world prices and tariff rates that the country has the acceptance of world price.But, it may have effect on changes in tariff rate, and there should appear main strategy which it will be caused by avoidance of daily life strategies in tariff and looking ahead to price rate systematizing. Also, long run ambition in strategies should be noticed.