فهرست مطالب i. eskandari

In order to produce varieties of barley that tolerate drought and cold, Artan variety was entered into internal tests of the cold and temperate cold stations of the Dryland Agriculture Research Institute through the international center of ICARDA in the form of the of segregating populations (F3 generation) in 1997-98. Genetic purity was achieved by the modified bulk method. Then, during several years, it was evaluated in Maragheh, Shirvan, Ghamlo, Sararoud, Zanjan, Urmia and Ardabil stations in yield trials and yield stability experiment. The Artan variety with an average seed yield of 2.142 Kgha-1 had 11% higher seed yield than the Abidar check variety. Artan had relatively early maturity, height and high thousand-seed weight. Artan variety has general adaptability and good yield stability, facultative growth habit, resistance to seed shattering, tolerance to cold and drought, relative early maturity, high plant height (83 cm) and high thousand-seed weight (42 gr). It has also good level of resistant to yellow rust and brown rust diseases of barley. Artan variety was selected and released as a new cultivar due to its high yield and favorable agronomic characteristics for planting in the cold and moderately cold regions in rainfed areas of the country.

One approach to improve remote sensing techniques relies on the spectral response to infer soil and crop properties. The aim is to develop methods that can identify inferring factors so that they can be removed during later analysis. Differences in spectral reflectance can be the base of detecting crop residue and growth of crop in different tillage management. This experiment was conducted under dryland conditions to determine the influence of crop residue remained on soil surface in conservation and conventional tillage systems on soil moisture, canopy temperature and grain yield and also yield components of a winter wheat. Remotely sensed data were acquired three times prior to canopy closure using a handheld thermal imager (7,000 to 14,000 nm). According to results, differences between yields were significant (P<0.01). The yield of no-till treatment with all previous crop residue (NT2) was slightly more than that for no-till with only standing previous crop residue (NT1). Also, the yield of reduced tillage system (CD) was 31% higher than that for conventional tillage system (MD). A similar trend was observed for wheat biomass yield. No-till treatment increased soil moisture content in the 0–30 cm layer. At the flowering stage, soil bulk density in 0-20 cm depth was significantly lower for NT2 (the no-till with total residue) compared to MD and CD treatments. During the flowering stage, residues in NT1 and NT2 lowered the canopy temperature by 3-9 °C over other treatments (MD and CD). Results of this study indicated that for a dryland vetch-winter wheat cropping system with annual precipitation of 251 mm, NT2 had higher grain yields (762 kg ha_1) than that obtained by MD system.

Conservation tillage practices and proper seeding depth of wheat for early emergence before the first effective rainfall are very important in dryland cold regions. An experiment was conducted during 2001-2004 cropping seasons at the Dryland Agricultural Research Station, located in the northwest of Iran. The main objective of this study was to find the optimal seeding depth for wheat production in dryland. The treatments were, three wheat genotypes (Azer 2, Ogosta/ Sefid and Fenkang15/Sefid) as the main plot and three seeding depth (2-4, 4-6 and 6-8 cm) as subplots in strip plot design with three replications. Data were analyzed by the analysis of variance method. When the F-test indicated statistical significance at the 1% level, means were compared by the Duncan, s new multiple range test. Results showed that increase in seeding depth decreased number of heads per square meter, kernel size, biomass and grain yield significantly. The highest grain yield was obtained at 4-6 cm seeding depth in Azer 2 with 2580 kgha-1. Genotypes differed significantly in grain yield. Fenkang15/Sefid with 2149 kgha-1 had the highest grain yield. The number of heads per m2 had the main effect on yield increase. The highest number of heads per m2 (338 head per square meter) belonged to 2-4 cm seeding depth .

In order to evaluate the effects of conventional, mechanized planting and direct drilling on soil moisture and grain yield of chickpea, this experiment was carried out in RCBD with 4 treatments and 4 replications at Maragheh Dryland Agricultural Research Institute. Field studies were conducted on a clay loam (fine mixed, mesic, veritc calcixerepts) soil on wheat stubble for 3 years (1995-1998). Results showed that there was significant difference in soil moisture content of treatments after planting and before harvesting times. Soil moisture content in direct drilling, after planting and before harvest were 34.75% and 16.25%, respectively. Direct drilling stored soil moisture better than other treatments. The results of combine analysis showed that there was a significant difference in yield in different treatments. Direct drilling and mechanized planting methods produced higher crop seed yield by 891 and 811 kgha-1 respectively. Conventional planting methods (broad casting and covering by diskharrow, broad casting and covering by mould board plow) had the lowest yields (627 and 555 kgha-1).