نشریه پژوهش های کاربردی زراعی
پیاپی 89 (زمستان 1389)

To determine the effect of organic fertilizers together with chemical fertilizers as basic on crops yield and soil organic carbon، an experiment was carried out from 1997 to 2002 at Safi-Abad Agricultural Research Center of Dezful،Iran، in a wheat- potato - wheat - canola - corn rotation. The experimental design was a randomized complete block with a split - plot arrangement of treatments with nine treatments and in three replications. Also، in each replication an additional treatment as control plot (no application of organic fertilizer and only use of chemical fertilizers) was included. Organic fertilizer sources were as main plots consisting (farm yard manure، sugar cane bagas compost and wheat straw)، and organic fertilizer rates were as sub plots at 5، 10 and 15 t / ha. The results showed that effect of organic fertilizer amounts on canola grain yield and effect of organic fertilizer sources on potato yield were significant. As compared with control plot yield increases due to application of organic fertilizer in potato، corn، wheat and canola were about 1600، 1400، 750 and 500 kg/ha،respectively. Also، soil organic carbon increased significantly with organic fertilizer application. Therefore، application of FYM or sugar cane bagas compost at 5 t/ha in combination with optimum use of chemical fertilizers are recommended especially for potato and canola.

In order to comparison of different suitable seed vigour tests in relation to seedling emergence and forage yield of four sorghum cultivars (Speed Feed،Jambo،Super Dan and Suger Graze) an experiment was conducted during 2003-2004 in laboratory of Seed and Plant Improvement Institute (SPII) of Karaj، and also a field experiment at exprimental station of Agriclture College of Azad Islamic University، Mardabad، Karaj. germination standard test، seedling vigour classification test، staining index tetrazolium test، electrical conductivity tests and accelerated aging were measured in the completely randomized design with four replications in laboratory. Under field condition، with the randomized complete block design in four replications، percentage and rate of seedling emergeance and forage yield were evaluated. The result of analysis of variance in the laboratory study showed that the differences between the cultivars under the seedling vigour classification tests and staining index tetrazolium were significant at 5% probability، but under the germination standard tests، electrical conductivity and accelerated aging tests were significant at 1% of probability. Under field condition، Suger Graze and Jambo cultivars had lower and higher percentage and rate of seedling emergeance and forage yield، respectively، and also there was significant positive correlation between seed vigour tests، percentage and rate and forage yield. Among the tests under study the seed vigour classification and accelrated aging test for the percentage of emergence seedling vigour classification for the rate of emergence and also staining index tetrazolium and accelerated aging test for forage yield had the closet correlation. As a result، these above mentioned tests had a heigh ability for forage sorghum cultivars percentage of seedling emergence in field prediction and is recommended as the tests to evaluate seedling and seed vigour.

The micronutrient malnutrition has been intensified with rapid increasing in people that had conformed with the expansion of green revolution cropping systems in developing nations. Among the micronutrients reported as becoming deficient worldwide، zinc (Zn) and iron (Fe) are the most important elements. The problem of Zn and Fe deficiency has been intensified by the introduction of high-yielding cultivars of the Green Revolution cereals. Using micronutrient-dense staple food crop varieties is one approach that could be used to increase the micronutrient output of farming systems albeit this approach has never been used to date. This experiment was conducted using a factorial split plot based on randomized complete block design with three replications for comparing grain Fe and Zn concentrations and their relationships with yield and yield components on ten bread wheat cultivars. The maximum levels of Fe and Zn were up to two and three times higher than their minimum levels in wheat grain and straw، respectively. The results of analysis of variance showed significantly differences in source of variations، Fe، Zn، cultivar and their interactions. The best cultivar for Fe contents in straw and grain was shiraz and the best cultivar for Zn contents in straw and grain was kavir. This cultivars، shiraz and kavir، were significantly different from the others. The Fe concentration of the best cultivar، shiraz، was 44 mg Fe kg-1 and the Zn concentration of the best cultivar، kavir، was 48 mg Zn kg-1. The cultivar hamon had maximum yield and yield components. There was a negative correlation between grain yield and Fe، Zn concentrations. However، as grain protein and Zn، Fe concentrations appeared to be positively correlated، Zn and Fe concentrations should respond favorably to selection for high grain wheat protein. For deletion of none or less-efficient traits on grain protein، stepwise regression was used and concluded that 58% of variation between cultivars caused by three characters، 1000 grain weight، grain Fe and grain Zn. Using cluster analysis with UPGMA method and the squared Euclidean distance as a measure of the similarity، the cultivars were grouped into three groups.

In order to study the proper irrigation time of corn crop and determination of optimum management of water consumption in the limited water resource conditions، an experiment based on Randomized completed Block design with 3 replications was carried out in Baekola-Mazandaran agriculture research station during 2003-2004. Water treatment consisted irrigation levels based on 0 (Io)، 1 (I1)، 2 (I2)، 3 (I3)، 4 (I4) times irrigation، and 75 mm for each time was applied during growing season. Water treatments are defined as follows: I1: irrigation during flowering time I2: Irrigation during flowering and vegetative phaseI3: Irrigation during flowering، vegetative phase and tassel emergence I4: Irrigation during flowering، vegetative phase، tassel emergence and grain filling. The result of variance analysis and comparing the average of two years experiments shows that، the effect of irrigation treatment on corn yield was)P<0. 01 (significant. Io and I4 levels had the minimum and maximum yield) 2760 and 11210 kg/ha respectively (. The average water use efficiency (WUE) and irrigation water use efficiency (IWUE) are obtained 2. 43-2. 6 and 2. 72-3. 08، respectively، and the average yield response factor (Ky) for corn crop was determined 0. 99 in this area. I4 for no limited water resource conditions and I3 for 30% reduction of water consumption with 19. 7% of yield decrease in limited water resource can be used. The results of the experiments shows that، flowering stage is the most sensitive one comparing with others. Amount of water requirement in maximum yield is 300 mm. Then، based on obtained results we can decide on water recourses.

Sunn pest Eurygaster integriceps Puton (Hemiptera: Scutelleridae) is the most important pest of cereals in Iran. The implementation of resistant cultivares may prove to be an effective management tactic due to the pest. The study was conducted to evaluate resistance of 13 durum wheat cvs and 43 bread wheat cvs. to the pest through an Augmented design with replicated checks in Abarkouh region of Yazd province،1998-1999. Population density of overwintered adults، 4th and 5th nymphal instars، newly merged adults، damage of overwintered adults on stems and ears، percentage of grain damage، reduced 1000 grain weight، yield، wet and dry gluten content and Sodium Dodecyle Sulphate SDS sedimentation volume were measured. Statistical analysis was done using cluster analysis with Ward’s method. The results indicated that bread wheat cvs.”Tajan”، “Anza”، “Niknejad” and “Moghan-1” and durum wheat cvs. “Massara-1”، “Dipper-6”، “Altar-84” and “Shahdas” were resistant and screened.

A field experiment was conducted during 2005 – 2006 in Agriculture Research centre of Jiroft and Kahnouj to determine the effect of water stress on some physiological and anatomical aspects of alfalfa cultivars. Using a split plot design based on randomized Complete block Design (RCBD) with three replications. The three levels of water stress 1)- severely stressed (irrigation when soil moisture reached to %25 of F. C)، 2)- moderately stressed (irrigation when soil moisture reached to %50 of F. C) and 3)- least stressed (irrigation when soil moisture reached to %75 of F. C) was the main plot factor and five cultivars of alfalfa (1- Yazdi، 2- Nikshahri، 3- Rangar، 4- Bami and 5- Baghdadi) were collected sub plots. Several drought stress indicators، including leaf relative water content (RWC)، cell membrane stability expressed as electrolyte leakage، number of stomata and length of the stomatal aperture characteristics of leaves were examined. The results showed that water deficit stress، significantly reduced relative water content (RWC) values from 86% to 69%. With increasing water deficit stress، electrolyte leakage were increased in alfalfa cultivars the tolerant cultivars to drought (Nikshahri and Bami) maintained higher RWC at severe water stress treatment. The number of stomata and length of the stomatal aperture decreased with increasing water stress level. As overall result is to conclud that، stomata number of alfalfa cultivars tolerant to drought is less and RWC Ratio higher in low water stress condition compared to sensitive cultivars.

In many plant species sensitivity to NaCl is known to vary among growth stages. In order to investigation of germination and seedling growth in some annual medics cultivars exposed to NaCl، an experiment carried out in laboratory in Agriculture and Natural Resources Research Center of Golestan Province in 2007. The experiment was factorial in completely randomized design with 3 replications. Treatments consisted: Medicago truncatula G. Cv. Caliph and Mogul، M. scutellata L. Cv. Sava and Robinson، M. scutellata L. seed’s (cultivar unknown) that collected from saline soil and an indigenous species M. minima and five salinity levels (0، 5، 10، 15 and 20 dS/m). Germination percentage (Gr)، seed germinating rate (Gmax)، ratios of shoot/root length (s/rl) and shoot/ root weight (s/rw) were measured. These traits were significant at 20 dS/m and have difference responses in other salinity levels. Response of M. scutellata L. cv. Sava was better to salinity stress at seedling stage، so that this cultivar continued to grow at 20 dS/m. These results suggest that Sava could be identified as a relative successful cultivar in breeding program for utilization in saline condition. Recovery of germination in Robinson and MSS were highest as compared with the other cultivars.

In order to investigate the resistance of ryegrass to clodinafop propargil، greenhouse trials were carried out during 2007. Treatments included 7 ryegrass biotypes suspected to resistant to clodinafop propargil and a susceptible biotype collected from Fars province. Greenhouse trials included two distinct section، screening tests and dose response. Screening test was conducted for 7 biotypes as a completely randomized design with 4 replications using recommended dose of clodinafop propargil (64 g ai/ha). Dose response was also conducted using 9 dose of clodinafob propargil (0-32 time of recommended dose). Screening test was conducted performing EWRC visual rating، number of survived plant after herbicide application (NO) and dry weight of shoot biomass survived plant after herbicide application (DM). Number (DRN) and dry weight (DRD) of survived ryegrass after herbicide application were also measured in dose response test. Results indicated that RF2، RF4، RF6 and RF1 showed highest resistance to clodinafob propargil and all of the EWRC، NO، DM، DRN and DRD indices confirmed it properly. It is concluded that screen test using recommended dose could be advised as the powerful method of preliminary determination of resistant biotypes. It is also suggested to use fresh weight to standard check index as well as DRN and DRD due to different results in dose response test.

Intercropping has an important role in optimum using of production factors and often increase yield and income in unit area. In order، this experiment was carried out to study of tomato yield and income in intercropping with snap bean. This research was conducted at factorial experiment based on randomized complete block design with 4 replications in Kahriz station for two years. The factors were cultivation system (tomato sole cropping and intercropping with snap bean) and spacing between rows of tomato (80، 100 and 120 cm). In intercropping، tomato was planted in one side of ridge and snap bean in other side of ridge، but in sole cropping only tomato was planted in one side of ridge. In order to comparison sole cropping and intercropping، yield and yield components for tomato and snap bean yield and land equivalent ratio (LER) was studied. Treatments were evaluated with risk budgeting. Results indicated that yield per hectare، yield per plant and fruits number per plant in sole cropping was more than intercropping. Interaction effect of cultivation system and spacing between rows was significant at %1 level only on fruits number per plant. The most of fruits number per plant was recorded in sole cropping with 120 cm. At all spacing between rows، tomato yield at sole cropping was more than intercropping and LER was less than one. Based on risk budgeting، intercropping with 100 cm had maximum gross profit. Therefore، in severity changes of tomato price، intercropping prevent from fluctuations to and supply of tomato through balance position.

In order to evaluation of genetic variation in segregating population، 374 F3-Plants (lines) were planted in augmented design with four check varieties (Azar-2، 87-Zhong291، Kharchia and Superseri≠2). These check varieties planted in Randomly Complete Block Design with 7 replications. For germination of seeds، the farm was irrigated just one time. During and at the end of growth season we measured some agronomic and morphological characters such as seed yield and it’s component، plant height، day to flowering، peduncle length، awn length، harvest index، biological yield and etc. After adjusting the data، some statistical indices were calculated. The results of analysis showed the diversity between experimental materials. Standard deviation of plant height was the highest and for harvest index was less. In order to evaluation of correlation between traits، Pearson correlations were calculated that the importance of peduncle length was cleared. But awn length and spike weight didn’t show any correlation. For deletion of non-efficient or less-efficient traits on seed yield، stepwise regression was used and concluded that 98% of variation between genotypes were caused by three characters (spike weight، harvest index and biological yield). For decreasing of variables and better conclusion، Factor analysis was used that four factors were identified. Finally، because of high variation in analyzed population and high potential of the population for line selection، to reaching maximum purity، management of the population was recommended.

To increase yield، nitrogen use efficiency (NUE) and nitrogen apparent recovery fraction (NARF) in canola (Brassica napus. L.)، an experiment was carried out in Khosrowshar Research Station farm in 2006-07. The experimental design was RCBD with 7 treatments with 3 replications. The treatments included T1=The control (Applying all macro and micronutrients based on soil test analysis except N); T2= 400 kg ha-1 of urea in 2-split applications (pre-plant and top-dressing); T3= 400 kg ha-1 of urea in 3-split applications (pre-plant and 2 times top-dressing); T4= 400 kg ha-1 of urea in 5-split applications (pre-plant and 4 times top-dressing); T5= 80 kg ha-1 of pre-urea and 400 kg ha-1 of urea in 4-split applications with irrigation water; T6= 100 kg ha-1 of SCU as the base fertilizer and 320 kg ha-1 of urea in 4-split applications with irrigation water and T7= 200 kg ha-1 of complete macro fertilizer as the base fertilizer and 320 kg ha-1 of urea in 4-split applications with irrigation water. The existing extra nutrients in complete macro and SCU fertilizers were added to the other treatments. After harvesting، grain yield، NUE and NARF were measured. The results revealed that the yield، NUE and NARF for T2، T6 and T7 were increased significantly at 1% level. The maximum grain yields (6565 and 6484 kg ha-1)، NUE (18 and 17 kg kg-1) and NARF (52 and 49%) were obtained again from T6 and T7 treatments. In order to reduce N loss، it is therefore، recommended that instead of the application of 1/3 pre-plant urea، SCU or complete fertilizer should be used. Despite proven superiority of complete and SCU fertilizers over pre-plant urea، it is strongly recommend substantiating this finding in some important canola growing provinces of Iran، since this practice increases the canola grain yield، NUE and NARF. Overall results revealed that substituting of SCU and complete macro fertilizers with pre-plant urea is advisable in canola plantation areas.

The critical period for weed control (CPWC) is the period in the crop growth cycle during which weeds must be controlled to prevent unacceptable yield losses. A field study was conducted in 2006 in the University of Birjand to determine CPWC in Birjand region using a randomized complete design with 14 treatments and three replications. The treatments consisted of two different periods of weed interference، a critical weed-free period and a critical time of weed removal were imposed at V3، V6، V9، V12، V15، and R1 (based on phenological stages of corn development) with a weedy check and a weed-free check. The CPWC was determined by fitting non-linear regression models of Logistic and Gompertz equations to the data in range of 2. 5، 5، 10 and 20% of acceptable yield loss levels. The CPWC was from 5- to 15-leaf stage (19-55 DAE) to prevent yield losses of 5%. This period to prevent yield losses of 2. 5، 10 and 20% was 4- to 17-leaf stage (14-59 DAE)، 6- to 12-leaf stage (25-47 DAE) and 8- to 9-leaf stage (31-36 DAE) respectively. The leaf area index of corn were significantly decreased by weed competition in both weed free and weed infested treatments (P<0. 01). Results also showed that there was a positive correlation between forage yield and LAI of corn at silking stage when competing with weeds (r= 0. 95) and could be considered as an index of weed effect on corn yield.

This study was conducted in order to estimation of narrow sense heritability of leaf، stem and spike dry weight and genetic correlation between these traits with yield، biomass and harvest index. Tow parents Sardari and SON 64 with 50 F3 line resulted of cross between them was planted in RCBD design in three replications. Measuring of these traits sampling before anthesis stage. Estimation of genetic parameters was conducted in attention to important of genetic variation between and within generations. Estimation of narrow sense heritability for dry weight of leaf، stem and spike was 69. 5، 68. 6 and 56 percent، respectively. These results indicated role relatively high of additive effects on control of these traits. Therefore، from selection on the basis of these traits، favorable genetic advances will except. In this study، dry weight of leaf had negative genetic correlations with yield، harvest index and positive genetic correlation with biomass، and dry weight of stem and spike. Spike dry weight had positive genetic correlation with yield and biomass. In attention to high heritability and positive genetic correlation estimates for dry weight stem and spike with yield، these traits proposed for selection and improvement of yield traits of this population.