Iranian Journal of Field Crops Research
Year:2009 | Volume:7 | Issue:2|Papers Count:41

Manure application is one of the most important sources of weed seed for infestation farms and orchards. Temperature and moisture are two important factors influencing weed seed viability within manure. Therefore in order to study the effect of temperature, and duration of weed seed in manure on weed seed viability, a series of experiments were conducted at the laboratory of weed sciences, Ferdowsi University of Mashhad; by using a Completely Randomized Design (CRD) with factorial arrangement and 3 replications. Treatments included different temperatures (25, 40, 50, 60, and 70°C); and duration of weed seed in manure (0.25, 0.5, 2, 3, 5, and 7 days); weed species (redroot pigweed, canarygrass, common lambsquarters, and Flix weed); and manure (cattle manure or no manure).The results showed that seeds of all weed species were killed by keeping at 50°C after 5 days, but seeds of common lambsquarters could survive at 60°C for 12 hours. Also high temperature shortened the mean germination time (MGT) of all species. There were significant differences among weed seed species with regard to temperature tolerance and duration of weed seeds in manure, which may be related to seed structural and physiological properties. In conclusion, seeds of common lambsquarters and flixweed species showed the highest and least tolerance to temperature and durability in manure, respectively.

One of the adverse effects to plants in the presence of salinity is the reduction in nitrogen uptake. The objective of this experiment was to determine response of wheat cultivars (cvs) CR11(Iranian salttolerant), Ghods(Iranian salt-sensitive) and Kharchia - 65 (as standard salt-tolerant) to the rate of shoot and root nitrogen accumulation at anthesis and harvest maturity when exposed to different concentrations: 0, 100, 200 and 300 mol m-3 of mixture of NaCl and CaCl2 in 5:1 molar ratio and three levels of amonium nitrate (0, 2 and 4 mol. m-3) in semi-controlled environment and sand culture medium. The results showed that, although nitrogen accumulation was decreased with increasing level of salinity specially before anthesis, but the nitrogen concentration in different organs (roots, leaf, stem and grain) was not changed necessarily, and depend on plant ability to nitrogen absorption and biomass production, the cultivars responded differently to salinity. N application at 100 and 200 mol.m-3 of salinity caused better nitrogen uptake efficiency and nitrogen utilization efficiency and consequently better nitrogen use efficiency and rise in N content, but at 300 mol.m-3 of salinity, nitrogen not only did not adverse effects of salinity but also caused a reduction in nitrogen content of plant. Although, nitrogen reduced the adverse effects of salinity, however the form of nitrogen is important and it needs to be studied in detail.

Dryland wheat is highly dependent on climatic factors and therefore yield is fluctuating accordingly. Since wheat plays an important role in food security, beforehand wheat yield prediction can help government decision-making. Possibility of predicting dryland wheat yield by precipitation and edaphic data was studied using regression models. Dryland wheat yield data during 1362-83 were collected from Jahad-e-agriculture of Khorasan. Eight major wheat growing areas (Bojnourd, Shirvan, Farouj, Esfarayen, Dargaz, Quchan, Mane-Semelghan and Raz-Jargalan) which have maximum average yield and cultivated area were selected. The precipitation data was used in the forms of annual (beginning from Mehr), monthly during growing season (Aban to Khordad) and total growing season precipitation (8 months from Aban to Khordad). In order to evaluate edaphic data such as soil texture, moisture content at field capacity (FC) and permanent wilting point (PWP) and also soil available water, soil samples were taken. To calculate the moisture content at FC and PWP, standard transfer functions were adopted. To obtain the regression models, some Excel, Minitab and Sigma stat software were used. The regression methods included simple regression, multiple linear regression followed forward stepwise regression. The results obtained from 10 different regression models showed that the most important parameters for dryland wheat prediction were precipitation in Farvardin, Khordad, Aban and Esfand, soil moisture content at FC and PWP and soil clay percentage. According to regression coefficient of models, the best equations were those models which used 1) precipitation in Farvardin, khordad and Aban and soil moisture content at FC and PWP (R2 = 0.78, RMSE= 27.3) and 2) total precipitation during growing season, soil clay percentage and soil moisture content at FC and PWP (R2 = 0.71, RMSE= 33.9).

Seed storage proteins of wheat grain are the most effective agents in bread making quality. Suitable dough should have high extensibility; therefore it is necessary to pay more attention to low molecular weight (LMW) due to its role in dough extensibility. Since group B is the most important component of LMW and has the largest allelic variation, the polymorphism of this subunit was studied using ALP molecular marker. On the base of polymerase chain reaction (PCR), six groups of bands varying in length from 450-550bp were detected in using gel electrophoresis, indicating that allele variation in Iranian bread wheat cultivars. Among tested cultivars, the highest allele frequency belonged to r2 with 500bp length and the lowest allelic frequency was belonged to r3 with 470bp length. The results of cluster analysis showed that cultivars are put in three distinct groups. Relationship allelic variation at Glu-B3 and qualitative parameters show that cultivars with soft texture were completely lack of r3 band, whereas the presence of r2 band was quite evident in cultivars with soft texture.

In recent years, biological fertilizers have received special attention by scientists in sustainable and low input agriculture. In order to study the effects of arbuscular mycorrhizal fungi and free living nitrogen fixing bacteria on growth and photosynthesis characteristics of corn in conventional and ecological cropping systems, a field experiment was conducted during 2005-2007. A split plots arrangement based on randomized complete block design with three replications was used. Treatments consisted four cropping systems (high, medium, and low input conventional as well as ecological system) and four inoculations (mycorrhiza fungus, bacteria, dual inoculation (fungus plus bacteria), and noinoculation (control)), which were allocated to main plots and sub plots, respectively. Dry matter (DM), seed yield (SY), leaf area index (LAI) canopy temperature (CT), soil respiration rate (SRR), root length colonization percent (RLCP), specific root length (SRL), plant and soil N, P, and K content were measured. Results showed that the lowest CT existed in ecological cropping system. The same was observed for inoculants effect on CT. SRS and RLCP were not affected by cropping systems, but the effect of inoculants was significant, the highest SRS existed in dual inoculation. The highest SRL observed in fungus and bacterial inoculation. The effect of inoculants on plant P and K was not significant and the lowest plant N was observed in fungus inoculation. Correlation coefficients showed that, the strongest correlation obtained for DM and LAI, and between SRL and SY. The positive and significant correlation between RLCP and LAI, and between SRL and DM, emphasis that any factor increasing RLCP and SRL will increase LAI and DM, thereby, seed yield. Yield estimation model predicted that SY was determined by some variables such as LAI, CT, SRL. This study showed that utilization of low input conventional and ecological systems in combination with use of dual inoculation of arbuscular mycorrhizal fungus and free living nitrogen fixing bacteria could be a suitable alternative for high input conventional systems and chemical fertilizers.

In order to evaluate the interference influence of natural weed population on growth indices of corn an experiment in Randomized Complete Block design with 4 replications was conducted in 2006 at Ramin Agricultural and Natural Resources University, Mollasani, Ahwaz. Treatments included weedfree control of corn at three densities (4, 7 and 10 plant/m2) and weed-infested period to v9, v13 in any of plant populations (4, 7 and 10 plant/m2). Somewhat weeds interfere from emergence to the aforementioned stages of corn growth. Then weeds were controlled to harvest time. Meanwhile, one additional treatment was arranged as control plots for weed-infested (full season competition) with density (7 plant/m2, common plant density in Khouzestan). Results showed that, weeds caused significant reduction in corn dry matter, leaf area index, crop growth rate and relative growth rate. Meanwhile, excluding the early season growth, the maximum dry matter, leaf area index, crop growth rate and relative growth rate observed in weed-free (pure stands) treatments in all densities(4, 7 and 10 plant/m2). The maximum reduction rate of dry matter and leaf area index of corn to weed-infested (full season competition) treatment was concerned in 7 plant/m2 density. The minimum reduction rate of dry matter and leaf area index to weed–free occurred in 10 plant/m2 density.

Seedless berberis is one of the few crops which are cultured only in Iran and south khorasan. However, there has been no effort in the field of identification, polymorphism evaluation and study of genetic structure of seedless Berberis populations and its relative existing in Iran. In addition, despite the classical studies made based on botany and systematics around the world, there are still ambiguities and debates about the phylogenetic relationships within species existing in this family, mainly due to different efficiency of different methods. So in this paper- for the first time in Iran- morphological markers were used to evaluate variation and phylogenetic relationships among Berberis populations of khorasan provinces compared to data resulted from AFLP markers by means of Mantel correspondence test. The results showed that there is a low correlation between AFLP data and morphological markers. Since experimented morphological traits comprise about 90% of the traits existing in identification key of Flora Iranica and are often vegetative, week evaluation and correlation between AFLP data and morphological markers based on identification key can indicate low efficiency of identification key of Flora iranica for classification and phylogenetic consideration of berberis family. Therefore further molecular and morphological investigations aiming better understanding of the relationships between spieces and genera of Berberis family looks necessary.

Optimization of regeneration in lentil is necessary to improve this plant by novel methods. First stage of regeneration is efficient multiple shoot induction using proper explants. In this research, four explants of leaflet, stem, cotyledon without embryo axes and cotyledon with embryo axes were tested to determine the best explant. Probably effect of BAP in germination media of seedling tested on shoot induction of explants. There was comparison between effect of different level and combination of various cytokinins on multiple shoot induction. Effect of explant age and pH of media also tested on shoot induction. Results showed that, cotyledon with embryo axes is the best explant. Existence of BAP in germination media was very useful. There was highest shoot induction percentage (until to 96%) in MS media complemented with 7.5mM 2ip, 4mM Kin and 2 mM TDZ. Using this media produced more than 40 shoots per explant in some samples. Age of explant and pH of media was effective on multiple shoot induction. Results of primary research in gene transformation of lentil indicated efficient ability of this protocol to use in gene transformation.

To detect wild oat resistant to clodinafop-propargyl (Topik) in Khuzestan wheat fields, a seed bioassay study was conducted in Weed Science Laboratory of Ferdowsi University of Mashhad, College of Agriculture, in 2006. Forty five wild oat biotypes were collected from 7 cities of Khuzestan province including Ahvaz, Andimeshk, Shush, Shushtar, Ramhurmuz, Susangerd (Dashte-Azadegan), along with a susceptible biotype, from regions with no chemical control record. The study was carried out in three steps including determination of discriminating dose for susceptible biotype, screening wild oat biotype with discriminating dose, and dose-response experiment for suspected biotypes. In all experiments shoot length (% of control) in petri dish, 7 days after herbicide application was used as a plant growth index. According to the seed bioassay test, the discriminating dose for sensitive biotype was detected as 0.02 mg a.i. L-1. In the screening test with discriminating dose, 17 biotypes were determined as a suspected resistant. Our results showed that herbicide resistance is evolved in some wild oat biotypes in Khuzestan wheat fields.

Barley (Hordeum vulgare L.) is a model plant for genetical and physiological studies and has a high adaptability to different conditions. At seedling stage drought stress prevents the suitable establishment of plant. It is possible to categorize the genotypes into resistant and sensitive genotypes using physiological and morphological traits. The objective of this study was to identify resistant and sensitive genotypes to osmotic stress among 9 Iranian and European genotypes. Poly ethylene glycol (PEG) was used for simulating the drought stress at chamber. Genotypes were cultured at control and stress conditions. The leaf wilting percentage was recorded 3, 6, 9 and 12 days after PEG application. RWC and some morphological traits were 7 and 14 days after PEG treatment, respectively. The results showed a highly significant difference between two growth conditions. The differences among genotypes were significant. Fro all traits except the area under wilting progress curve, the sensitive index was calculated. The results showed that Nutans and Erectum are the most sensitive and Dari_83_6 and L.527 are the most tolerant genotypes to osmotic stress at seedling stage. Although EC_79_10 can be considered as tolerant based on the seedling morphological traits but it showed a significantly higher wilting than tolerant genotypes and so will be grouped as semi tolerant.

The effects of water deficit stress and nitrogen were studied on yield and vegetative characteristics of Calendula (Calendula officinalis L.). An experiment was conducted at Research Field of Islamic Azad University of Takestan branch in 2006. Field experiment was carried out by a split plot design based on completely randomized block design with 4 replications. treatments were three levels of stress as irrigation after 40, 80 and 120 mm water evaporation from evaporation pan, and consumption of 0, 30, 60 and 90 kg/ha nitrogen. The results indicated that water deficit stress had significant effect on plant and main stem height, number of lateral stem, flower weight to plant dry ratio, petal weight to flower dry ratio and flower yield (p£0.01). The plants had the highest main stem height, number of lateral stem, flower weight to plant dry ratio, petal weight to flower dry ratio and flower yield (2406 kg/ha) when irrigation after 40 mm evaporation from pan class A. Nitrogen had significant effect on plant and main stem height, number of lateral stem and flower yield. The highest plant height, main stem height, number of lateral stem and flower yield (1546kg/ha) were got by applying of 90 kg/ha nitrogen. Irrigation and nitrogen interactions effect were significant in lateral stem number and flower yield. It seems, applying of Nitrogen fertilization had not significant effect on morphological characteristics on Calendula in water deficit stress.

Cramb is an important medicinal and industrial plant which distribute in a vast area of Khorasan Razvi rangeland. A laboratory study was conducted to investigate the effect of different temperatures on seed germination of Crambe kotschyana in a randomized design with four replications of 25 seeds. Various constant temperatures (2, 5, 10, 15, 20, 25, 30, 35 and 40°C) were considered. The characteristics such as percentage of seed germination, rate of seed germination, the time of reaching 50% seed germination were recorded. The effect of temperature on rate and percentage of germination was significant. Maximum seed germination (100%) occurred in all temperatures except 2, 35 and 40°C. In All temperatures except of 2, 35 and 40°C, there was no significant difference in rate of seed germination. However, the highest rate of seed germination was obtained in 20°C. Based on linear regression between germination rate and temperature in both species, the cardinal temperatures: minimum (Tmin), optimum (To) and maximum (Tmax) were determined which were: 1.7, 18 and 43°C for Crambe abyssinsca, respectively.

In order to investigate the allelopathic effect of walnut leaf extract on germination characteristics of wheat, onion and Lactuca, a research was conducted at faculty of agriculture, Uremia University in 2007. In this experiment, the effects of different concentrations of walnut water leaf extract including control (distilled water), 2.5, 5 and 10% on germination characteristics on three plants: wheat, onion and Lactuca separately was studied in completely randomized design (CRD) with three replications. Increasing concentration of leaf extract lead to continuously decrease in germination percentage, germination rate (GR), time to reach 50% germination (T50), radical and plumule length and seedling fresh and dry weights. The most inhibition effect on germination percentage was observed in Lactuca. The most and the least decrease in germination rate, concerned to Lactuca and onion of 59.44 and 22.23 percentage, respectively. Also, the most inhibition effect on time to reach 50% germination was obtained in wheat. The most inhibition effect on steam and root length in wheat plant was resulted in 88.47 and 80.11 percentage in 10% concentration than the control, respectively. Greatest decrease in fresh and dry weight concerned to wheat because of its high sensitivity than other plants. Furthermore, onion showed the least sensitivity to juglan allelopathic substances.

In order to study the competitive relations of three wheat cultivars with different densities of wild oat, an experiment was conducted in factorial arrangment based on completely randomized block design in field of Abosaeed Agricultural School of Feizabad, with three replications. Experimental factors were consisted of three cultivars of wheat (Falat, Sepahan, Pishtaz) and five wild oat densities (0, 5, 10, 20, 40 plant/m2). Result showed that the the highest yield was obtained in weed free conditions for all wheat cultivars. Pishtaz showed superiority in respect to competition ability, growth characteristics and yield potential, compared to othere cultivars, so that in density of 40 plant/m2 of wild oat grain yield of wheat cultivars reduced about 44.66, 42.6 and 34.12 percent for Falat, Sepahan and Pishtaz, respectively. These differences was significant at P<0.01. The higher the wild oat density (20&40 plant/m2) the lowest vegetative and reproductive growth of wheat cultivars, specially in Falat. Finally results confirm that, wild oat can reduce grain yield and harvest index of wheat cultivars throughout its effect on productive tillers number, wheat leaf area index, plant height, 1000 seed weight and kernel number in spike. These competitive effects occurred during the growing season and reproductive period of wheat. The yield reduction was different and depended to morphological and competitive characteristics of each cultivar.

In order to evaluate phenological and morphological characteristics of cold tolerant chickpea germplasms, an experiment was carried out based on incomplete block design with 81 chickpea germplasms and three replications in 12th Oct. 2006 at Mashhad Ferdowsi University, Agricultural Station. These germplasms had been selected among 700 accessions from RSPS (Research Center for Plant Sciences) Seed Bank after some cold tolerance studies in 10 years. Irrigation was done three times, immediately after sowing, 20 days after that and at flowering stage. Before occurring of winter cold, type and stage of plant growth were measured. Also, phenological and morphological characteristics of germplasms including emergence, flowering and ripening, stage, plant height, branches number per plant and branches length per plant were measured. Based on results, there were significant differences among germplasms for all of the measured characteristics. The length of vegetative period (emergence to flowering stage) was more than 170 days for 57% of germplasms. Plant height for 27% of the germplasms was more than 46 cm. 11% of the germplasms had more than 26 branch per plant. Thus, it can be concluded that positive effects resulted from improving of phenological traits in fall sowing , caused for morphological and yield enhancement.

In order to evaluate of yield and yield components of cold tolerant chickpea germplasms, a trail was carried out based on incomplete block design with 81 chickpea germplasms and three replications in 12th Oct. 2006 at Mashhad Ferdowsi University, Agricultural Station. These germplasms had been selected among 700 accessions from RSPS (Research Center for Plant Sciences) Seed Bank after some cold tolerance studies in 10 years. Irrigation was done three times, immediately after sowing, 20 days after that and at flowering stage. Some characteristics including survival percent, yield components (pod numbers per plant, seed numbers per pod and 100 seed weight), seed yield, biological yield and harvest index were determined. Based on results, there were significant differences among germplasms for all of the measured characteristics. Survival percent for 40% of germplasms was more than 76%. Also, seed yield for 16% of germplasms was more than 150 kg/ha. There were positive and significant correlations between seed yield and survival percent (r= 0.47**), pod numbers per plant (r=033**), seed numbers per pod (r=0.33**) and 100 seed weight (r=0.20**). Thus, it can be concluded that positive effects resulted from improving of morphological and phenological traits and yield components of germplasms in fall sowing , have resulted in yield enhancement. Regarding to 480 kg/ha as average chickpea yield in Iran, an increase to 2.5 times can be expected by fall sowing of cold tolerant chickpea varieties.

In order to investigate the effect of water deficit and micro nutrition application on yield, yield component and water use efficiency in maize (KSC 704), a field experiment was carried out in the research station of Islamic Azad University- Arak Branch, Iran in 2007. This experiment was arranged in a split plot factorial based on complete randomized block design with four replicates. Main studied factors included four irrigation levels, irrigation equal crop water requirement, water deficit stress at eight- leaf stage (V8), stage of blister (R2) and grain filling in the main plot. Combined levels of selenium treatment (with and without) that applied two weeks before execution of water stress treatment at the rate of 20 g ha-1 and microelements (without and with) that was provided by specific fertilizer for maize called " biomin " which contains microelements of Fe, Zn, Cu, Mn, B, Mo and Mg in the form of foliar application at six-leaf stage and one week before tassling stage at the rate of 2 liter ha-1 were situated in sub plots. Results showed that significant different was found in yield, component yield, harvest index and water use efficiency under water deficit stress. The lowest grain yield belonged to plants under water deficit stress in grain filling stage. In this stage decreased grain yield by %33 as compared with control. Effect of selenium on yield and component yield non significant, but with using selenium increased yield and yield component. Interaction effect of water deficit stress and selenium was significant. A negative antagonistic interaction was found between selenium and microelements. Effect of compound treatments on measured parameters was significant on grain yield. Using of selenium and micro nutrition with water deficit stress at eight- leaf stage and grain filling increased yield, yield component and water use efficiency as compared without using this elements in water stress condition. In general, it was concluded that using selenium and microelements would be acceptable management practice under water stress.

During the recent years introduction of rapeseed in the oil seed production systems of Iran is promoted by the policy makers of agricultural sector because of special characteristics of this crop. In order to evaluate the production barriers of rapeseed and farmers tendency for this crop in Khorasan province, 220 rapeseed farmers were randomly selected and their attitudes were evaluated using previously designed questioners. The results showed that in average the producers were 43 years old and 75% of them had agricultural experience for up to 10 years however, the study year was the first rapeseed farming experience for 38% of selected farmers. Yields above 2 t ha-1 were harvested by 31% of producers while the attained yield for 25% of farmers was lower than 1 t ha-1. Based on the results only 30% of farmers were satisfied by the harvested yield and 36% of them showed tendency to continue rapeseed production. Low water requirement of rapeseed compared to the alternative crops was considered as the main beneficial characteristic and chilling risk was pointed as the main barrier for rapeseed production over the province. Farmers were satisfied by the extension and technical services however, lack of harvesting machinery and trading complexities were also important problems. Based on the results it seems that introduction of new cold tolerant rapeseed cultivars with higher yield potential and improvement of the seed price are the main priorities for making rapeseed competitive with alternative winter crops such as wheat and barley.

In other to study effects of different levels of NaCl (0, 10, 15, 20 dSm-1) on growth characteristicts and physiological aspects of modder (Rubia tincforum L.) two separate examinations with a completely randomized design and four replications were conducted. In the first experiment the effects of different levels of salinity (o, 5, 10, 15, 20, 25, 30, 35, dSm-1) on rate and percentage of seed germination and length of seedlings were measured. Results showed that thershold level at which nearly 50% of seeds did not germinate was 10 dSm-1. In the other examination, salinity levels were imposed by applying solutions of NaCl in Hogland medium circulated in a sand culture closed system. Criteria such as chlorophyll meter number (SPAD readings), stomatal resistance, specific leaf weight, leaf area, stem/root length ratio were measured or calculated. Althought results showed that by increasing salinity stomatal resistance and specific leaf weight was reduced, the amount of the other characteristics was reduced.

Drought tolerance is a quantitative trait and immeasurable directly. Hence, for assessing drought tolerance related characters should be measured. Drought related characters such as root architecture and water use efficiency are quantitative traits and their phenotypic assessment, especially under filed conditions, is difficult. Consequently marker assisted selection is a superior tool for overcoming this problem. At this research genetic control of drought related characters was assessed using QTL analysis method. A set of 220 double haploid lines, derived from Kukri (drought sensitive) and RAC875 (drought tolerant), were used. Overall, 35 QTL on 11 chromosomes were identified. Ten QTL had R2>10. 63% of identified QTLs were located on B genome that shows the substance of this genome in drought tolerance. Root system and water use efficiency are two imperative drought tolerant mechanisms. But their phenotypic assessment under drought condition is either difficult or impossible. Hence these two worthwhile mechanisms are ignored at breeding programs. At this research 3 QTLs on chromosomes 1B, 5A and 5B were identified for root number that explained 39.7 percent of phenotypic variations. Also 3 QTLs on chromosomes 1B, 4B and 6D were responsible for genetic control of water use efficiency and explained 30 percent of phenotypic variation. Root number and water use efficiency have genotypic correlation, the genotypes with more root had more water use efficiency. Leaf width is the most important related character for early vigor. Five QTLs on chromosomes 2B, 2D, 3D, 5A and 6A were identified for leaf width that explained 41.6 percent of phenotypic variations. Selecting genotypes, using Marker assisted selection (MAS), for favorable alleles that has been identified in this study such as Gwm0304b and Barc0256 may allow to improve drought tolerant mechanisms, consequently yield at drought prone environments.

In order to study the yield and yield components in intercropping of bean and sweet basil and evaluating effect of intercropping on weed control, an experiment was conducted at the Agricultural Research Station, Ferdowsi University of Mashhad in the growing season of the year 2008. The experimental treatments were: 1- sole crop of bean 2- sole crop of sweet basil 3- strip intercropping of bean and sweet basil (four row bean and two row sweet basil) 4- strip intercropping of bean and sweet basil (two row sweet basil and four row bean) 5- row intercropping of bean and sweet basil were with and without weed control. For this purpose a Complete Randomized Block design with 3 replications was used. Results showed that economic and biologic yield of bean, number of pods and number of seeds per plant were affected by different treatments and that were no significant difference in number of seeds per pod, 100-seed weight and harvest index in bean. Number of inflorescences, number of nodes per plant, number of seeds per plant, number of branches, economic and biologic yield in sweet basil also affected by different treatments but there were no significant difference in the 1000-seeds weight and harvest index of sweet basil. Lowest dry mater (DM) of weed was obtained in sole crop sweet basil and strip intercropping with four rows sweet basil and the highest dry mater of weed was in sole crop of bean. The highest Leaf area index (LAI) in bean was obtained in sole crop with weed control and the highest leaf area index in sweet basil was in row intercropping with weed control. The highest Land Equivalent Ratio (LER) was obtained in row intercropping with weed control.

In order to determine the relative shares of different photosynthetic wheat parts for grain dry matter accumulation and their sink limitation, this study was conducted in from of a split plot experiment with complete randomized block design with three replications in Ahvaz Agricultural Research Station in 2001-2002 growing season .In this study, 10 wheat cultivars were considered as main factor and 4 phenotypic components manipulation treatment including awns removing of the whole spikes (-A), flag leaf removing (-FL) ,removing of leaves under flag leaf (-L) and spike covering (CO) were considered as sub factors . Means comparisons for phenotypic components manipulation factor showed that spike photosynthesis had highest relative shares in grain filling (15.93%). Also, 13.9, 12.1 and 11.9 percent of mean seed dry matter relative share belonged to flag leaf, leaves under flag leaf and awns respectively. Evaluation of sink limitation of studied cultivars showed that there was no sink limitation in these cultivars. CIMMYT cross line and Star cultivar had greatest sink limitation then other cultivars, although Dove and Chamran cultivars had lowest.

In order to evaluate physiological and morphological characteristics of 9 cold tolerant spring cultivars of rapeseed at different planting dates from different Brassica species i.e. B. napus, B.rapa, B. juncea an experiment was conducted with three sowing dates (27th September, 27th October, 24th December) in Mashhad. The layout of experiment was randomized complete block design with four replications. Rapeseed cultivars consisted of Hyola401, Hyola330, Option500, RGS003, Sarigol, Zarfam, GoldRush, ParkLand and Bp.18. Traits under investigation were, seed yield, number of branches per plant, number of pods per plant, number of grain per pods and 1000 grain-weight. Results showed that sowing dates and cultivars had a significant effect on all traits. However, sowing date×cultivar interaction had only significant effect on yield, grain number per pod and 1000 grain-weight. First sowing date had the most seed yield for cultivars with the average of 2338.9 kg ha-1. GoldRush and Hyola401 with the average of 3000 kg ha-1 had the highest yield in first sowing date. For the second and third sowing dates, the highest yield was belonged to GoldRush and Hyola330, respectively. Hyola hybrids showed the best adaptation in various experimental conditions. In addition, because of their vigorous growth habit, they showed very good potential for delayed planting.

Crop cultivars development with high grain yield is the principle goal in bread wheat. In spite of that, the efficiency of each breeding program mainly depends on quality, direction and magnitude of the association between grain yield with other traits involved in grain yield formation and the relative importance of them. For this purpose, twelve cultivars and landraces of bread wheat (Triticum aestivum L.) were evaluated for seventeen characters. The result of simple correlation coefficient analysis indicated a significant positive association between grain yield with harvest index, biological yield, the number of spike per square meter and negative association with time to heading. Association between grain yield with harvest index and biological yield were also obtained through regression analysis using stepwise method. By using factor analysis, seventeen variables were defined in four factors explaining 84 percent of total variations. The first factor considered as yield factor confirmed the effective role of harvest index and biological yield each on grain yield again. The second factor considered as yield components factor, indicated negative correlation between the number of spike with kernel’s characteristics in each spike namely kernel weight and kernel number, which was in accordance with the results which has obtained from simple correlation coefficient analysis. Path analysis indicated direct positive effect of biological yield, the number of spike per square meter, the number of kernel per spike, plant height and spike length each on grain yield. Overall, our observations showed the harvest index and biological yield as important traits in selection of high yielding bread wheat varieties. Furthermore, the number of spike per square meter was the most important yield component and plant height was important morphological trait determining the grain yield, seemingly, selection of these two traits may contribute to increase in grain yield. Also, the reversed reciprocal effect of the number of kernel per spike on other traits involved in grain yield, explained limited success in improvement of bread wheat that has been pointed out by other researchers.

Flowering in saffron take places in two separate stages, both triggered by temperature as the main driving force. Based on the existing evidence about the temperature rise due to global warming it seems that flowering behaviour of saffron could be affected by future climate change in production areas. In order to study the flowering responses of saffron to temperature rise a model for simulation of flowering behaviour was developed. Using this model development rate and duration at each flowering stage in response to 0.5, 1.0, 1.5 and 2°C increases in mean daily temperature above the current records was simulated. In the model development rate (DR) is calculated based on maximum DR at optimum temperature (DRm1, DRm2) multiplied by a specific temperature function for each stage (ft1, ft2). Duration of each flowering stage was then estimated as the reciprocal of the calculated development rates. The value of DRm1 and ft1 was estimated from evidences in the literature at optimum temperature of 23-25°C. DRm2 and ft2 was calculated by fitting 5-parameter b function to the saffron development rate and temperature data were collected from farmers fields located in production areas. Using these data the minimum, optimum and maximum temperatures for the second stage of flowering was estimated as 15.5, 18.0 and 22.5°C, respectively with maximum development rate of 0.0289 day-1. Simulation results indicated that the effect of temperature rise on reducing development rate was similar for both flowering stages and hence flowering duration will be increased by 32 to 38 days per 1°C increase in mean daily temperature. Therefore, temperature rise by 1.5-2.0°C due to climate change results in postponing time of flower emergence until early to late December in the main saffron production regions of Khorasan provinces.

In order to investigate the response of yield and yield component of three maize hybrids on seven plant densities, an experiment was conducted during 2006 growing season in Mashhad, Iran. Three maize hybrids including late maturity maize (704), medium maturity maize (504) and early maturity maize (260) and seven plant densities including D1 = 3, D2= 5, D3 = 7, D4 = 9, D5 = 11, D6 = 13 and D7 = 15 plants m-2 were compared in a strip plots design with three replications. The result of this study showed the radiation use efficiency increased in proportion to an increase in the plant density: the late maturity variety of 15 plants m-2 (1.103 g MJ-1), the medium maturity of 15 plants m-2 (1.214 g MJ-1) and early maturity of 15 plants m-2. Density factor had significant effect on the number of row of seed per each ear, the number of seed per each ear, 100 seed weight and seed weight per plant. There was significant difference among ear diameter, ear length, number of seed row on each ear, number of seed per each ear, seed weight per each plant, 100 seed weights and weight of dry cob per each ear. The highest grain yield were obtained in third plant density (D3) for late maturity hybrid (11334 kg ha-1), in fourth plant density (D4) for medium maturity hybrid (10937 kg ha-1) and in sixth plant density (D6) for early maturity hybrid (7591 kg ha-1). When the plant density was increased more than optimum rang of density, biology yield increased and seed yield decreased. The results demonstrated that optimum yield was depended on radiation use efficiency, plant growth types and density. Our results showed that late maturity maize compared to early maturity hybrids need less density.

In order to evaluate intercropping of corn and bean, an experiment was carried out in the research field of Faculty of Agriculture, Ferdowsi University of Mashhad in the growing season of 2006-2007. The trial was arranged as a complete randomized block design with three replications. For this purpose, row replacement series was used. Treatments included different combinations of bean and corn: 25:75, 50:50, 75:25 and their monoculture. Results indicated that combination of 50 percent of both crops in an alternate manner was superior to all other combinations. Land equivalent ratio (LER) for yield and dry matter production was more than 1 in this treatment. In all combinations of intercropping, changes of seed yield and also dry matter yield was in favorer of corn and consequently not in favored of bean. As corn density increased in intercropping, seed yield, dry matter yield, harvest index, number of ears per plant, number of seeds per ear and 1000-seed weight were increased (p<0/05). By further increasing bean density in intercropping seed yield, dry matter yield, number of pods per plant, number of seeds per pod and harvest index in bean were increased (p<0.05).

A field experiment was conducted to evaluate the effect of nitrogen and cycocel (2-chloroethyl trimethyl ammonium chloride), CCC application on yield and yield components of two oilseed rape cultivars (cv. Talaye and Likord). The study was conducted under Badjgah (52° 46’ N, 28° 50’ E) agroclimatic conditions at the college of Agriculture, Shiraz University, Shiraz, Iran during 2004-5. The design of the experiment was a split-split plot with four replicates. There were two cultivars (Talaye and Likord) in main plots, four nitrogen levels (0, 50, 100, 200kg/ha) in sub-plots and three growth retardant rates (0, 1.4, 2.8 CCC L/ha) in sub-sub plots. The results showed that the highest seed yield in Talaye and Likord was achieved when 200 kg N/ha was used. Increase in nitrogen application was associated with increased dry matter produced, and number of siliques/plant. Number of seeds per silique, and mean seed weight were among the most stable components of yield and did not show any significant changes. Likord oil and protein percentage was highest at 100 kg N/ha and is recommended to be followed up in future investigations. Application of cycocel at 2.8 L/ha enhanced the number of siliques/plant, seed yield and dry matter produced. In addition, cycocel application at 200 kg N/ha increased the seed yield/m2. Cycocel application at the rate of 2.8 L/ha and 200 kg N/ha in both cultivars might be recommended for similar agroclimatic conditions.

In order to evaluate the effects of different organic and biological fertilizers on seed yield, yield components and essential oil content of Fennel an experiment was conducted in a completely randomized block design with three replications. The experimental treatments were 4 biological fertilizers and all combinations (1- control (without any fertilizer), 2- bacterial strain Pseudomonas putida, 3- bacterial strain Azotobacter chroococcum, 4- compost, 5- vermicompost, 6- Ps. putida + A. chroococcum, 7- Ps. putida + compost, 8- Ps. putida + vermicompost, 9- A. chroococcum + compost, 10- A. chroococcum + vermicompost, 11- compost + vermicompost. There were significant differences between different treatment in terms of plant height, number of main and lateral branch per plant, number of umbelest per umbel, number of seed per umbel, harvest index, seed yield, biological yield, essential oil yield, seed weight per plant and number of seed per umbelest. The differences between different treatments were not significant in terms of 1000-seed weight and seed weight per umbel. Result also indicated that the highest plant height (86.83 cm) was obtained in A. chroococcum + vermicompost treatment. Compost + vermicompost treatment had the highest umbel per plant (30 umbel), 1000-seed weight (4.3 g), biological yield (5444 kg/ha), essential oil yield (29.98 L/ha) and seed yield (1059 kg/ha) compared with other treatments. The highest and the lowest harvest index were observed in control and vermicompost + Azotobacter treatments, respectively.

Demissum differentials are important for pathogen isolates identification. Recent studies show Ma.R9 contains R2 and R3 or homologues of the genes. This genotype has a high resistance against different isolates in the world. Candidate gene approach applied to isolate and cloning of these homologues in this genotype. Phylogenetic clades drawn and expression assay was done by coinfiltration in N. benthamiana. Result revealed this genotype contain R3a and also functional R2 like gene. Alignment of R2 gene against R2-like in amino acids level showed completely conserved residues in LRR region. Presence of more than one gene could be the reason of resistance against different isolates. These results confirm high efficiency of candidate cloning approach and effector genomics as new approaches.

In order to study the effect of plant density and supplemental irrigation on yield، yield components, and light interception canopy of three chickpea varieties in dry farming condition، an experiment was conducted in Khoramabad Agricultural Research Station during 2005. The experimental design was split split plot laid out RCBD with four replications. Three dry farming levels (rainfed, dry farming supplemental irrigation at 50% flowering stage and dry farming supplemental irrigation at during filling pods period), three varieties (Azad, Arman and Greet) and four plant density (30, 42, 54, 66 plants/m2) were randomized to the main plot, sub plot and sub-sub plot units respectively. The results showed that supplemental irrigation lead to increased biological yield (49%), grain yield (54%), plant pod number (43%), and canopy light interception (55%) in comparison to rainfed condition. The most grain yield (1388 kg/ha) and biological yield (3823 kg/ha) were obtained from crop density of 66 plants/m2. Chickpea canopy light interception increased as crop density increased; lowest light transition was related to crop densities of 54 and 66 plants/m2.

In this study, a linkage map of 117 AFLP markers was constructed in an F2 population derived from a cross between two Iranian rice varieties, Domsephid and Gerdeh. This map used for identification of the QTLs controlling yield in F2. Average grain yield in parents Gerdeh and Domsephid were 43.25 and 31.55 g/plant respectively, and t-test showed significant difference (P<0.01) between two parents. Genotypes were determined for F2 individuals using 117 AFLP markers. The linkage map of the population was generated with Map Manager V2.6.5. Map length was 1212 cM with an average interval size of 11.88 cM. QTLs analysis were carried out to determine the relationship between marker genotypes and trait values in F2 individuals using simple interval mapping (SIM) and composite interval mapping (CIM). In F2 population, one QTL associated with yield was determined on linkage group 2. Phenotypic variation associated with this QTL and its additive effect was 8.3% and 4.74 gr, respectively. In this QTL, alleles from Gerdeh increased grain yield.

In order to evaluate the effect of animal manure on Ajowan (Carum copticum) and Fenugreek (Trigonella foenum-graecum) different intercropping, an experiment was conducted as split plot on the basis of complete randomized block with three replications in 2005. For this reason four levels of animal manure (15, 20, 25, 30 tons/ha) was allocated to the main plots and different intercropping of Ajowan and Fenugreek at 5 levels in subplots (A: pure stand of Ajowan, B: pure stand of Fenugreek, C: single-row intercropping of Ajowan and Fenugreek, D: double-row intercropping of Ajowan and Fenugreek, E: triple-row intercropping of Ajowan and Fenugreek). Results showed that Ajowan leaf area index (LAI) and crop growth rate (CGR) in double-row intercropping, and dry matter (DM) accumulation in triple-row intercropping were highest, while for Fenugreek triple-row intercropping showed the highest LAI and CGR and also single-row intercropping had the highest DM. In Ajowan the highest DM accumulation was obtained with 30 ton/ha animal manure, while the highest LAI and CGR was obtained with 20 ton/ha. Howevere, in Fenugreek the highest values for these parameters were obtained in 25 ton/ha.

Long term weather data including temperature and radiation in Northern, Razavi and Southern Khorasan provinces were collected and used for agroecological zonation of wheat over the whole province. Weather data after spatial interpolation between stations and generation of daily values were used as inputs of a model for simulation of wheat growth and yield. The WOFOST model that showed acceptable performance during validation for predicting yield and development stages of wheat cultivars under favourable growth conditions, was used for estimation of potential (climatic) yield of wheat. The results showed that in spite of inter annual variations, mean potential yield of wheat was 6.2, 6.9 and 4.8 t ha-1 for Northern, Razavi and Southern Khorasan provinces, respectively. Actual wheat yield (harvestable yield) during a 10-year period from 1375 to 1385 was calculated as the average of the whole period and mean of the last 3 years of time series in each province. On this basis yield gap was estimated as the difference between potential and actual wheat yield. A regional yield factor was also calculated from the ratio of actual: potential yields. Yield data was stored in a GIS package and zonation maps were produced. Results indicated that mean actual wheat yield during the 3-year period of 1383-1385 compared to the 10-year period of 1375-1385 was increased by 28, 34 and 30% in Northern, Razavi and Southern Khorasan provinces, respectively which could be mainly due to improved management practices and introducing new cultivars. However, a relatively high yield gap of 3.7, 4.3 and 3.8 t ha-1 was estimated for Northern, Razavi and Southern Khorasan provinces, respectively. Regions with higher yield potential showed a higher yield gap and regional yield factor of wheat in Razavai and Southern Khoransan provinces with the highest and the lowest yield potentials was estimated as 0.37 and 0.42, respectively. During the period of 1383-85 in all 3 provinces the actual yield reached to the 50% of the potential yield indicating that the yield gap of wheat has been bridged due to improved management practices.

In order to determine freezing tolerance of 10 rapeseed (Brassica napus L.) cultivars including Zarfam, Licord, Elit, SLMO46,Okapi, Symbol, Calvert, Opera, Ebonit and Alis, a green house experiment was carried out at the College of Agriculture, Ferdowsi University of Mashhad. In a two-replicate RCBD split factorial experiment two levels of acclimation ( acclimated vs no acclimated) served as mainplots and a combination of five cold levels (0, -4, -8, -12 and -16°C) and the 10 genotypes served as subplots. Plants were kept until 3-5 leaf stage in greenhouse condition with 23/16 ± 2°C (day/night) and natural photoperiod. Then, the plants of non-acclimation treatment were frozen immediately and for acclimation treatment after three weeks that put them under acclimation freezing were done. Survival percentage, leaf area, SPAD reading, dry weight, (LT50)1 and (RDMT50)1 were determined after 3 weeks. Survival percentage after freezing was different in cultivars (P<0.01). Calvert, Symbol and Zarfam cultivars had the highest (77, 76 & 75) and Opera cultivar showed the lowest (63) survival percentage, respectively. Cultivars were different in leaf area, dry weight and LT50. The most freezing damage on the plant was absorbed at the lower than -4°C temperatures. Although acclimation decreased the freezing effects on the most characteristics. In according to the good correlation between LT50, SPAD reading, and LT50 with survival percentage, it seems that for evaluation of freezing tolerance in rapeseed using, the LT50 and SPAD reading may be useful.