Iranian Journal of Field Crop Science
Year:2009 | Volume:40 | Issue:2|Papers Count:24

A field study was conducted at the College of Agriculture, Shiraz University, Shiraz, Iran to evaluate the effect of different crop residue and nitrogen rates on yield and yield components of two dryland wheat (Triticum aestivum L.) cultivars. The experiment was conducted as a strip split plot with four replications. Vertical plots included two dryland current wheat cultivars (Azar2 and Nicknejad), while the horizontal plots constituting crop residue rates (0.500 and 1000 kgha-1) and sub-plots the three N rate (0.35, and 70 kg N ha-1) treatments. Results indicated that when crop residue completely returned to the soil (100 %), N return rates should be proportional to residue rate. Fertile spike No. per plant, grains per spike, grains per plant and 1000-grain weight significantly increased (p<%l) with increased N and residue rates in both cultivars. When the crop residue completely applied and N rate was suitable and proportional with crop residue rate, better infiltration might have promoted soil moisture conservation. When the crop residue was completely returned to the soil, but N rates not adequate and proportional with crop residue, yield components significantly diminished in either one of the cultivars. The highest grain yields were obtained from 1000 kg ha-1 of residue, and 70 kg of N ha-1 in Azar2. Azar2 had a significantly higher grain yield than Nicknejad variety. The correlation coefficients between grain yield and spike No. per m-2, grains per spike, grains per plant, biological yield as well as harvest index were observed as positive.

To study the mixing rates effects of barley (Hordeum vulgare L.) and chickpea (desi type) (Cicer ariethinum L.) on forage production under dryland conditions, a field experiment was conducted at Agricultural Research Station of University of Tehran (Karaj campus) during the 2003 - 2004 growing season. The 11 Treatments of this experiment were statistically compared based on a Randomized Complete Block Design of three replications. Experimental treatments were arranged as a factorial of sowing density levels of chickpea (100%, 75% and 50% of pure stand) and barley (100%, 75% and 50% of pure stand). Also two additional treatments of chickpea and barley sole cropping were established as control. Barley grain (Valfajr cultivar) and chickpea (4322 ecotype) were simoultaniously planted on 20th December, green forage being harvested on 10th May (next year). No manure or irrigation was applied in this experiment (dryland system adopted). Forage was harvested taking into account chickpea phenology (early flowering stage). Barley was the dominant plant in all the mixed treatments. Results showed that forage yield of chickpea and barley was significantly affected by mixing rate (P<0.01). There was no significant difference among treatments including 100% chickpea for chickpea yield. A similar pattern was observed for barley grain yield. The highest forage yield of 2981 Kg/1m was obtained for chickpea 100+barley100 intercrop treatment. Forage quality investigation showed that all qualitative traits except Water Soluble Carbohydrates (WSC), were affected by mixing rate. Although the highest protein yield (358.5 Kg/ha) was earned from Chickpea50+Barley50 treatment, there was no significant difference observed with Chickpea100+Barley100 treatment (318.4 Kg/ha). Meanwhile, introducing chickpea into barley cropping system augmented forage ash as well as crude fiber.

The objective of this research was to study genotypexenvironment interaction and to evaluate stability analysis of grain yield in chickpea genotypes under rainfed condition. Experimental material was comprised of 17 genotypes with the experiments carried out in RCBD of four replications at Kermanshah, Lorestan, Ham, Gachsaran and Gorgan Research Stations during the two years of 2003-2004. The results of combined analysis showed that yearxlocation, genotypesxlocation and yearxlocationxgenotypes were significant. Different stability analysis methods employed for assessing yield stability. Using environmental coefficient of variation, it was (CVi) indicated that genotypes no. 1,7, 13, 15 and 17 with high yielding and less variations may be identified as stable genotypes. Through Rank Sum of Method (RSM) it was found that genotypes number 7, 13 and 5 were the most stable lines. In addition, results of stability analysis on grain yield (using simultaneous selection for yield and stability as well as Shokla variance (si2) showed that genotype no.13 was the most stable genotype. Stability analysis determined through AMMI stability value (ASV) method showed that genotype no.13 (FLIP 97- 114) was the most stable one. All in all and based on different stability analysis methods it was shown that genotype no. 13 was the most stable genotype. The results of different stability parameters were found to be similar for the selected genotypes. But AMMI stability value (ASV) was found to be a more valuable and practical approach to stability analysis in compare to others, for ASV parameter explained %76 of the genotype x environment sum of squares.

A greenhouse research work was conducted to study the patterns of Na+ and K+ distribution in root, stem and leaf during three growth stages of four Iranian alfalfa ecotypes and to find correlation between these patterns and plant salt tolerance. Treatments were replicated three times in a factorial experiment of a completely randomized block design. Based on the threshold of salt tolerance in alfalfa, three levels of salinity (control, 7 & 12 dS/m), were employed as salt stress treatments. The dry weight of roots, stems and leaves were determined and their Na+ and K+ concentrations measured. K+ concentration was reduced by increasing salinity, while Na+ concentration increased. The yield response of alfalfa ecotypes to the salinity treatments varied in various growth stages of the plant. At seedling stage, Shirazi ecotype and during the second and third vegetative cuts, Hamedani ecotype showed the highest level of phytomass. The highest concentration of K+ in seedling stage was observed in Shirazi ecotype and in the second and third vegetative cuts, this was observed in Hamedani ecotype. When the concentration of Na+ in tissues exceeded the toxic threshold, the hazardous effects of this ion substantially influenced the ecotypes, yields. In both levels of salinity, concentrations of Na+ and K+ diminished strating from root towards shoot in the studied ecotypes. Therefore, Na+ concentration in root was more than those in stem and leaf under saline conditions, which could be attributed to the remobilization of Na+ from the shoot to the root. The lowest rates of Na+ in the studied plant parts at the second and third cuts, were also observed in leaves. The critical role of the leaves in photosynthesis and plant survival may have caused a prevention of Na+ entry into the leaves via various mechanisms. This however was associated with a considerable increase in the ion's concentration in shoot at the second and third cuts, as compared to root. So, regarding the importance of physiological processes in providing the salinity tolerance mechanisms, a study of other physiological characteristics which influence salt tolerance such as carbohydrates and nitrogen translocation from root to the shoot can have their special importance in future studies.

Nitrogen and phosphorus are two of the essential nutrients that promote plants' growth and yield. Deficiency of these nutrients in soil is usually compensated through application of chemical fertilizers. Chemical fertilizers on the other hand have detrimental effects on environment in addition to decreasing quality of agricultural products. The present study was conducted to evaluate the effect of an application of azotobacter and mycorrhiza as biofertilizer along with phosphorus (super phosphate) as the chemical fertilizer. The effects of the three factors, namely: azotobacter (inoculated and not inoculated), mycorrhiza (inoculated and not inoculated) and phosphorus (0, 50, 100 and 200 kg/ha) was evaluated through a factorial experiment of completely randomized block design of three replications in Central Province (Arak) Research Center of Agriculture and Natural Resources. The main and intraction effects of the three mentioned factors for number of kernels per row, number of kernels rows/ear, number of kernel per ear, ear, and dry matter weight showed that mycorrhiza symbiosis enhanced absorption of mineral elements, and as corrected the plant's nutrition. Azotobacter also caused the fixation of biological nitrogen and production of metabolities that significantly affected the mentioned traits. The interaction of micorrhiza and 100 kg/ha of phosphorus had the most positive effects on the above traits. The results also indicated that, although every factor had its own positive effect on com growth, yield, and other traits, but their interaction effects were more noticeable. The study also indicated that application of mycorrhiza along with azotobacter, not only decreased the demand for phosphorus (amount of only 100 kg/ha), but also improved yield and crop quality.

Response of primed (osmopriming) vs non primed Panicum miliaceum, Panicum antidotale and Setaria ita/ica seeds to low temperature, drought and salt stresses were studied. Seeds were primed under -12 bar of water potential of priming solutions for a 7 day priming duration at 20°/30° (12/12 hours), IS° and 25°C of priming temperatures respectively. The primed and non primed seeds were exposed to low temperature, drought and salt stress conditions to observe the results of seed priming. Seeds were evaluated after being exposed to drought (-4,-8,-12 and -16 bar, PEG 6000), salt (-4,-8,-12 and -16 bar, NaCl) and low temperature (10, 15,20 and 25°C) stresses during their germination process. Either one of the drought or salt stresses exhibited similar stress effects on the rate and percentage of seed germination. Rate and percentage of seed germination was significantly reduced at each level of drought and salt stress as against its previous level. At each level, the primed seeds were of higher values in these traits compared with the non primed seeds. Lowering germination temperature to 15°C reduced seed germination rate and percentage in either of the seed treatments. This temperature regime also caused a significant reduction in root and shoot lengths. Primed seeds germinated faster and to a higher extent significant than the non primed ones.

To study the effects of plant density and time of weeding on the growth, yield components and grain yield of autumn chickpea, an experiment was conducted during 2005-2006 at Agricultural Research Station of Khorram-abad. Five weeding regimes (no weeding, weeding in three, five, seven weeks after tertiary branching and continuous weeding during the whole growing season) along with four plant densities (20, 40, 60 and 80 plants/m2) constituted a factorial randomized complete block design experiment of three replications. The results showed that delay in weeding from five to seven weeks after tertiary branching reduced the number of pods per plant, number of grains per pod as well as grain yield. The highest number of pods per plant, number of grains per pod and grain yield was obtained by weeding during the whole growing season, but the difference of yield in this treatment with that in the treatment of weeding five weeks following tertiary branching was not significant. Increase in plant density led to significant decrease in the number of primary and secondary branches, number of pods per plant and a significant increase in grain yield as well. It was 80 plants/m2 which yielded the highest grain, showing no significant difference with 40 and 60 plants/m2 treatments. The results indicated that planting autumn chickpea at 40 plants/m2 along with weeding in five weeks following tertiary branching could be appropriate for chickpea production under conditions similar to those in this experiment.

Diversity of durum wheat (Triticum turgidum ssp. durum) gennplasm was evaluated using simple sequence repeat (SSR) markers. One hundred and forty durum wheat genotypes of diverse origin (belonging to ten countries) were assessed using 48 selected SSRs with whole genome coverage. A total of 245 allelic variants were detected at 37 polymorphic SSR loci, ranging from two to seventeen per locus with an average of 6.9. The polymorphic information content (PIC) values of the loci ranged from 0.007 (Xgwm 274) to 0.799 (Xgwm 427). Genetic similarities were assessed through simple matching method, ranging from 0.583 (two genotypes from Kermanshah and Khorram Abad, Iran) to 0.94 (two genotypes from Ahvaz/IRAN). Complete cluster analysis method based on genetic similarity estimates produced two main groupings. The results revealed a meaningful relationship between genetic diversity and geographical regions. Separate grouping of Iranian vs foreign germplasm indicates the different genetic origin in these genotypes. A wide range of genomic diversity was observed among all the genotypes, proving them to be prime candidates for selective breeding for specific traits and a broadening of the genetic base.

Tritipyrum (2n=6x=42; AABBEbEb) is a new synthetic allohexaploid created through crossing durum wheat (2n=4x=28; AABB) and Thinopyrum bessarabicum (2n=2x=14; EbEb) and subsequently doubling the hybrid plant chromosomes. Secondary Tritipyrum is referred to the progenies of wheat and Tritipyrum crosses, obtained during segregating generations. The study of chromosomal constitution and fertility is very important in the assessment of hybrids derived fi:om wheat and wild relative crosses. Navid cuItivar of bread wheat (AABBDD; 2n=6x=42) was crossed with Tritipyrum (AABBEbEb; 2n=6x=42) the FI progenies being produced. F2 seeds were obtained by selfmg Fl plants and their chromosome number determined. The F2 plants possessing 42 chromosomes were selected for the study of their meiotic behavior. In spite of high chromosomal stability and fertility of the parents (wheat and Tritipyrum), these characteristics in F2 plants were observed as low probably due to the different chromosomal compositions and a lack of chromosome homology of D and Eb genomes and consequently the formation of univalents in pollen mother cells of F2 plants. The results of meiotic analysis of F2 plants confirmed the accessibility of different chromosomal composition and the production of either the addition or substitution lines in the progenies of segregating generations.

To evaluate the effects of accelerated aging and cold stress on seed germination and seedling growth indices in five oilseed rape cultivars (Hyola330, Hyola401, Hyola420, Syn3 and Pr401/15E), an experiment was carried out in a completely randomized design of three replications. Results indicated that the cultivars were significantly different in germination percentage, seed vigour, germination rate and seedling length under standard germination, cold stress and accelerated aging conditions. The cultivars Hyola401, Pr40l/15E and Syn-3 in standard germination, Hyola401 in cold test and Pr401/15E and Syn-3 in accelerated aging test exhibited the highest germination percentages. Furthermore, Hyola420 had the lowest germination percentage in all the 3 tests. The cultivars were different for seedling length, seed vigour index and germination rate in different tests, so that Pr401/15E, in standard germination and accelerated aging test, and Syn-3, in cold test, had the highest seedling lengths. Moreover, Pr401/15E in standard germination test, Syn-3 and Hyola401 in cold test and Hyola401, and Pr401/15E in accelerated aging test, bore the highest seed vigour index. As for germination rate, Pr401/15E, Hyola401 and Syn-3 carried the highest values in standard germination, cold and accelerated aging tests, respectively. In total, evaluation of the germination indices under stress conditions indicated that the seeds of high vigour were less affected by cold stress and accelerated aging tests, the difference between their germination indices under nonnal and under stress conditions being low. Furthermore, accelerated aging decreased canola seed vigour more than did cold stress. This indicates that canola seeds lose their quality in high temperatures more rapidly than they do at low ones, so seed vigour would strongly decrease if seeds stored in unsuitable conditions of high temperature and moisture. Therefore, proper storage conditions of canola seeds are important before sowing of the seeds next year.

Production of high yielding hybrid cultivars is among the main objectives of breeding programs in sunflower and on evaluation of the combining ability of the inbred lines necessary to select for the appropriate parental lines for production of hybrid cultivars. This study was conducted to investigate the general and specific combining ability and the mode of inheritance for agronomic and seed quality traits in some inbred lines of sunflower. Nine inbred lines of sunflower were each crossed with three male sterile inbred lines and then their hybrids (27 hybrids) evaluated for agronomic and seed quality traits. The data were analyzed based on the factorial model (Design II of Comstock and Rabinson) in a randomized complete block design of two replications. The results indicated that the additive genetic effects were more important than the non-additive effects of genes in the genetic control of days to flowering, days to maturity and seed oil content. The specific combining ability values for days to maturity and seed oil content varied from -3.67 to 4.50 days and from -2.89 to 2.42%, respectively. Both additive and non-additive effects of genes were important in inheritance of plant height, head diameter, 1000-seed weight, seed and oil yields with the range of specific combining ability (in hybrids for these traits) being -10.40 to 14.5 cm, -2.38 to 2.49 cm, -9.83 to 7.70g, -802 to 836 kg/ha and -320 to 343 kg/ha, respectively. The existing genetic variation for general and specific combining ability for agronomic and seed quality traits indicate that this genetic variation can be well used for production of high yielding and high seed quality hybrid cultivars.

This study was carried out to evaluate the effects of nitrogen fertilizer levels and plant density on forage yield and nitrogen use efficiency of sorghum bicolor in 2005 at Agricultural Research Center of Jahad-Keshavarzi, Ardabil. The treatments were arranged as split plots based on randomized complete block design of three replications. Treatments consisted of nitrogen fertilizer at three levels (0,75 and 150 kg/ha) and plant densities also at three levels of 6, 12 and 18 plant/m2. The results showed that sorghum can be harvested twice in environmental conditions of Ardabil. The highest forage yield resulted from an application of 150 kg/ha of nitrogen and planting of 18 plants m-2. The results of total forage yield at the two harvests indicated that sorghum forage yield was significantly affected by harvest (being the 1st or the 2nd), nitrogen levels, plant density, nitrogen level sorghum density, harvest x nitrogen levels, harvest x density. Densities of 12 and 18 plants m-2 resulted in similar yields, however, yielded more than the 6 plants m-2 treatment. Forage yield of the first harvest was more than the second harvest. Means of comparisons indicated that increasing the application of nitrogen fertilizer decreased nitrogen use efficiency. Nitrogen use efficiency decreased from 16.47 kg/kg for application of 150 kg/kg of nitrogen fertilizer to 14.97 kg/kg for application of 75 kg/ha of nitrogen fertilizer. Nitrogen use efficiency was affected by density, however no significant difference was observed between densities of 6 and 12plants/m2. Nitrogen use efficiency in the first harvest was observed to be more pronounced than that in the second harvest.

Deterioration of seed is one of the most important limiting or even hindering factors in its germination. An evaluation and understanding of the factors responsible for/and enhancing seed deterioration is of paramount importance. The main aim of this study was to determine the effects of seed deterioration on its germination and as well on the activities of antioxidant enzymes in canola cultivars. The experiments were carried out at seed and biotechnology laboratories of College of Agriculture, University of Tehran during 2004-2005. A completely randomized design of three replications was employed. The canola cultivars Licord (winter variety) and Option 500 (spring variety) were the ones studied. The seeds were aged through accelerate-aging and then germination characteristics measured. Such characteristics as germination percentage (%), germination index as well as germination speed we reassessed in all the experiments. Moreover, the levels of antioxidant enzymes, catalase and peroxidase, on these cultivars both under the aging and non-aging treatments and at three imbibition stages were measured. The results revealed that seed aging or deterioration reduced the percentage of germination, germination index and speed of germination in either one of the cultivars. For Licord cultivar, under the accelerate-aging test, all the aforementioned traits were higher than those of Option cultivar. Seed aging reduced the activity of enzymes. Extending seed hydration intervals increased catalase and peroxidase activities. However, the aged seeds had lower levels of enzymes as compared to non-aged ones. Licord, with a higher vigor benefited from a more enzyme activity than Option 500.

Iran is mainly situated in a dry climate part of the world. Due to the limiting and scarce water resources, crop production in the country is increasingly facing water shortages. A field experiment was conducted to investigate the impact of irrigation regimes on growth, chlorophyll fluorescence and grain yield of maize in 2006 at the Research Farm, College of Agriculture, Isfahan University of Technology, employing a 3-replicate split-plot RCBD. Four irrigation regimes (I1, I2, I3 & I4) constituted the main plots while four com hybrids (SC 704, SC700, SC500 and TC647) served as subplots. Such chlorophyll fluorescence parameters as F0,Fm and Fv/Fm in addition to growth and grain yield attributes were studied. While hybrids differed in their F0 at leaf10 stage, they differed with regard to Fm at teaseling stage. Plant height and LAI decreased with drought. Grain yield and yield components differed among hybrids and among irrigation regimes, with 14 yielding the lowest grain, as compared to other irrigation regimes. SC700 outperformed other hybrids in terms of grain yield. It seems that, at least according to the present study, a decreased photosynthetic area leaves a more pronounced impact on plant productivity, compared to a decreased efficiency of PSII under drought conditions. Since the Fv/Fm for different levels of irrigation applied, in this experiment, were not significantly different, using the latter ratio doesn't seem suitable for a determination of irrigation timing in the field.

Scarce water resources is a worldwide problem, still for Iran, a country predominated by an arid and semi-arid climate, water limitation is more severe than for many other areas of the world. A field experiment was conducted to investigate the impact of irrigation regimes on growth, grain yield and irrigation water use efficiency in maize (Zea maize L.) in 2006 at the Research Farm, College of Agriculture, Isfahan University of Technology, using a 3-replicate split-plot RCBD. Four irrigation regimes (I1, I2, I3,I4) constituted the main plots and four com hybrids (SC 704, SC700, SC500 and TC647) served as subplots. Despite harvest index, grain and biological yield and yield components differed among hybrids and irrigation regimes. Treatment 4 produced the lowest grain (7670 kg ha-1) biological yield (16650 kg ha-1) and irrigation water use efficiency for both grain (0.98 kgm3) and biological yield (1.42 kgm3), compared to other irrigation regimes. SC700 outperformed other hybrids in terms of grain (11220 kgha-1) and biological yield (23450 kgha-1). It seems that, at least with the present study, since seed/head was more correlated to grain yield than the rest of components, knowing physiological bases of seed set variation of maize under drought stresses helps to improve grain yield under latter conditions. Furthermore, for conditions where access to irrigation water is a limiting factor, supplying the water during the more vulnerable growth stages is crucial for a more production efficiency.

To study the effect of three soil fertilizing systems (chemical, organic, and integrated) on forage yield and quality of Globe Artichoke (Cynara scolymus) an experiment was conducted using a Randomized Complete Block Design (RCBD) of four replications at the Research Farm of College of Agriculture, University of Tehran, Karaj, Iran in 2006. The treatments included 5 levels of chemical fertilizers (40, 80, 120, 160& 200 kg/ha of N & of P), (48, 96, 144, 196 & 240 kg/1mofK), 4 levels of manure (10, 20, 30 & 40 ton//h), and 5 levels of mixture of different ratios of fertilizers and manure, as integrated systems along with a control (no fertilizer or manure application). The results showed that soil fertilization treatments significantly affected forage quantity and quality of artichoke. As for chemical fertilizers, total DM yield increased to 4.12 and 3.69 tons/ha through the treatments (in kg/ha) N200/P200/K240 and N160/P160/K192, respectively. For organic systems, the highest yields of 4.12 and 3.7 ton/ha were obtained by treatments of 40 and 30 tons of animal manure/ha, respectively. In the integrated system, the highest DM values of 4.49 and 4.1 tons/ha were obtained for the treatments of N80/P80/K96/manure 20,000 and NI20/P120KI44/manurel 0,000, respectively. The effects of three soil fertilization methods on forage quality traits were inconsistent. Chemical and integrated systems increased Crude Protein (CP), total dry matter, Dry Matter Digestibility (DMD) and Water-Soluble Carbohydrates (WSC) compared to the organic system of fertilizing. But organic system increased K and P contents as well as Acid Detergent Fiber (ADF) as compared to integrated and chemical treatment systems. It becomes evident that for chemical systems, moderate and high levels of chemical fertilizer and while for integrated systems, moderate levels of manure and chemical fertilizer exert significant effects on the quality and quantity of Globe Artichoke forage yield but not on DMD, K content, CP% and ADF. DMD and K content (in integrated systems) increased with an increase in manure and a decrease in chemical fertilizer levels. In contrast, CP% and ADF increased with a decrease in manure and an increase in chemical fertilizer levels. It is concluded that artichoke, as a new forage crop, has a suitable quantity and quality potential for livestock feeding when treated with proper of soil fertilization systems. But further and more thorough studies would be needed befor considering Artichoke as a new source of forage feed.

The prevalence of weeds in crops, with soybean being no exception, is a serious threat to the yield. Little research has been carried out to address the multiple weed species interference in soybean. A field experiment was conducted at the Research Farm of University of Tehran, Karaj, Iran during the growing season of 2006-2007 to determine the effects of different densities of single and multispecies populations of common cocklebur and red root pigweed on soybean yield as well as its yield components. Common cocklebur and red root pigweed were established at densities of 0, 2, 4, 8 and 0, 4, 8, 12 plants per one meter of row. Common cocklebur and red root pigweed seeds were sown concurrently with soybean and established at selected densities within 15 cm from either side of each soybean row respectively. The experimental design was randomized complete block with three replications. Results showed that biological and grain yield, pods per plant, weight of pods per plant as well as main stem height were significantly affected by densities of either common cocklebur or red root pigweed (p£0.05).Harvest index were not significant. Maximum soybean yield loss ranged from 39 to 86%, depending upon total density of weeds. Common presence of cocklebur and red root pigweed reduced soybean biomass, number, and weight pf pods per plant 79.9, 76, and 82% respectively. With increase in weed density, plant height increased except for the densities of 2 and 4 weed plants per row of crop, for common cocklebur and red root pigweed, respectively.

Although wild safflower (C.oxyacantha, 2n=24) has not been studied to a very large extent, yet it is believed that it can be used as an important source of biotic and abiotic stress resistance genes for improvement of cultivated safflower (C.tinctorius L., 2n=2x=24). In this study, the crossability between these two (cultivated and wild safflower) species was evaluated as based upon morphology and cytogenesis of F1 hybrid plants. Two accessions of c.oxyacantha (both spiny, yellow color of flower, brown seeded) were reciprocally crossed with two breeding lines of cultivated safflower (both spinessIess and white seeded, but yellow and red in color of flower). Morphological traits of hybrid plants were evaluated with heads of hybrid plants fixed in Carnoye's solution and chromosomes stained with Hematoxyline to detect for any probable chromosome abnormality. The results showed that when C.tinctorius (cultivated species) was crossed as female parent, more hybrid seed was produced as compared to the reciprocal cross process. Seed set percentage was 43 to 67% when cultivated species was used as female parent, but percentage of seed set was 0 to 37% in the case of reciprocal crosses. Morphology of hybrid plants was more closely similar to wild parent plants in which lower leaves were lacerate and upper ones all lanceolate. In all crosses between wild species of yellow flower color and cultivated line of red flower color, the F1 hybrid plants emerged with yellow flower color, indicating the complete dominance of yellow color over red. Also seed coat color in all the F1 seeds was white, implying that white color is dominant over brown seed color. An investigation of meiotic cells in F1 plants indicated that there existed a complete homology between the two genomes of the cultivated vs wild Carthamus species and while complete bivalent pairing being observed. In general, this study showed that two cultivated and wild species of safflower are crossable, thus the genes of desirable traits from wild species can be transferred to the cultivated one through classical breeding methods.

In order to develop molecular markers based on Expressed Sequence Tag (EST) linked to Fusarium Head Blight (FHB) resistance genes in wheat, the biological function of 8660 ESTs deposited in data bank were studied following which 260 ESTs with identified biological function were selected. In total, 62 primer combinations were designed based on conserved and non conserved sequences. Linkage and QTL analyses results, using phenotypic and genotypic data on F3 and F5 generations developed from the crosses 'Frontana' (moderately resistant)/ 'Falat' (susceptible), indicated that one designed molecular marker based on NPRI explained up to 9.6 % of AUDPC variance with a significant negative additive effect. This marker was located on 3AS.chromosome. The Expression of NPRI, using QRT-PCR method, indicated that the expression of the gene following 96 hours after inoculation in 'Wangshuibai' and 'Frontana', was on the increase. Therefore, NPRI and its developed molecular marker could be considered in future research programs to improve FHB resistance in wheat.

In order to determine the stoamatal and non-stoamatal factors limiting photosynthesis under drought stress, this experiment was conducted on seven wheat cultivars namely: Roshan, M-79-17, M-79-4 (drought tolerant), Azadi and Kavir (semi tolerant), Karajl and Marvdasht (drought susceptible) at the greenhouse of College of Agriculture and Natural Resources, University of Tehran. The experiment was designed as a factorial (factors comprised of two irrigation levels and seven wheat cultivars) of a Randomized Complete Block Design. Whereas relative water content of Marvdasht decreased severely under drought stress, no significant decrease was observed for M-79-4. On the other hand, Roshan exhibited the highest photosynthesis rate and the lowest photosynthesis reduction under drought stress conditions. In contrast, Marvdasht showed the lowest photosynthesis rate and the highest photosynthesis reduction under drought stress. A low photosynthesis rate in drought susceptible cultivars is due to a limitation, or low stomatal conductance, and as well due to non stomatal (low mesophyll conductance, chlorophyll and soluble protein content) factors. Thus it can be concluded that tolerance of genotypes to drought stress is closely associated with their higher stomatal conductance, leaf chlorophyll and soluble protein contents.