مجله علوم گیاهان زراعی ایران
سال چهل و سوم شماره 2 (تابستان 1391)

Barnyardgrass has always been considered as the most important weed of rice all over the world. Meanwhile, establishment of new species of this genus which is more adaptable to paddy ecosystem will increase the importance of this genus as a new threat to rice. In order to evaluate the competition of two species of barnyardgrass with rice, an experiment was conducted at Rice Research Institute of Iran (Rasht) in 2007. The experimental design was a randomized complete block with three replications arranged in a partial additive series. The treatments included two barnyardgrass species (E. crus-galli and E. oryzoides), and species density at four levels (0, 10, 20 and 40 plant.m-2), transplanted with Hashemi land races cultivar rice in local normal density (20 bunches.m-2) and each bunch included three seedlings. Destructive samples were taken two weeks after transplanting up to harvesting, that is, 5 times by 10 days interval in 0.25 m-2. Rice total dry matter accumulation (TDM), Leaf area index (LAI), crop growth rate (CGR), relative growth rate (RGR), yield and yield components were measured. Results showed that yield, yield components and growth indices were affected by both weed species significantly and no interaction between species occurred. Fitting the hyperbolic yield loss model to rice grain yield in barnyardgrass density showed that two weed species were not significantly different. Morphological similarity and ecological adaptability of new barnyardgrass species including resistance to flooding and also high similarity to crop plant that makes its hand weeding less efficient, implies E. oryzoides as a new threat for rice cultivation in northern paddy field of Iran. More investigation on biology of this species is suggested in order to present an applied integrated method for E. oryzoides management.

In order to investigate the effects of biological and chemical phosphorous fertilizers and various proportions of maize and grass pea intercropping on yield and yield components of both crops, two experiments were conducted simultaneously in Research Farm of Kerman University and commercial convention farm of Bardsir-Dashtkar in 2009-2010. The experimental design at two regions was randomized complete block design with four replications. The investigated factors included four phosphorous levels and five intercropping patterns. The compound analysis of data showed that the effect of location on most plant characteristics was significant. The effect of phosphorous levels and various intercropping patterns on thousand seed weight, seed numbers per row, grain yield, biological yield and harvest index of maize was significantly higher in %75 maize + %25 grass pea and %50 phosphorous biofertilizer + %50 chemical fertilizer treatment and the lowest of aforementioned traits obtained in the sole cropping of maize with no fertilizer treatment. The interaction of various intercropping patterns and phosphorous levels on pod number per plant, seed number per pod, grain yield, biological yield and harvest index of maize was significantly higher in %25 maize+ %75 grass pea and %50 phosphorous biofertilizer + %50 chemical fertilizer treatment. Results showed that LER in all intercropping systems was rather one and the highest LER was detected in %25 maize + % 75grass pea intercropping which indicates that intercropping had advantage over sole crop system. Therefore, this intercropping ratio with 50% biological phosphorous + 50% chemical phosphorous is suggested for Kerman situation.

In order to evaluate the effects of different planting dates and biological fertilizers on yield, yield components and essential oil content in Cumin (Cuminum cyminum) and Fenugreek (Trigonella foenum-graecum) intercropping, an experiment was conducted in a split-plot factorial arrangement in a randomized complete block design with three replications in research farm of Ferdowsi University of Mashhad in 2009-2010. The experimental treatments were planting date in three levels (5 November, 5 December and 5 March) assigned to main plots, planting pattern in three levels (sole crop of Cumin, sole crop of Fenugreek and intercropping) and fertilizer in three levels (control, Pseudomonas putida and nitroxin fertilizer including: Azotobacter chroococcum + Azospirillum lipoferum) were arranged as factorial layout in subplots. Result showed that there were significant differences between planting dates of cumin and fenugreek in terms of all studied criteria except in harvest index and 1000-seed weight. Seed, biological and essential oil yields of cumin and fenugreek were higher in fall planting dates compared to 5 March planting date. Percentage of infected cumin plants by diseases was decreased in November and December planting dates (7.72 and 7.67%, respectively) compared to March planting date (36.16%). Effects of planting patterns was significant in terms of seed and essential oil yield of cumin and fenugreek. Biological fertilizers had no significant effect on cumin oil yield and had significant effect on fenugreek essential oil yield compared to control treatment. Result showed that the LER for 5 March planting date was rather higher than fall planting dates which indicated the positive effects of cropping system in this planting date. Also, pseudomonas treatment had higher LER compared with nitroxin and control treatments. Generally, the higher seed and essential oil content of cumin and fenugreek were obtained in nitroxin and pseudomonas treatments, respectively, at November planting date.

Drought and salinity stress are adverse environmental factors that affect crop growth and yield. Abiotic stress cause some reaction in plants such as change in gene expression, cell metabolism, growth and yield. Moreover, stress condition resulted in increase of reactive oxygen species and disturbe macromolecules such as proteins, fatty acids, nucleic acid and pigments. In order to evaluate salinity effect on leaf proteome pattern and changes in antioxidant activity of two barley (Afazal, L.527) genotypes, an experiment was carried out using factorial experiment in a completely randomized design with three replications under controlled conditions and salinity (200 and 300 mM) stress. Salinity stress was imposed in seedling with 4-5 leaves stage for 24 hours. Salt stress decreased the catalase activity while increased the other antioxidant activity such as peroxidase, ascorbate peroxidase and glutathione reductase. Although the response of genotypes was different. Analysis of gels revealed that in tolerant genotype 97 protein spots (%78 up-regulated, %22 down-regulated) and in susceptible genotype 94 protein spots (%37 up-regulated, %63 down-regulated) showed significant changes in compare with control. Result of MS/MS led to the identification of some proteins involved in antioxidant activity, energy generating and other mechanisms.

The objective of this experiment was to determine the effects of different levels of nitrogen (N) and salinity on biochemical mechanisms of two wheat genotypes. A field experiment was carried out in a three replicate RCBD split factorial experiment in salinity station of College of Agriculture, Ferdowsi University of Mashhad, Iran in 2007-2008 and 2008-2009. Three levels of salt stress (1.3, 5, 10 dS/m) served as main plots and a combination of three levels of sulfate ammonium (50, 100, 150 kg N/ha) and 2 genotypes namely, Bam (resistance) and Toos (susceptible to salt stress) served as subplots. Results indicated that the effect of year on most characteristics was significant. Also under salinity stress, N application (100 and 150 kg N/ha) caused a significant effect on both genotypes with respect to biochemical and yield attributes [soluble proteins, SOD, CAT and APX activity]. Also the highest and the lowest MDA content was observed at 10 dS/m salinity level with 50 and 150 kg N/ha, respectively. The salt-tolerant and sensitive genotypes exhibited maximum value for physio-biochemical and yield attributes at 100 and 150 kg N/ha, respectively. These results suggest that application of N may improve most of the traits and is demonstrated to have physiological benefits and/or reduce the injurious effects of salt stress in wheat.

To study the effects of different fertilizing systems using green manure and zeoponix on grain yield and its components in sunflower, an experiment was conducted at the Research Farm of Collage of Agriculture, Tarbiat Modares University in 2010 and 2011. The Experimental treatments were arranged as split plot design on the base of a complete randomized block design with three replications. Two farming systems (with and without green manure) were assigned to the main plots and different fertilizing treatments consisted of zeoponics (control), zeoponics+25% chemical fertilizer, zeoponics+50% chemical fertilizer, and zeoponics+75% chemical fertilizer were assigned to the sub plots. The combined analysis of variance showed that using green manure in crop sequence increased the number of seeds per head. Interaction of green manure and zeoponix application affected biologic yield of sunflower. Green manure and 100% zeoponix and green manure and 25% zeoponix + 75% chemical fertilizer were the superior treatments. The highest amounts of 1000 seed weight, seed yield and oil yield were observed in 100% zeoponix and then 50% zeoponix + 50% chemical fertilizer treatments. These treatments were known as the best treatment to introduce for farmers to use. The highest protein percentage was observed in 25% zeoponix + 75% chemical fertilizer and 50% zeoponix + 50% chemical fertilizer. Regarding to oil quality, palmitic acid percentage was decreased by presence of green manure in crop sequence.

Studies of genetic diversity of plant populations are very important tools for plant breeders. In this study, 110 rice genotypes, including 39 Iranian local, 20 Iranian improved and 51 foreign improved varieties were studied for 14 agronomic traits in the the rectangular lattice design at the Rice Research Institute of Iran (Rasht). The analysis of variance showed that there were significant differences between cultivars for all the studied traits that indicates high genetic diversity among cultivars. Correlation analysis showed that grain yield was highly correlated with tillers per plant (rp =0.669 and rg =0.711), single panicle yield trait (rp =0.544) and number of filled grains per panicle (rp=0.454 rg=0.455), respectively. The results of factor analysis showed that seven main factors including panicle type, plant yield, plant height, plant shape, leaf shape, awn and seed shape, explain 77.68 percents of the total variance. Also the KMO coefficient was 0.64 that showed the relative preference of using of analysis factor. Cluster analysis using ward's minimum variance method, classified cultivars and characters in three and six groups, respectively. The accuracy of the cluster analysis was measured with the discriminant function and the respected amount was about 95 and 91 percent for the grouped varieties and characters. Results of factor analysis and cluster analysis confirmed each other.

Frost tolerance of winter wheat depends primarily on a strong vernalization requirement, delaying the transition to reproductive phase. The responses of four bread wheat cultivars (Triticum aestivum L.) to low-temperatures were examined in controlled environment and field conditions. Prolonged cold treatment accelerated the transition to reproductive development in winter wheats (cv. Norstar and cv. Shahryar) and facultative wheat (cv. Alvand), but not in a spring wheat (cv. Kavir). Exposure to low temperatures also enhanced frost tolerance of the winter and facultative wheats. Maximum frost tolerance was achieved around the point where further cold treatment caused no additional acceleration of flowering time; the vernalization saturation point.This greatest frost tolerance potential was observed in the winter wheat Norstar, which required the longest cold treatments to fulfill the vernalization response. The increased frost tolerance observed after exposure to low-temperatures (cold acclimation) was associated with reduced water but increased sugar content, and there was a strong association between frost tolerance and increased fructan content in the crowns. Fructan levels increased proportional to the length of cold treatment until the vernalization saturation point was reached. These data support the hypothesis that vernalization and cold acclimation pathways are interconnected in cereals and that the delay of floral development until spring is critical to allow acclimation to lowtemperatures during winter.

The aim of this study was to investigate the effects of winter crops residues on weed control, physiological indices, yield and yield components of potato. An experiment was carried out at the research farm of Colleg of Agricultural of Bu-Ali Sina University in 2009. The experiment was a randomized complete block design with three replications. Residues of rye, oilseed rape, triticale, barley, chemical weed control and control (no cover crop and no chemical control) were the experimental treatments. The results showed that winter cereals residues produced more biomass than winter oilseed rape residues. Cover crop treatments showed significant different in weed control of potato at 3 times (15, 45 and 75 days after germination) in compare to control treatment. Residues of oilseed rape and rye had the most inhibition affects on summer weeds. These treatments, decreased average biomass of weeds by 61 and 57 percent, respectively, in compare to control. Oilseed rape and rye residues in compare to control, reduced weeds density in potato by 36 and 35 percent, respectively. Residues of oilseed rape and rye improved physiological indices of potato. A significant correlations of weeds plant population, weeds dry matter, physiological indices and average tuber weight of potato with potato yield was detected. The treatments of oilseed rape and rye in compare to control, increased tuber yield of potato by 54 and 50 percent, respectively. These treatments, increased the average tuber weight by 74 and 38 percent, respectively, in compare to control,.

To evaluate the quantitative and qualitative of forage in intercropping of sorghum and chickling pea under limited irrigation systems, an experiment was conducted in Research Farm, College of Agriculture, University of Tehran, during 2009 and 2010. The treatments were arranged as split plots consisted of three levels of irrigation regimes including control (irrigation after 70mm evaporation from evaporation pan class A) (IR70), moderate limited irrigation (irrigation after 100mm evaporation from evaporation pan class A) (IR100) and sever limited irrigation (irrigation after 130mm evaporation from evaporation pan class A) (IR130) assigned to the main plots and eight sole and intercrop combinations of sorghum and cowpea including sole cropping of sorghum (weed free), sole cropping of sorghum (weed infested), sole cropping of cowpea (weed free), sole cropping of cowpea (weed infested), sorghum + 40% cowpea, 6. sorghum + 60% cowpea, sorghum + 80% cowpea and sorghum + 100% cowpea were assigned to the subplots. A complete randomized block design with three replications was used to analyze the data. As the water stress increased, the total forage yield followed a decreasing trend. The total forage yield decreased by 28% in sever limited irrigation (IR130) compared to control (IR70). The additive intercropping of sorghum and cowpea in all combinations over produced the sole cropping of each crop both in weed infested and weed free treatments. The highest total forage yield was produced in sorghum+60% cowpea treatment. The total forage yield in 2009 was higher than 2010. As the proportion of cowpea in additive intercropping with sorghum increased at normal (IR70) and moderate (IR100) limited irrigation systems, the total forage yield followed a decreasing trend while in severe limited (IR130) irrigation regime total forage yield increased. The highest crude protein content of 9.9 percent was achieved in sorghum+40% cowpea and sorghum+60% cowpea treatments. The highest soluble carbohydrates contents of 16.8% was achieved in moderate limited irrigation regime (IR100).

In order to evaluate the effects of nitrogen levels and its split application on growth indices and their relationship with grain yield of rice (cv. Khazar), a field experiment was conducted at Rice Research Institute of Iran with 11 treatments arranged in a randomized complete block design with 3 replications in 2008. Nitrogen fertilizer levels (10, 20 and 30 kg.ha-1) were applied according to three chlorophyll meter (SPAD-502 reading thresholds) (36, 38 and 40) of fully developed leaf of rice plant. Results showed that in S38N30 (SPAD38+30 kgN) and S40N30 (SPAD40+30 kgN) treatments which were received maximum rate of nitrogen fertilizer (103 kgN.ha-1), maximum LAI (3.13 and 3.28) and CGR (29.86 and 29.34 g.m-2) were observed and in S40N30 treatment maximum LAD (1392.86 cm2.day-1) was observed. Analysis of regression showed that there was a significant linear relationship between grain yield and CGR (r2= 0.87**), LAI (r2= 0.88**) and LAD (r2= 0.76**). Maximum grain yield and nitrogen agronomic efficiency (5955 kg.ha-1 and 23.5 kg.kg-1, respectively) were also observed in S40N30 treatment. It seems that the main reason of increasing grain yield in this treatment was improvement of growth indices (CGR, LAI and LAD, respectively) and effective consumption of nitrogen fertilizer. Considering higher grain yield and nitrogen use efficiency in this treatment, it seems that split application of nitrogen in proper rate according to plant demand, may economize nitrogen fertilizer and prevent of its losses in rice production.

In order to investigate the absorption and translocation of glyphosate and 2,4-D during various stages of growth in swallow-worts weed populations, this study was carried out in 2010 at the Iranian Agricultural, Medical and Industerial Research Institute of Atomic Energy Organization. Treatments used in this study included three different stages of growth, four weed ecotypes of swallow-worts, and two types of herbicides labelled with carbon 14 (glyphosate and 2,4-D), respectively. Extraction and counting of labelled herbicide showed that herbicide absorption and translocation in different growth stages of different ecotypes of swallow-worts considering the absorption and transfer to different parts of the plant were significantly different. Labeled glyphosate herbicide detected in swallow-worts rhizome showed that the development of recycling and transport to the site of inoculation and shoot to root at the highest levels were different. The least amount of herbicide uptake and transport of herbicides to the leaves above the inoculation site and the plant was in Ahwaz ecotype and other ecotypes and growth stages were not significantly different from each other. But in the case of herbicide transport to the inoculation site and transporte to the roots, Ahvaz ecotype had the highest transmission and the rest showed no significant differences. Different ecotypes also showed significant differences in absorption and transfer steps. Detection of labelled glyphosate herbicide in swallow-worts showed that there was no significant difference in the percentage of transport to a higher place of the inoculation site and transport to the root between ecotypes. However, the transfer of herbicide to the lower site of inoculation and the target leaves were significantly different. This study also showed that the uptake and transport of herbicide 2,4-D in all stages and in different ecotypes with different levels were significantly different. By detection of this herbicide in the plant, it was shown that, except to the amount of absorption by the target leave, the remaining steps of capturing, transporting and recycling of herbicides were significantly different.

In order to locate the QTLs involved in the inheritance of agronomical, physiological and metabolitical indicators of drought tolerance in barley, an experiment was carried out using a wheat-barley disomic addition lines. This research was conducted in 2003-2004 at the Dry Land Agricultural Research Institute, Sararood, Kermanshah, Iran. The results of analysis of variance revealed highly significant differences for most of the investigated traits. Mean comparison exhibited that most of the genes controlling drought tolerance criteria are located on chromosomes 4H and 5H. The overall consideration of the indices using stress tolerance index (STI) and physiological multiple selection index (MSI) indicated that most of the QTLs responsible for the genetics of drought tolerance predictors are located on chromosomes 4H and 5H. A three dimensions-plot and cluster analysis confirmed the same conclusion. In correlation analysis, chlorophyll a and b and also proline were detected as indicator of drought tolerance, but excised leaf water retention (ELWR), relative water content (RWC), relative water deficit (RWD), relative water loss (RWL), chlorophyll fluorescence (CHF), cell membrane stability (CMS) and leaf chlorophyll content (LCC) are proved to be physiological indices of drought tolerance.

Breeding based on selection indices is an effective method for improving complex traits such as yield. To assess the efficiency of different selection methods, 50 genotypes of tall fescue (Festuca arundinace) were evaluated under two moisture conditions including full irrigation (normal environment) and deficit irrigation (stress environment). The experiment was conducted according to a randomized complete block design with three replications during 2009 and 2010. Selection indices were calculated based on Smith-Hazel and Pesek-Baker methods by five traits including number of stem per plant, leaf/stem ratio, plant height, percent of dry matter and crown diameter under both conditions in two forms (with and without dry matter yield). Also response to selection and relative selection efficiency were estimated for studied traits and dry matter yield. Results showed that genotypes with the highest number of stem, leaf/stem ratio, plant height, crown diameter and the lowest percent of dry matter had the highest yield potential. In Smith-Hazel index under both moisture conditions, dry matter yield and number of stem per plant had the highest gain, while in Pesek-Baker index, dry matter yield had a negative gain. Result indicated that Smith-Hazel index (with yield) had the most selection efficiency and can be used in tall fescue breeding programs.

The first step in breeding programs is detecting the genetic diversity in breeding materials. Molecular markers help to reduce costs and time in breeding programs. Genetic variation in 49 genotypes of tobacco were studied using 12 ISSR markers, 3 Retrotransposon markers and the combination of ISSR and Retrotransposons. One hundred forty seven polymorphic bands were produced using 16 primers. Tos-2 primer with 16 followed by UBC811 and TOS-1 with 14 bands had the maximum and UBC825 and TOS- 3 with 4 band had the minimum polymorphic bands. PIC value varied between 0.27 to 0.46 and MI between 1.15 to 5.87. Principal Coordinates Analysis showed that the aforementioned values could explain total variation of 16.75 percent. In this study, cluster analysis using UPGMA, placed 49 genotypes in five cluster groups. Groups include 9, 4, 1, 13 and 22 genotypes, respectively. Discriminate Function via Fisher's linear (79.6 percent) confirmed the validity of clustering analysis result.