Iran Agricultural Research
Volume:28 Issue: 1, Winter and Spring 2010

A greenhouse study was conducted to investigate the effects of nitrogen(N) on wild barley (Hordeum spontaneum Koch) interference with winter wheat(Triticum aestivum var. Pishtaz) by an additive series experiment. The experiment wasconducted in a split plot design with 3 replications. Wheat plant height losses were onaverage 30, 10, and 10% in a wild barley density of 16 plants per pot with an N supply of40, 80, and 160 mg per kg soil, respectively. At all N application rates, wheat tillersdecreased in the presence of wild barley densities of 4, 8, and 16 plants per pot.Increased N stimulated wheat tiller growth per plant but this effect was reduced by wildbarley interference. The highest leaf area was observed at 80 mg N per kg soil for bothspecies in monocultures. Significant differences were observed among wheat dry weightvalues in all wild barley densities and at each level of N application rate. Shoot Nconcentration of wild barley was greater than that of wheat. Wild barley competitionalways reduced shoot N concentration of wheat and this was increased with increasingwild barley density. The results of this study suggested that wild barley is moreresponsive to soil N levels than wheat.

Chinaberry (Melia azedarach L.) is a beautiful tree indigenous to the Himalayas that grows as a native plant in Iran. Symptoms similar to bacterial gall have been observed on the crown, shoot and twig of chinaberry, a recent landscape tree since 2003-2004 in Shiraz, Fars province, south of Iran. A gram negative bacterium was isolated from the galls. The isolates did not produce fluorescent pigment on King's B medium, were negative in oxidase, levan production, potato soft rot, casein, gelatin hydrolysis, nitrate reduction, growth at 5oC, uease production and indol production, but were positive in arginine dihydrolase, catalase, growth at 35oC, and also produced hypersensitive reaction on tobacco. Wound inoculated bacterial suspension into chinaberry seedlings produced galls from which the bacterium was reisolated. Systemic movement of the isolates into the vascular system of chinaberry was shown by the formation of gall above the inoculation site on the stem. On the basis of biochemical, physiological and pathogenicity characteristics, the isolated bacteria were identified as Pseudomonas meliae. Electrophoretic pattern of cell proteins showed that chinaberry isolates were different from P. syringae, P. viridiflava, P. fluorescens, P. savastanoi. The current article is the first report of bacterial gall disease of chinaberry in Iran.

Trichoderma species are among important antagonists of plant pathogenic fungi. The main purpose of this study was to evaluate the biocontrol potential of native Trichoderma spp. isolates from sugar beet fields against Phytophthora drechsleri and P. cryptogea, the causal agents of Phytophthora root rot of sugar beet. During 2007–08, 85 isolates of Trichoderma spp. from sugar beet fields in eight parts of Fars province, Iran were isolated. Based on morphological and physiological characteristics, eight species could be distinguished: T. asperellum, T. atroviride, T. brevicompactum, T. harzianum, T. longibrachiatum, T. spirale, T. tomentosum and T. virens. Their antagonistic activities including competition, colonization and antibiosis against Phytophthora isolates both in vitro and in planta were investigated. Different species and even different isolates of one species differed in their antagonistic capacities. High competitive abilities were shown by T. asperellum, T. atroviride, T. harzianum and T. virens in pre colonized plates, and by the former three species in dual cultures. T. harzianum and T. atroviride efficiently colonized both species of Phytophthora. T. asperellum Ksh2, T. virens DB6r, T. virens DB2 and T. virens DB3 and T. harzianum MS3 gave the highest growth inhibition. In in planta experiments, T. harzianum MS3 and FG4 and T. virens DB6r were the most efficient in suppressing root rot of sugar beet seedlings. Our results suggest that T. harzianumMS3 is the best native candidate for the biocontrol of this disease.

Water deficit is an important factor limiting crop growth all over the world. In order to evaluate genetic variation, heritability and the interrelationship between agronomic traits, twenty chickpea genotypes were cultivated in two separated randomized complete block experiments with three replications under normal irrigated and rainfed conditions. The experiments were carried out at the Agricultural Research Station of Razi University, Kermanshah, Iran, in the 2004-2005 growing season. Under normal conditions, plants were irrigated at stem elongation, pod appearance and pod filling stages. In rainfed conditions, no irrigation treatment was applied. The results revealed that the genotypes S95274 under irrigated and X95TH69 in rainfed conditions had the highest number of pods per plants (NPP), number of seeds per plant (NSP) and grain yield. The genotypes X96TH54 and X95TH69 produced relatively high grain yield compared to other genotypes in both conditions. The highest genotypic and phenotypic coefficients of variation in irrigated (32.61% and 34.67%, respectively) and in rainfedconditions (47.88% and 49.39%, respectively) and also the highest estimation of heritability in both conditions (88% and 93%, respectively) belonged to grain yield. In rainfed growing conditions, the correlations between grain yield and its components were significantly positive while in irrigated conditions grain yield showed significant correlation with NPP (r=0.50) and NSP (r=0.49). According to the results of path analysis, the highest direct (0.99 and 0.73 in irrigated and rainfed conditions, respectively) and indirect effects (0.89 in irrigated and 0.71 in rainfed experiments) ongrain yield belonged to NSP and NPP respectively. Based on cluster analysis method, genotypes were classified into three and four groups in irrigated and rainfed conditions, respectively. It can be concluded that the NPP and NSP traits could be used as selection criteria for grain yield improvement in both conditions in chickpea breeding programs.

Effects of water stress and Fusarium oxysporum f. sp. lycoperseci (Fol) on the growth of tomatoes were studied in a greenhouse experiment. Treatments consisted of five levels of water stress (1, 3, 5, 7 and 9 day irrigation intervals). Infested soil consisting of 400 chlamydospores g1 of Fol and non infested soil were used. Experiments arranged in a completely randomized design with 8 replications (4 infested and 4 non infested soil) under greenhouse conditions (18-35 0C). Six week old tomato seedlings, cultivar Porimo, were exposed to water stress after transferring to infested and non infested soils. During the experiment, leaf area, final plant height, shoot dry weight and shoot nitrogen content were measured. Disease symptoms appeared earlier in treatments with high water stress than the other t reatments. Results showed that leaf area, final plant height, shoot dry weight and shoot nitrogen content were reduced both with increasing irrigation intervals and in infested soils. Root colonization by Fol increased with increasing irrigation intervals, but differences were not significant.

Cadmium (Cd) concentration in soil solution and its bioavailability is controlled by sorption-desorption reactions. The objective of this research was to compare Cd adsorption behavior in six calcareous and four acid soils. Soil samples were equilibrated with 0.01 M Ca(NO3)2 containing 25 to 3200 mg Cd L−1. Results showed that the tendency for adsorption was high at low Cd concentrations (0-400 mg L-1), but decreased as the Cd increased (400-3200 mg L-1). Among five equations evaluated, Freundlich, Langmuir, and Gunary equations best described Cd adsorption in both calcareous and acid soils as indicated by high values for coefficient of determination (R2) and low values for standard error of estimate (SE). Stepwise regression equations between constants of the best-fitted models and soil properties revealed that cation exchange capacity (CEC) and clay content were the most important soil properties affecting Cd adsorption behavior in calcareous soils, whereas in acid soils Cd adsorption was mainly affected by soil pH. Constants of the best fitted models showed good correlations with pH, clay, and calcium carbonate equivalent (CCE) in combined calcareous and acid soils. Our tentative conclusion is that higher pH in calcareous soils resulted in greater negative exchange sites available for Cd sorption, therefore Cd adsorption in these soils is greater compared to that of acid soils.

The objective of the present study was to determine if modificationswould occur due to epinephrine perfusion and simulating stressful situations (2 μg/ kg/min, an animal)and transportation,causing change of the values of extractable proteinconcentrations, SDS PAGE profiles and the calpain calpastatin complex in silver rabbitlongissimus muscles resulting in consequent changes in meat tenderness. Approximately60 standard rabbits, 70 days of age, were weighed and randomly assigned to epinephrineand transport treatments along with their controls at 3 times: immediately after slaughter(time 0), 24 hr and 7 days post mortem. The results showed there was a significant(p<0.05) lower value of extractable protein concentrations for treatments in controlsamples than the stress treated ones after 7 days of storage. Also, the comparison of SDSPAGE profiles at times 0 and seven days exhibited several differences due to the originof the samples, especially around 30 KD, the intensity of the band is similar in allsamples at time 0 while it decreases after seven days of storage in all samples except forthose from the epinephrine treatment. On the contrary, after seven days of storage, theresults indicated that dot blots against calpain were lower in the epinephrine sampleswhile they were the highest in control treatments. Transport samples had an intermediateposition. The results showed that epinephrine infusion and transport certainly modifiedmuscular protein degradation. Therefore, variability in the rate of meat tenderization mayarise as a result of stress induced activity or suppression of key proteolytic enzymesinvolved in myofibrillar protein turnover. Those alterations are due to modifications ofthe calpain calpastatin complex. The decrease in protein degradation was due to adecrease in calpain concentration.

Phytate phosphorus of plant ingredients is not substantially available to poultry because of the lack of endogenous phytase enzymes in their gastrointestinal tract. There are substantial differences among broilers, turkeys, and ducks in terms of plant P utilization. We studied whether the availability of P is different for two Phytase enzymes in turkeys. Finase and a New Phytase product developed recently were tested in 3 to 5 week old turkeys. The efficacy of Finase and the New Phytase were determined on the basis of P balance and tibia data. A low P maize soybean meal based diet was supplemented at 0, 250 and 500 FTU/kglevels of Finase and 0, 250, 500 and 750 FTU/kg of the New Phytase. Excretions were collected in a balance trial and tibia parameters were obtained after the turkeys had received their respective diets for 17 days. Utilization of P from the basal diet was 35.5% which significantly improved by Finase to a maximum of 47.3% and by the New Phytase to a maximum of 48.7% at the highest level of supplementation. The utilization of Ca did not improve. Tibia ash concentration improved by Finase and the New Phytase supplementation. It is concluded that the Finase and the New Phytase efficiently improve the utilization of P in turkeys and may help protect the environment by causing a reduction in excretion P.

Although, grapevines do not have a high chilling requirement, its fulfillment is critical for normal development of the vines. In tropical and subtropical regions such as Farrashband, in the south of Iran, there is no adequate winter chilling to release bud dormancy in grapevines. So it is necessary to consider the effect of chemical dormancy–breaking agents on bud dormancy. In the present research an aqueous solution of dormex (3.5 and 7%, v/v), volk oil (3.5 and 7%, v/v) and potassium nitrate (1.5 and 3%, w/v) were sprayed at two separate dates (26th Jan. and 11th Feb. 2007) on pruned canes of vines in Farrashband region, Fars province, Iran. Results indicated that the application of dormancy-breaking chemicals in the first spray was more effective than that of the second date with respect to advancing budbreak as well as flowering. Dormex (3.5%) and KNO3 (1.5%) were found to be more effective than other treatments. The highest cluster weight was obtained in dormex (3.5%) and KNO3 (3%). Dormancybreakingchemicals and time of application had little effect on TSS, total acid and the vitamin C of ripened fruits. In general, dormancy-breaking agents and time of application positively affected advancing budbreak as well as flowering as a result of increased yield. In warm climates where the amount of chilling is not sufficient, the application of dormancy-breaking chemicals (Dormex, KNO3, Volk oil) at the proper time may overcome bud dormancy.

Matricaria chamomilla is a medicinal plant that is widely cultivated in salt affected soils. This investigation was undertaken to study the effect of NaCl concentration on germination, and the physiological, biochemical and growth characteristics of chamomile. Seed germination and growth were studied at five NaCl concentration levels (0, 40, 80, 120 and 190 mM NaCl concentration). Increasing the level caused significant reduction in seed germination. Salt concentration up to 40 mM led to higher growth, but more than 40mM of NaCl caused significant growth limitation. Chloride and sodium ions increased significantly in various parts of the plant with salinity. Specifically, chloride ions were predominantly concentrated in the shoots whereas sodium ions were concentrated mostly in the roots. With increasing salinity rate, K and Ca concentrations significantly decreased in the shoot and root of M. chamomilla as compared to the control. There was a consistent decrease in K+/Na+ and Ca2+/Na+ ratios in the shoots and roots of M. chamomilla. Plants maintained considerably higher K+/Na+ and Ca2+/Na+ ratios in the shoots than the roots, and the former ratio was significantly higher than 1 in a 40mM salinity level. No change in leaf proline concentration was observed up to 80 mM, but a sharp rise at higher salt levels occurred. Overall, based on the results, M. Chamomilla is a tolerant to moderately salt tolerant crop during its growth, and its response to salinity is associated with the maintenance of high K+/Na+ and Ca2+/Na+ ratios in shoots, the accumulation of Na+ in roots, and proline accumulation in shoots.