Iranian Journal of Crop Sciences
Year:2015 | Volume:17 | Issue:3|Papers Count:6

To study the effect of mixture of herbicides on weeds control in rainfed bread wheat in Ardabil (Germi, Iran) a filed experiment was carried out using randomized complete block design with four replications in 2009-2011 cropping seasons. Experimental treatments included; hand weeding, 2, 4-D (U 46D), Clodinafop - propargyl (Topic), Fenoxaprop pethyl+Mefenpyridiethyl (Puma Super), Tribenuron methyl (Granstar), Difenzokvat (Avenge), 2, 4-D+Topic, Topic+Granstar, Puma Super+2, 4-D, Puma Super+Granstar, Avenge+2, 4-D, Avenge+Granstar, control (Weedy) and fallow with roundup (glyphosate). Herbicides were used at recommended doses. Analysis of variance showed that different herbicides had significant effect on reduction (%) of Gladiolus, wild oats and other weeds density. Maximum reduction (%) of Gladiolus (100%, 88.12% and 61.32 %), wild oats (93.24%, 95.13 % and 94.72 %) and other weeds density (83.36%, 98% and 75.90%) was observed in two times hand weeding, fallow+Glyphosute and Topic+Granstar, respectively, also maximum reduction (%) of Gladiolus and other weeds biomass was observed in Topic+2, 4 -D. of Year × herbicide interaction effect was significant on grain yiled. The higher grain yield was obtained in Topic (2595 kg.ha-1), hand weeding (2571 kg.ha-1) and Pumasuper+Granstar (2269 kg.ha-1) in 2010. In conclusion, results of this experiment showed that Topic or Topic+2, 4-D can be used for weed control in rainfed weed in Germi region in Ardabil province of Iran. Aplication of Pumasuper+Granstar is also an option.

To evaluate drought stress tolerance and identifying of tolerant fennel varities/ecotypes, three synthetic fennel varieties and their seven parents in two separated experiment; normal irrigation and post flowering drought stress were carried out in a complete block design with three replications in 2013 in Aburihan campus, university of Tehran, Iran. Analysis of variance showed that there was a significant difference among varities/ecotypes for all the traits in two experiments, which implies genetic variation among the fennel germplasm studied. Mean comparison showed that the highest seed yield in normal irrigation belonged to medium maturity synthetic variety and Meshkinshahr ecotype with 2357 and 2208 kg.ha-1, respectively. In drought stress condition Meshkinshahr ecotype and medium maturity synthetic variety produced 1091 and 1081.5 kg.ha-1, respectively. Considering drought tolerance indices, the highest mean productivity (MP), geometric mean productivity (GMP), yiled index (YI), stress tolerance index (STI) belonged to medium maturity synthetic variety, Meshkinshahr and Moghan ecotypes. Correlation coefficients between drought tolerance indices and seed yield showed that in both normal and drought stress conditions MP, GMP, YI and STI indices had positive and significant relationship with seed yield, and this implies that selection of drought tolerant varieties are possible. In conclusion, development of synthetic varieties of fennel is recommendable and developed varieties may produce better yield in water deficit prone environments.

To evaluate the effect of transplanting time on dry matter remobilization and grain yield of rice cultivars, a split plot arrangement in randomized complete block design was carried out with three replications in 2013 and 2014 at the College of Agriculture, University of Guilan, Rasht, Iran. The experiment consisted of six rice cultivars (Hashemi, Sangejo, Alikazemi, Dorfak, Khazar and Gouhar) and three transplanting times (05 May, 20 May and 05 June). Results showed that dry matter remobilization significantly increased from shoot to grains with delay in transplanting time. The highest dry matter remobilization was measured in Gouhar cultivar with 139.1 g.m-2 and the lowest in Hashemi, Sangejo and Alikazemi cultivars. Grain yield was positively associated with accumulated temperature and radiation. Highest accumulated temperature (1422.3 and 345.8oC in whole growing and grain filling periods, respectively) were recorded in the first transplanting time. Results also showed that the Photothermal Quotient index as a ratio of radiation and temperature can be used in explantation of observed variation in grain yield of rice cultivars. Suitable transplanting time can be chosen using accumulated PTQ as different plant growth stages experienced favorable conditions of temperature and radiation (137.4 Mj.m-2. oC for 3916.8 kg.ha-1 grain yield). In this study, transplanting on 05 May provided the favorable conditions of temperature and radiation during the vegetative and reproductive stages of rice cultivars and had positive impact on grain yield and its components.

Potassium fertilizers affect cadmium uptake and accumulation in plants under cadmium-contaminated soils.To determine the role of potassium in alleviating the adverse effect of cadmium in two durum wheat cultivars (Behrang and Yavaros), an experiment was carried out as factorial in randomized complete block design with three replications in Shahid Chamran university, Ahvaz, Iran in 2012. Experimental treatments included: control, 20 mg Cd kg-1 soil (CdCl2), 20 mg Cd kg-1 soil+two levels of 300 and 450 mg K kg-1 soil as potassium sulphate, and two levels of 30 and 45 mg K kg-1 soil as nano chelate potassium 27%. Cadmium on its own reduced grain yield, biological yield, chlorophyll index, relative water content, stomatal conductance, total chlorophyll content and grain K content in both cultivars (72, 50, 22, 23, 56, 30 and 53%, respectively), but grain Cd content was increased by 13 fold. Potassium application in combination with cadmium, especially in two levels of 30 and 300 mg K as nano chelate potassium and potassium sulphate, respectively, led to mitigating the negative effects caused by cadmium stress on agronomic and physiological traits. Grain cadmium content decreased in these treatemnets when compared with cadmium treatment. In conclusion, these findings showed that potassium plays an important role to improve durum wheat crop growth and reduce grain Cd content.

To study the effect of mychorizha, glysin betaein and sugar beet extract on some physiological and biochemical parameters of castor bean as a second crop under drought stress conditions, a split plot arrangement in randomized complete block design with three replications was carried out in the Agricultural Research Station of Oshnaviya, West Azarbijan, Iran, in 2012 and 2013. Drought stress applied at four levels (irrigation after soil moisture reached to 80%, 70%, 60% and 50% of field capacity) were as assigned to the main plots and foliar application with glycine betaine (50 mM), sugar beet extract (100%) and water (control) and the use of super absorbent gel A200 (225 kg.ha-1) and inoculation with mycorrhiza (Glomus mossea) were randomized in sub-plots. Foliar application of glycine betaine, sugar beet extract and water were carried out at leaf 10 stage of the plant, and mycorrhiza and super absorbent gel were applied at planting. Mean comparison showed that increasing stress intensity from 80% to 50% of field capacity decreased seed yield by 49%. The highest malondialdehyde content (177.2 nmol.gFW) was achieved in severe water deficit stress with spraying water (control). The highest seed yield (2730 kg.ha-1) and the highest activity of APX (117.9 A290.mg protein), CAT (87.1 A240.mg protein) and SOD (46.9 unit.mg protein) enzymes were achieved from foliar application of sugar beet extract. Therefore, at all levels of irrigation, glycine betain and sugar beet extract treatments through induction of tolerance mechanisims increased the activities of antioxidant enzymes and thus increased seed yield compared to control due to decreasing adverse effect of water deficit stress. Therefore, foliar spraying with sugar beet extract can be suggested to alleviate water deficit stress effect in castor bean.

Iron and zinc deficiencies in the diet of people in many countries have caused some health problemsSince the processes of micronutrients uptake, translocation and utilization as well as their accumulation in the grain are under genetic control, therefore, research for identification of genotypes with higher ability in uptaking micronutrients from the soil and accumulating high content of micronutrients in their edible parts is developing.The aim of this experiment was evaluation of genetic variation of 142 bread wheat genotypes for grain iron and zinc content and their relationships with grain yield and yield components under rainfed conditions. The experiment was conducted in an unreplicated statistical design at the experimental field station of Dryland Agriculture Research Institute, Kermanshah, Iran, in 2011-2012 cropping season. Bread wheat genotypes were compared with “cv. Rijaw” and “cv. Azar2” as control. Results indicated that the range of grain iron and zinc content was from 70 to 109 and 31 to 61 mg.kg-1, respectively. Concentration of grain zinc content in genotype“cv. Azar2” was significantly higher than “cv. Rijaw”. Grain iron content in none of the bread wheat genotypes was significantly greater than “cv. Rijaw” and “cv. Azar2”. Correlation between grain iron and zinc content was not significant.