Maryam Mansori; Gholam Abbas Akbari; Seyad Mohammad Mahdi Mortazavian
Abstract
To evaluate the effect of foliar application of nano-particles of titanium dioxide on yield and yield components of ecotypes of cumin under drought stress conditions, a split-split plot experiment was carried out based on a randomized complete block design with three replications, during 2014-2015 at ...
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To evaluate the effect of foliar application of nano-particles of titanium dioxide on yield and yield components of ecotypes of cumin under drought stress conditions, a split-split plot experiment was carried out based on a randomized complete block design with three replications, during 2014-2015 at the research farm of Aburaihan Campus, University of Tehran at Pakdasht. Treatments were consisted of water stress at three levels (full irrigation throughout growing season, water stress at vegetative and reproductive stages), spraying of nano-particles of titanium dioxide at three levels (no spray, spraying with concentration of 0.015 and 0.03 percentages) and also ecotypes of cumin from nine regions. Based on the obtained results the highest grain yield was belonged to Ardakan-Yazd in normal irrigation and spraying of nano-particles at concentration of 0.03 percent with an average of 194.05 grams per square meter, compared to non-sprayed treatment in which 17 percent lower grain yield was obtained. The highest grain yield also was observed at stress conditions in reproductive phase for ecotype of Maneh of North Khorasan at spraying of 0.015 percent of nano-particles with an average of 45.89 grams per square meter, when compared to the control (no spray) in which 16 percent lower grain yield was obtained. Ecotypes also showed significant differences at level of one percentage in terms of responses to drought stress. Based on the obtained results from spraying of nano-particles at a concentration of 0.03 percent, the negative effects of drought stress were reduced and this treatment prevented from huge yield loss under stress.
mojtaba khazaie; mohammad hassan hadizadeh; ehsan zaidali
Abstract
In order to determine the critical period of weed control (CPWC) in Corn (Zea mays L.), an experiment was carried out in a randomized complete blocks design with 14 treatments and three replications during 2013 growing season in the Nahavand climatic conditions. Two series of the treatments including ...
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In order to determine the critical period of weed control (CPWC) in Corn (Zea mays L.), an experiment was carried out in a randomized complete blocks design with 14 treatments and three replications during 2013 growing season in the Nahavand climatic conditions. Two series of the treatments including weed-free and weed-infested were applied in the regular time distances of 10, 20, 30, 40, 50 and 60 days after Corn emergence. Two check treatments including full and no control of weed during the whole season were also included. The nonlinear models kind of Logistic and Gompertz were applied to determine the start and end of critical period of weed control respectively. Major weed species were field bindweed (Convolvulus arvensis L.), red root pigweed(Amaranthus retroflexus L.), pigweed(Amaranthus blitoides L.) and lambsquarters(Chenopodium album L.) with greater biomass and size. The results showed that periods of weed- free and weed- infested differently affected the dry weight and number of weeds in all treatments. The critical periods of weed control in Corn by accepting a 5% acceptable yield loss, it is necessary to control weeds in a period between 14-47 days after planting or 117- 566 growth degree day(4-12 leaf stage) and by accepting a 10% acceptable yield loss it is necessary to control weeds in a period between 23-36 days after planting or 220- 419 growth degree day(6-10 leaf stage).