STUDY ON THE POTENTIAL OF RAPESEED CANOPY IN COMPENSATING PLANT DENSITY LOSS IN GROWING SEASON YIELD AND SEED YIELD COMPONENTS
Mohammad Javad Jazinizadeh1 and Saeed Sadeghzadeh Hemayati2
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The potential of rapeseed canopy in compensating the loss of plant density during growing season yield and seed yield components was investigated in Natural Resources Nursery of Bam, Iran in 2010-2011 as a factorial study based on a Randomized Complete Block Design with three replications in which the first factor was devoted to the time of plants removal including seedling emergence, stemming and flowering and the second factor was devoted to the intensity of plants removal at three levels of 25, 50 and 75%. There was a control in each replication. The evaluated traits included seed yield, and seed yield components (the number of pods per area, the number of seeds per pod, single-seed weight). It was found that rapeseed was more sensitive to the intensity of plants removal than to the growth stage at which the plants were removed. The loss of plant number per unit area resulted in higher seed yield per plant. Although as plants removal was delayed, the plants had more opportunity to compensate the removed plants by increasing seed yield per plant, the increase in seed yield per plant (20.7%) with the removal of 15% of plants was equal to the decrease in seed yield per unit area (20.8%). Therefore, maximum seed yield can be obtained in Bam, Iran by reducing the density to 57 plants m-2. The evaluation of the trend of the response of different seed yield components to the variation of plant density showed that plants removal was most effective on the number pods per unit area followed by seed number per plant and single-seed weight. The potential of the plants to offset plant deficiency by increasing pod number per plant was decreased by retarding plants removal from vegetative to reproductive growth stage.