EN

Abstract

The experiment was conducted in spring 2014 to evaluate the effect of defoliation on the quantitative and qualitative characteristics of sugar beet in Motahari research station located in the Kamal Shahr region in Karaj, Iran. The study was conducted in split plot factorial with completely randomized block design with four replications. The main factors included two planting dates viz 23 April, 2014 (suitable planting time) and 18 May, 2014 (Late planting) and the sub-factors included five levels of defoliation including stage of early cotyledon growth to two true leaves (2 leaves), the stage of plant deployment (about 12 leaves), mid-growth (about 32 leaves) and late season of growth (about 54 leaves) and another sub-factors included five levels of defoliation intensity of leaves included 25%, 50%, 75% and 100% of defoliation and non-defoliation stage (control) as randomized and factorial were considered. Result of study revealed that different planting dates have significant effect on the sugar percentage of root. In addition, the treatment of defoliation stage could have a significant effect on root yield and white sugar yield (p>0.01).The treatment of defoliation intensity had a significant effect on all three traits (p>0.01). In general, increase in the defoliation intensity negatively affects the root yield and significantly reduced the white sugar yield (compared to control). Among the various stages of defoliation, middle stages of the defoliation have least effect on the evaluated traits which indicated more sensitivity of this treatment during the growing season of plant.