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Manipulation of the canopy structure in such a way that it would be able to intercept as much light as possible to maximize photosynthesis is one of the
most important ways of increasing crop production. To determine the role of stem reserves in the filling of car under the conditions of reduced current
photosynthesis, the present investigation was conducted in a complete randomized block design with four replicates and at Kushkak Agricultural Research Farm of Shiraz University. The results showed that removal or all blades' apical half in tassel complete emergence.: stage. increased the grain
yield by up to 21 %. This might have been the result of the greater light penetration. Complete defolition lion in 20 days after silk completely emerged
(SCE), reduced grain yield by 52%. However. the removal or tassel and all leaves above the car, except the nearest leaf to the car. in 1 () days after SCE,
had no effect on grain yield. Complete defoliation, on the other hand. significantly reduced final stem dry weight and its diameter. indicating an
increase in remobilization or assimilates from stem to the car.