The bracteal leaf, the nearest "source" to the "pool" of grain, increases the photosynthetic area and efficiency of sunflower and its removal reduces the grain yield by 1.9-7.6% in an edible variety and by 1.8-5.1% in a high oil one. Except for the mechanical injury when the bracteal leaf is removed, the effects of pruning off the bracteal leaf on grain yield agreed with Pereita's (1978) results who stated that 5% of grain yield were supplied by the ten leaves located on the basal part of the sunflower stem. Measures should be tâken to promote and safeguard the growth of the bracteal leaf. Selection for the area of the bracteal leaf and gradient and size of flower disc should also be conducted in breeding programs. According to A.N.RYTAEB the area of the bracteal leaf is â quantitative trait which can be set as an objective and improved in a sunflower breeding program.