اثر شدت حذف برگ در مراحل مختلف رشد زايشي بر عملكرد دانه و روغن آفتابگردان (Helianthus annus L)

Effect of defoliation intensity at different reproductive stages on seed and oil yields in sunflower (Helianthus annus L.)

In order to determine the effect of defoliation intensity at different reproductive stages in sunflower tHelianthus annus L.) on seed and oil yields, and determining the most sensitive reproductive stages to defoliation, a field experiment was conducted at Tarbiat Modares University Research field using a split plot arrangement in a ReBD with four replications in 2007 cropping season. Main plots consisted of defoliation at four reproductive stages including: star shape of inflorescence stage (Rl ), pollination stage (R5), seed setting initiation (R6), and end of grain filling (R7). while five defoliation intensities (0% as all undefollated control, 2Y~·O, 50%, 75% and level removed 100%) were arranged in sub-plots. The results indicated that defoliation time and intensities had significant effects on all traits. The interaction of two factors significantly (P