Effect of High Temperature Stress on Pollen Grains in Sunflower (Helianthus annuus L.) Inbred Lines

: High temperature at reproductive stage causes a decrease in seed set that ultimately results in yield loss in important crops. Limited research is available regarding the effect of high temperature on viability attributes of pollen grain in sunflower. This study was planned to reveal the effects of high temperature stress on pollen grains in sunflower. An experiment was laid out in a triplicated Completely Randomized Design with split-split plot arrangements at the Oilseeds Research Institute, Ayub Agricultural Research Institute Faisalabad during spring 2021. Two temperature treatments T1 = 45° C for 10, 20 and 30 minutes, and T2 = 50° C for 3, 5 and 10 minutes were used on 10 sunflower inbred lines. Normal (untreated)