Abstract:Sowing date and density are the two main factors affecting the yield and quality of sunflower. Suitable sowing date and planting density are important guarantees for high-yielding and high-quality sunflowers. In this paper,field experiments were conducted using the main sunflower varieties KWS303 and SH363 in Xinjiang to investigate the effects of different sowing dates and densities on the growth process, plant morphology, and yield of sunflowers.Delayed sowing accelerated the emergence of sunflower seedlings and shortened the whole growth period. Within a certain range, the plant height of sunflower increased with the delay of sowing date and the number of green leaves and stem diameter of main stem increased with the delay of sowing date and filling stage, but the effect on disk diameter was small. With the increase of the density at the same sowing date, the number of green leaves and diameter of the thick disk of the main stem decreased at the filling stage, and the yield of the two varieties was the highest under the double factor of sowing date density or the effect of sowing date density.