Abstract: The filling characteristics of confectionery sunflower(Xianrui 12)under different densities were studied and fitted by Richard equation.The results showed that under the same density and different tillage methods,the yield increased with the increase of density,and the yield under S45 treatment increased by 6.3%and 10.3%relative to the yields of S30 and RT,respectively,and the yield of S30 was 3.8%higher than RT.Under the same tillage pattern,the density of D3 increased by 28.1%and 17.0%compared with D1 and D2,respectively and D2 increased 9.4%compared with D1.Grain filling rates(GRmean)of sunflowers with different grain positions,the initial growth potential(R0),the time of maximum grain filling rate(Tmax)were outer edge grain>middle grain>inner grain.Under different tillage methods,S45 was the highest;S30 was the second and RT was the lowest.R0 and GRmean decreased with the increase of density at different densities.The time of maximum grain filling rate(Tmax)of outer grain was earlier than that of inner grain.Subsoiling accelerated grain filling and shortened grain-filling time.The I value of outer grain was higher than that of either inner grain or middle grain.Subsoiling improved GRmean and R0 of sunflower seeds and promoted the seed filling of sunflower.

Key words: Sunflower;Subsoiling;Density;Grain filling