Abstract: In order to determine the suitable sowing time and planting density of the newly bred sweet sorghum sterile lines, this experiment taking the sweet sorghum sterile lines TX623A and 7050A as the control and the newly bred sorghum sterile lines 29A, 34A and 44A as the experimental materials, set three sowing dates and three planting densities by split plot experiment, and analyzed their effects on the yield and yield-related characters of the newly bred sweet sorghum sterile lines. The results showed that different sowing dates and planting densities had significant differences on 1 000-grain weight. The suitable sowing date for 29A and 34A was May 14th, with a density of 80 000 plant/hm², and the suitable sowing date for 44A was April 30th, with a density of 80 000 plant/hm². Different sowing dates and planting densities had significant differences on the number of grains per panicle. When sowed on April 30th ,with the density of 70 000 plant/hm², the number of grains per panicle was the largest, and the number of grains per panicle in 34A and 44A was larger than that of TX623A and 7050A as control varieties. The effects of different sowing dates and planting densities on economic yield and biological yield were significantly different. The yield of 29A, 34A and 44A showed a decreasing trend with the delay of sowing date and the increase of density, and the economic yield showed a very significant correlation with yield traits. Based on the above results, when 29A, 34A and 44A were sown on April 30th,with the density of 75 000 plant/hm², the yield of sterile lines was the highest. This experiment provides cultural technical support for the production of newly bred sweet sorghum sterile lines.

Key words: sweet sorghum, yield, sowing date, density, male sterile line