Effects of Sowing Date on the Growth and Yield of Direct Seeding Sorghum of Different Varieties

PurposeSorghum is the main raw material of Chinese liquor, the yield of which is affected by ecological condition of growth period greatly. Direct seeding, one of most important simplified cultivation ways is more and more popular. This study was conducted to elucidate the effect of sowing date on growth and grain yield of direct seeding sorghum, expecting to provide a reference for high-efficient production of direct seeding sorghum in the Southwest China.

MethodFive sorghum varieties mainly grown in Southwest China were used as materials, and five sowing dates were designed. The emergence rate, growth stage, photosynthetic characteristics and yield were measured and the correlation between these characters above and ecological factors was analyzed.

ResultSowing date had a significant effect on the growth and yield of sorghum, with similar trend but different extent of variation among cultivars. Along with the delay of sowing date, the emergence rate of direct seeding sorghum increased significantly, and the growth stage shortened, primarily causing by the lessening of days between sowing and heading. The SPAD of top three leaves and LAI in heading stage both increased firstly and then declined. The seed setting rate, 1 000-grain weight, grain weight per ear and yield all decreased with the delay of sowing date. There were highly significant positive correlations between emergence rate and average temperature, effective accumulative temperature and rainfall of 7 days after sowing. The growth stage and yield of sorghum had highly significant negative correlations with average temperature of the period before heading and the whole growth stage.

ConclusionCompared with sowing late, sowing early had the advantages of longer growth stage, higher yield, but the disadvantage of lower emergence rate. The suitable sowing date was recommended between April 15th and May 2nd for direct seeding sorghum in Southwest China.