Effect of sowing date on growth and yield of spring-maize

Two sowing dates (April 24 and May 15) and two genotypes (“Zhengdan958” and “Ludan984”) were used to investigate the effect of meteorological change on the growth, development and yield of spring-maize. The results indicate significant differences in the growth and yield of spring-maize under different sowing dates. Yield of spring maize sown on May 15 increases by 2 157 kg·hm^-2 for “Zhengdan958” and 1 137 kg·hm^-2 for “Ludan984” than those sown on April 24. 1000-grain weight difference between two sowing dates and genotypes are insignificant. Difference in grain number per ear-corn is insignificant between the two genotypes, but significant between the two sowing dates. Grain number per ear-corn for spring-maize sown on May 15 increases by 37.8％ in “Zhengdan 958”and 11.2% in “Ludan 984” over those sown on April 24. Kernel number decline constitutes the main reason for low grain yield in spring maize which is driven by climatic factors. Precipitation affects yield by decreasing kernel number. Low temperature and solar radiation, due to high precipitation during flowering, leads to low pollination, hence low kernel number. Also the lack of dry matter accumulation as a result of low precipitation during 6-to-12-leaf stage affects kernel development. Thus May 15 is a better sowing date for the high yield. Determining appropriate sowing date and reducing the negative effects of precipitation on yield are key factors for high yield spring-maize in North China Plain.