Phenology, yield and protein content of maize (Zea mays L.) hybrids as affected by different sowing dates.

The optimum sowing time and the suitable hybrid are agronomic management practices that play a major role in determining the quantity and quality of maize yield. In this study, a randomized field experiment was established at ARDS Simnic, Craiova to assess the influence of sowing dates and hybrids on phenology, grain yield and protein content of maize. The research included three sowing dates: 9th April, 16th April and 23th April. The results showed that the delayed sowing dates had higher impacts on the phenology of maize, shortened the all plant growing stages and reduced the accumulated heat units (GDD), especially after the silking stage. In early sowing date (9th April), the grain yield (GY) and heat use efficiency (HUE) were significantly higher compared to two other sowing dates, for all hybrids. Protein content of maize grain increased with delay in sowing date due to the modifications of thermal conditions during grain-filling period. Maize hybrids PR39D81 and LG3350 that produced the maximum grain yield (11.47 t/ha and 11.42 t/ha, respectively) when sown in 9th April, were the most suitable hybrids for this region.