Effects of planting date on agronomic performance and yield of two Bt corns in Mississippi Delta. 

Planting date is a critical decision for corn farmers to make each year. Current recommendations suggest that corn should be planted between mid-March and mid-April for the Mississippi Delta. However, due to various practical reasons, many farmers may not be able to plant corn in optimum planting window. Limited information is available in how Bt corn hybrids respond to non-optimum planting date. This is important in many aspects for corn farmers to make critical planting decisions. We have conducted a study to investigate how Bt corn respond to different planting dates. Experiment was conducted on the Delta Research and Extension Center at Stoneville Mississippi. Two Bt corn hybrids, one early and one late, were used. Four planting dates were used from early March to mid May with approximately three weeks apart. Phenological, morphological and final yield were collected and analyzed to determine if and how the planting dates affect on yield performance of Bt corn. Results indicated that early planting dates are still favored due to physiological advantages of growth and development.  However, yield were the highest for later-March planting, though no statistical difference found compared with early-March planting. Early March planted corns had a chilling injury resulting in some damage in early development of corns, but recovered later.