Management Effects on Yield and Yield Components of Late‐Planted Wheat

Intensive cereal management can increase the yield and performance of winter wheat ( Triticum aestivum L. emend. Thell.), but wet soils often delay planting along the Gulf Coast. Field experiments were conducted at four locations in 1991 and two locations in 1992 to evaluate the effects of two seeding rates (84 or 168 kg ha −1 ) and two. topdress N rates (90 or 90 + 45 kg ha −1 ) for an early and late‐maturing cultivar planted at a recommended date or 35 d later. Main effects were generally more significant than interactions except for those involving environment (year‐location). Late planting resulted in significant reduction in grain yield even though more spikes per square meter were produced. Wheat kernels from the recommended planting date were heavier and each spike contained more kernels, which resulted in higher grain yield. Additional N significantly increased yield when the crop was planted at the recommended date by increasing kernels per spike and spikes per square meter, but did not increase yield of the late‐planted crop. Grain yield was not affected by seeding rate for the early planted wheat. Seeding rate effects were influenced by the environment for late planting; however, there was evidence that the higher seeding rate increased yield of the late‐planted crop. Delayed planting reduced yields due to a decrease in kernel weight and kernel number per spike, but the magnitude of yield loss was reduced by using an early‐maturing cultivar and a higher seeding rate.