Observational Study on the Recovery from Root Lodging at Flowering Time and Yield Reduction in Maize (Zea mays L.)

On August 2, 1999, the typhoon “Olga” with the maximum wind speed of 19.2 m/s hit the Korean peninsula and caused considerable damage to crops. Regional yield trials were at tasseling stage and were affected by the typhoon. After the storm, almost all the plants were root-lodged. This provided a rare chance to study the relationship between recovery from the lodging and reduction of grain yield in maize. Three check cultivars were examined for angle of lodging, grain yield, yield components, plant height and ear height. Six levels of leaning were classified. Plants leaning less than 10o from the vertical were considered as non-lodged. Average reduction in grain yield across five levels of lodging was 29.2% with the mean of 46.1o. The reductions of three hybrids were 25% for Suwon 19, 39.5% for Pioneer 3525 and 27.4% for DeKalb 689. R2 values of grain yield on angles of lodging ranged from 0.33 for Suwon 19 to 0.51 for Pioneer 3525. The slope of the regression was lowest for Suwon 19 and highest for Pioneer 3525. Yield reduction from lodging was less severe for the locally bred Suwon 19. Reductions in yield components were also influenced by cultivars with Pioneer 3525 showing the most severe reduction. The yield components most severely affected by root lodging at the flowering time were ear length and number of kernels per row. The high reductions in yield and agronomic traits caused by root lodging justify the lodging resistance as a major breeding objective in Korea.