Lodging in maize results in grain yield reduction. This experiment investigated the effects of different application rates of the growth retardant, uniconazole (UCZ), and nitrogen (N) on medium and high maize population densities on lodging resistance and yield. UCZ was applied to maize seeds at concentrations of 0 (U0 ) and 25 (U25 ) mg kg-1 , and three different N application rates, 0 (N0 ), 150 (N150 ) and 225 (N225 ) kg ha-1 , at plant densities of 75,000 (D1 ) and 105,000 plants ha-1 (D2 ). UCZ application, different N rates and plant population density affected the lodging resistance and yield attributes of maize. The diameter, plumpness, cortex penetration and bending strengths of the internodes were enhanced with UCZ and N application at medium and high plant density, where maximum values were obtained with U25 N150 D1 . Internode length increased in the high-density population and higher N rate, whereas UCZ reduced internode length, where maximum internode length was obtained with U0 N225 D2 . Plant height, centre of gravity height, ear and height above ear-bearing node were higher with the high N rate, while UCZ reduced it significantly. UCZ, N rate and plant density enhanced lignin accumulation in the third internode and ear-bearing internode, where maximum values were obtained with U25 N150 D1 . Yield and yield attributes were also improved by UCZ, N rate and population density. Treatment with U25 N150 D2 significantly improved grain yield of maize compared with the other treatments.
Keywords: lodging resistance; maize; nitrogen application; plant density; uniconazole.
© 2021 German Society for Plant Sciences and The Royal Botanical Society of the Netherlands.