Effect of uniconazole and nitrogen level on lodging resistance and yield potential of maize under medium and high plant density

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 (U-0) and 25 (U-25) mg kg(-1), and three different N application rates, 0 (N-0), 150 (N-150) and 225 (N-225) kg ha(-1), at plant densities of 75,000 (D-1) and 105,000 plants ha(-1) (D-2). 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 U25N150D1. Internode length increased in the high-density population and higher N rate, whereas UCZ reduced internode length, where maximum internode length was obtained with U0N225D2. 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 U25N150D1. Yield and yield attributes were also improved by UCZ, N rate and population density. Treatment with U25N150D2 significantly improved grain yield of maize compared with the other treatments.

Automated summary

In maize, lodging due to high density planting can lead to reduced yields. However, using growth retardant UCZ and nitrogen fertilizer at high densities can improve lodging resistance and yield attributes, affecting internode growth and plant height. UCZ significantly influences lignin accumulation in internodes, while treatment with U25N150D2 shows better improvement in maize grain yield.