Prohexadione calcium applications increase peanut peg strength

Prohexadione calcium is a growth regulator, which manages excessive vine growth in peanut (Arachis hypogaea L.) by reducing shoot internode length. To test the effect of prohexadione calcium on peanut, a field experiment was conducted at the West Florida Research and Education Center in Jay, FL, during 2021 and 2022. The objective was to determine peanut response at different rates (untreated control, 70, 105, 140, and 175 g a.i. ha⁻¹ of prohexadione calcium). Data were collected on yield, peg strength, above- and belowground biomass, plant height, and total sound mature kernels. Additionally, return on investment for prohexadione calcium application was also calculated. Prohexadione calcium application resulted in significant reduction of peanut plant height. The application rate of 105 g a.i. ha⁻¹ resulted in significantly greater normalized difference vegetation index as compared to untreated control. Belowground, aboveground, and total biomass did not significantly differ between the 140 g a.i. ha⁻¹ rate and untreated control. However, peanut peg strength increased significantly at the 140 g a.i. ha⁻¹ treatment compared to the untreated control. Peanut yield ranged from 6.65 to 7.15 Mg ha⁻¹ among different treatments; however, the differences among treatments were not significant. Similarly, the total sound mature kernels and return on investment did not differ significantly under different prohexadione calcium treatments. Considering that peanut response to prohexadione calcium is difficult to observe in small plots, it is important to test the effect of prohexadione calcium on peanut production under on-farm large plot conditions.