Effects of paclobutrazol application on plant architecture, lodging resistance, photosynthetic characteristics, and peanut yield at different single-seed precise sowing densities

The key to high-yielding peanut cultivation is the optimization of agricultural production practices. Regulating single-seed precise sowing (SSPS) density and paclobutrazol (Pbz) application concentration are effective practices that increase peanut yield by improving plant architecture, lodging resistance, and photosynthetic characteristics. Therefore, we conducted a two-factor field optimization experiment for the sowing density (D1: 1.95 × 105 plants ha−1, D2: 2.40 × 105 plants ha−1, D3: 2.85 × 105 plants ha−1, and D4: 3.30 × 105 plants ha−1) and Pbz application concentration (P0: 0 mg L−1 and P1: 100 mg L−1). The objective was to optimize agricultural production practices and provide a theoretical basis for high-yielding peanut cultivation by evaluating the effects of sowing density and Pbz application on plant architecture, lodging resistance, photosynthetic characteristics, and yield. The results showed that at the same Pbz application concentration, increasing sowing density increased lodging percentage and reduced leaf photosynthetic capacity. At the same sowing density, Pbz application reduced lodging percentage by decreasing plant height (PH), improving lignin biosynthesis-related enzyme activities, and enhancing stem puncture strength (SPS) and breaking strength (SBS). The paclobutrazol-induced alterations in plant architecture and lodging resistance improved light transmission at the middle and bottom leaf strata, resulting in the increase in relative chlorophyll content and net photosynthetic rate (Pn) of leaves. Furthermore, D3P1 treatment had the highest peanut yield among all treatments. In summary, the production strategy combining the sowing density of 2.85 × 105 plants ha−1 with the application of 100 mg L−1 Pbz was found to be the optimal agricultural production practice for giving full play to production potential and achieving higher peanut yield.