Studies on the effect of bioinoculants, plant growth regulators and humic acid on growth and flower yield of African marigold (Tagetes erecta) under walk-in tunnel

The present study, entitled “Studies on the effect of bioinoculants, plant growth regulators and humic acid on growth and flower yield of African marigold (Tagetes erecta) under walk-in tunnel”, was carried out at the Centre of Excellence, Protected Cultivation and Precision Farming, College of Agriculture, Indira Gandhi Krishi Vishwavidyalaya, Raipur (C.G.) during 2024-25 Rabi season. The experiment was laid out in a Factorial Randomized Block Design with 12 treatments of two factors and replicated three times. The treatments consisted of three levels of soil drenching: no drenching (SD₀), PSB 10% (SD₁), and KSB 10% (SD₂), and four levels of foliar application: no spray (FS₀), humic acid 0.2% (FS₁), GA₃ 200 ppm (FS₂), and NAA 50 ppm (FS₃). The study found that applying Phosphorous Solubilizing Bacteria (PSB) through soil drenching at 10%, GA3 200ppm as a foliar spray and especially their combined treatment (T7: PSB @ 10% + GA3 200 ppm) performed best with regards to early 50% flowering, minimum number of days to full bloom, flower yield per hectare, flower diameter, fresh weight of flowers per plant, dry weight of flowers per plant, flowering span and shelf life in African marigold.