Growth and biomass production of Gongronema latifolium (Benth) using substrate mix with biochar inclusion and pinching regimes in southeast Nigeria

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This research demonstrated the possibility of growing and producing Gongronema latifolium using various substrate mixes and pinching regimes. The greenhouse experiment was conducted at the Research and Teaching Farm of the School of Agriculture and Agricultural Technology, Federal University of Technology Owerri, Nigeria, during the 2023 late-season farming period. The experiment followed a 4 x 3 factorial design in a Completely Randomized Design (CRD) and was replicated thrice. The factors were four substrate mixes (sawdust/poultry manure/biochar mix in the ratios of 3:2:0, 3:2:1, 3:2:2, and 3:2:3) and three pinching regimes (2, 4, and 6 weeks after transplanting). The substrates (sawdust, poultry manure, and ground biochar) were procured, composted, and cured for 2 weeks before mixing. The measurements were made in volume (v:v:v:v). The substrate mix was introduced into perforated black polybags of 11 cm x 13 cm size and 1 mm thickness. The filled polybags were watered and allowed 2 days for thoroughly binding the substrate mix. Seedlings from the nursery trays were then transplanted into the polybags filled with the substrate mix. Seedlings transplanted at 6 weeks of age were pinched with fingernails at the tip of the plant below the second leaf at 2, 4, and 6 weeks after transplanting, as per the experimental design. Staking, water application, and weeding were carried out at appropriate times. Data on growth and biomass production were collected. Growth and biomass production results showed significant (P<0.05) differences. Substrate mixes of 3:2:3 and 3:2:2 optimally improved growth and biomass production (number of leaves, leaf area, vine length, branches, and fresh and dry shoot weight). Pinching regimes at 4 and 6 weeks produced more leaves and branches, resulting in a larger quantity of fresh and dry shoot biomass of G. latifolium. Furthermore, the interactions of 3:2:3 + 6 weeks and 3:2:2 + 4 weeks recorded optimal leaves and fresh and dry biomass yields. As shoots and leaves are the economically significant components of the plant, pinching regimes at 4 and 6 weeks and the 3:2:3 + 6 weeks and 3:2:2 + 4 weeks are advised for farmer adoption. This method can increase vegetable output and assist in lowering world poverty.