Growth, nodulation and yield responces of promiscuous and specific-nodulation soybean cultivars to rhizobium inoculation and seaweed extract

Soybean (Glycine max L.) is one of the valuable leguminous crops with grain used for human consumption, livestock feeding, bio-fuel (bio-diesel) production, vegetable oil and is a protein resource. The crop also fixes atmospheric nitrogen. The study aimed to evaluate the performance of two soybean varieties to a combination of inoculation and seaweed extract. The research trial was conducted at Syferkuil farm during 2017/2018 summer season in which two soybean varieties (TGx 1937-1F promiscuous) and (PAN 1583R specific-nodulating) were evaluated for their growth, nodulation and yield responses to rhizobium inoculation and seaweed extract (0 % rate (0ml/12L), 50 % rate (30ml/12L) and 100 % (60ml/12L). The research trial was laid out as a split-split plot arrangement fitted in RCBD with four replications. Inoculation significantly influenced grain yield at P≤0.05, seed nutrient content and total above-ground biomass, except for seed potassium. No inoculation significantly achieved higher primary branches per plant at P≤0.05, pod number per plant, stem diameter (P≤0.05), grain yield (P≤0.05), harvest index and total above-ground biomass at P≤0.001. The variety TGx 1937-1F had significantly (P≤0.001) higher nodule number per plant, effective nodules per plant, nodule dry weight, dried shoot biomass, leaf number per plant, pod number per plant, primary branches per plant, stem diameter, plant height, leaf chlorophyll content, total above-ground biomass, grain yield and seed iron (Fe) content. Application of full rate seaweed extract significantly (P≤0.001) increased primary branches per plant, stem diameter, leaf number per plant, plant height, shelling percentage, total above-ground biomass, grain yield, and seed content of calcium (Ca), potassium, magnesium (Mg), manganese (Mn) and sodium (Na) all at P≤0.05. Seaweed extract rate at 0 % obtained the highest harvest index (P≤0.001). Inoculation and variety TGx 1937-1F interaction exhibited a significant increase on leaf
National Research Foundation (NRF)