Response of Cassava Root Manihot esculenta to Potassium-Rich Biostimulants Manufactured from Red Seaweed Gracilaria salicornia Under Semi-Arid Condition

Abstract

Seaweed extracts are proven to be potent biostimulants due to the presence of wide range of nutrients including mineral like potassium and other macro-micronutrients, plant growth hormones, amino acids, vitamins, glycine betaines and quaternary ammonium compounds in them. In the present study, potassium-rich powders were obtained from some commercially important tropical red seaweeds viz. Kappaphycus alvarezii, Gracilaria salicornia, G. edulis, G. firma and G. heteroclada and Eucheuma spinosum and checked for their biostimulant effect through green gram seedling bioassay study on in vitro using WinRhizo software, and we found that extracts of all species increased the root development at significant level (p < 0.05) as compared to standard nutrient medium. G. salicornia of Indian origin which is naturally available on a commercial level (>1000 t dry per year) was taken for further studies and manufactured 3 variants of potassium-rich biostimulants, viz. concentrated seaweed extract (CSE), potassium-rich water-soluble powder (PSP) and seaweed fortified granule (SFG), and tested their biostimulant activity on cassava root at farmer’s field and found to increase the tuber yield to 17.40%, 20.09% and 22.19%, respectively, with high starch content, less incidence of cassava brown streak virus disease (CBSD) and increased nutrient use efficiency over control plants. Based on the results of present study, potassium-rich biostimulant obtained from G. salicornia can be applied to cassava for yield and quality improvement.