A Combined Nutrient/Biocontrol Agent Mixture Improve Cassava Tuber Yield and Cassava Mosaic Disease

Cassava (Manihot esculenta Crantz) is an important tropical root crop and a major dietary energy source for more than 500 million people. The major production constraints in cassava are the occurrence of nutrient deficiency and cassava mosaic disease (CMD). Hence to increase the cassava yield, it is critical to develop a technology to overcome the problems associated with nutrient deficiencies and CMD. Series of field experiments were conducted to evaluate and validate a new mixture containing biocontrol agent and nutrients on different genotypes and locations. The result indicated that foliar spray of combined nutrient/biocontrol agent mixture at 21 d interval from one to five-month after planting (MAP) had significantly decreased the incidence of nutrient deficiency symptom and CMD incidence resulting in an increased tuber yield. There were significant differences among the cassava genotypes for CMD reaction and foliar spray of combined nutrient/biocontrol agent mixture at 21 d interval from 1 to 5 MAP. The genotype H226 had lower CMD incidence and higher tuber yield. The multilocation trial indicated that foliar spray of combined nutrient/biocontrol agent mixture at 21 d interval from 1 to 5 MAP significantly improved the tuber yield (24%) and decreased the CMD incidence (65%) than unsprayed control. Metabolomic study indicates that foliar spray of combined nutrient/biocontrol agent mixture has altered lipid biosynthesis and metabolism, as evidenced by increased accumulation of octadecatrienoic acid (2.28-fold) trilinolein (126.3-fold) in combined nutrient/biocontrol agent mixture sprayed plants over unsprayed control. Overall, it is evident that foliar spray of combined nutrient/biocontrol agent mixture from 1 to 5 MAP has decreased CMD incidence and increased the tuber yield.