Influence of 3-Methylthiopropionic Acid (MTPA) Produced by Rhizoctonia solani AG-3 on Yield and Dry Matter Accumulation of Potato

Studies were conducted to investigate the effect of 3-methylthiopropionic acid (MTPA) produced by Rhizoctonia solani AG-3 on yield and dry matter accumulation of potato. The experiments were laid out in a completely randomized design with five treatments and five replications. The treatments were 0, 1, 2, 4 and 8 mM concentrations of MTPA. Results showed that the MTPA phytotoxin reduced plant growth and tuber yield, compared to the control. Plants treated with 8.0 mM MTPA significantly reduced aboveground fresh weight and belowground fresh weight by 260.14% and 395.95%, respectively, compared to the control. Plants treated with 8.0 mM MTPA significantly reduced tuber yield by 419.12% compared to the control. Application of 8.0 mM MTPA also significantly decreased fresh weight of individual tuber by 100.22% in comparison with control plants without MTPA phytotoxins. Treatment of plants treated with 8.0 mM MTPA increased biomass of potato plants by 112.44%. Cankers were seen on the potato seedling stems treated with 3-methylthioproprionic acid with 8.0 mM MTPA producing the highest stolon and stem canker of 97.78% and 97.10%, respectively. Compared with untreated control, black scurf incidence of potato plants treated with the phytotoxin at a rate of 8 mM was increased by 94.59%. The study demonstrated that R. solani phytotoxin can induce stem canker and black scurf development resulting in yield reduction of potato plant.