Biochar Application from Different Feedstocks Enhances Plant Growth and Resistance against Meloidogyne incognita in Tomato

Activated charcoal (biochar) is well known as carbon sequestering compound which acts as plant growth promoter and suppressor of soil borne pathogens. Tomato plant is affected by number of microbial pathogens including root-knot nematodes (RKNs) which belongs to genus Meloidogyne. Meloidogyne incognita is one of the most devastating pests infecting tomato roots and causes significant losses in quality and quantity. To manage these losses new strategies are required to be developed and adopted to strengthen plant growth and control RKNs populations in the soil. Current study was designed with the hypothesis that biochars from different feedstocks may lead to increased resistance against Al incognita in tomato. For this purpose, biochars from three different feedstocks i.e., wheat straw (WS), rice husk (RH) and sugarcane bagasse (SCB) were evaluated for their potential against M. incognita under in vitro and pot trials. Surface structure analysis of all the biochars was done using Scanning Electron Microscope (SEM) and substance structure analysis through x-rays diffraction (XRD). Five different concentrations of exudates (0.3, 0.5, 1.2, 2.3 and 3%) from all three biochars were assessed under in vitro conditions for their nematicidal efficacy. The exudates of the selected biochars at different levels were directly applied on freshly hatched juveniles but there were no direct toxic effects of biochar exudates on nematodes mortality observed. Similarly, three different concentrations viz., 2, 3 and 5% along with positive control (+Nematode) and negative control (-Nematode) were added to the tomato plants in pot experiment. Among all concentrations 3% RH biochar exhibit significant improvement in plant morphological traits like shoot length, shoot fresh weight and dry weight. Similarly, number of galls, egg masses and number of females were also reduced maximum in 3% RH treated plants as compared to control. While root length, root fresh weight and root dry weight were increased in 5% SCB. The results demonstrate the significance of biochar application for controlling RKNs in tomato and other crop plants. (C) 2020 Friends Science Publishers