Abstract

Seven different strains of Trichoderma isolated from wilt infected legume fields of UP State were tested for their antagonistic activity against Fusarium (soil borne pathogen), which is expressed as a zone of inhibition in the culture plates. Seven strains were identified as Trichoderma viride, Trichoderma harzianum, Trichoderma asperellum, Trichoderma koningii, Trichoderma atroviride, Trichoderma longibrachiatum and Trichoderma virens. Upon successful identification, morphological description and sequencing of the isolated strains with the help of universal Internal transcribed spacer (ITS) primers, the sequences are submitted to NCBI and allotted with the accession numbers JX119211, KC800922, KC800921, KC800924, KC008065, JX978542 and KC800923, respectively. Mycoparasitism is an inherent ability of the genus Trichoderma that involves the role of cell wall degrading enzymes such as xylanase, glucanase, chitinase, and proteinase etc. and acting as a biocontrol agent. This study reports the xylanase enzyme activity for all the isolated strains on a media containing birchwood xylan as a carbon source where T. harzianum (Th Azad), could show maximum activity there upon acting as a strain of utmost importance to the farmers for protecting their crops against wilting. Genetic variability within different strains of the same species was also analyzed to develop a novel strain possessing competitive ability, growth promoting characters and inducing resistance in plants. A percentage of polymorphism in Simple sequence repeats (SSRs) is obtained within the seven strains of Trichoderma species, which is comparatively higher (>77%) than with Random amplified polymorphic DNA (RAPD) primers (~50%). The study aims at exploring Trichoderma species and then preparing a simple bioformulation that is cheap, easy to apply and readily accessible to the farmers. The shelf life of Trichoderma in the prepared bioformulation is even checked for 180 days and it is concluded that the number of propagules start declining from 30^th day onwards when the bioformulation is prepared in talc as a carrier material. It was also found that seed treatment with the bioformulation T. harzianum (Th Azad) (5 g/kg seeds) could increase seed germination, root and shoot length and seedling vigour over untreated ones.

Key words: Antagonism, bio-control agent, Trichoderma, shelf life, polymorphism, genetic variability.