Trichoderma asperellum spore dose depended modulation of plant growth in vegetable crops.

In the present study we bioprimed seeds of six vegetable crops (tomato, brinjal, chilli, okra, ridge gourd and guar) with different spore doses of Trichoderma asperellum BHUT8 ranging from 102 to 108 spores ml-1 and the effect of biopriming was seen on seed germination and development. The most effective spore dose for enhancement in seed germination and radicle length was found to be 103 spores ml-1 in tomato and ridge gourd, 104 spores ml-1 in brinjal and okra while 106 spores ml-1 in chilli and guar. At the most effective spore dose, the increase in germination percentage was 5, 146.15, 112.5, 5.4, 28.13 and 0% while increase in radicle length was 73.17, 50.83, 171.6, 107.35, 247.19 and 90.79% in tomato, brinjal, chilli, okra, ridge gourd and guar, respectively, compared to their controls. Higher spore dose i.e. 107-108 spores ml-1 and 106-108 spores ml-1 in tomato and brinjal, respectively, reduced seed germination percentage and radicle growth compared to their controls. Biopriming with T. asperellum BHUT8 also triggered various defense like responses such as high phenylpropanoid activities and lignifications in bioprimed tomato seedlings compared to the non-bioprimed tomato seedlings demonstrating possible use of BHUT8 against phytopathogens.