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.