Effect of soybean seed treatment with Trichoderma virens on its growth and total phenolic content

Abstract

Trichoderma spp. are well known as soil inhabitant and saprophytic fungi. These fungi are utilized as biocontrol agents to suppress plant pathogens as well as plant growth promoters of many crops. The effects of T. virens conidia application as a seed coating on the growth of soybeans were investigated in the present study. The application of seven isolates of T. virens influenced the germination of soybean seeds. Numbers of normal germinate seeds varied from 64% to 84%. Root length was also affected by the colonization of T. virens. The root lengths of the treated seeds were from 21.8 cm to 29.3 cm, whereas the control was only 21.1 cm. Only several isolates influenced the shoots which were higher than that of the control. All isolates increased the weight of the roots. The weight of shoots was not significantly influenced by the isolates. The seven isolates were able to colonize the roots and the growth of all isolates on potato dextrose agar was from 3 to 6 days after the roots were surface sterilized. Secondary metabolites particularly total flavonoid and phenolic contents of soybean seedlings were also affected. The increases were from 1.6% to 9.4% and from 4.0% to 25.6% for total flavonoid and phenolic contents, respectively. Peroxidase activities were not much affected by all isolates. The T.v3 isolate was considered for the growth promotion of soybean seeds.