NARDI FUNDULEA, ROMANIA ROMANIAN AGRICULTURAL RESEARCH, NO. 38, 2021 www.incda-fundulea.ro Print ISSN 1222‒4227; Online ISSN 2067‒5720 ________________________________________ Received 21 September 2020; accepted 2 February 2021. First Online: February, 2021. DII 2067-5720 RAR 2021-30 INVESTIGATION OF BIOLOGICAL CONTROL OF TRICHODERMA FORMULATIONS AND ITS MUTANT TYPE RELATED TO CHEMICAL TREATMENTS IN THE CONTROL OF SOYBEAN CHARCOAL ROTS DISEASE Soheil Orojnia 1 , Davood Habibi 1* , Samira Shahbazi 2 , Farzad Paknejad 1 , Mohammad Nabi Ilkaee 1 1 Department of Agronomy, Islamic Azad University, Karaj branch, Karaj, Iran 2 Nuclear Science and Technology Institute, Atomic Energy Organization, Karaj, Iran * Corresponding author. E-mail: d_habibi2004@yahoo.com ABSTRACT In order to study biological control of soybean charcoal rot disease using multiple mutant Trichoderma formulations with gamma ray, an experiment under greenhouse conditions was performed in the years 2017 and 2018 at Karaj Nuclear Agriculture Research Institute. Beside control the experiment consisted of 16 treatments including chemical and commercial fungicides and inoculation of mutant and non-mutant soybean with Trichoderma fungi. The results showed that the effect of treatments was significant for all morphological and physiological characteristics of soybean. The use of Trichoderma treatments had a positive influence on plant morphological characteristics such as pod number, stem dry weight, stem length, number of branches and physiological traits such as peroxide, chlorophyll a, chlorophyll b and carotenoids. As a result, they increased the yield so that the highest average of 11.75 g per pot was registered to the seed coating treatment with wild Trichoderma (PW). The use of fungal treatments increases proline and malondialdehyde content and the incidence of disease is reduced by using Trichoderma. Keywords: biological control, gamma ray, mutant Trichoderma, soybean charcoal rot disease. INTRODUCTION oybeans (Glycine max L.) are susceptible to a large number of pathogens and are most damaged by Macrophomina phaseolina (Tassi) Goid, which targets seedlings and roots (Jana et al., 2003). Charcoal rot is the most important fungal disease of soil borne in soybean. Fungi Macrophomina phaseolina (Tassi) Goid are the cause of charcoal rot among soil borne pathogens which is one of the most important pathogens of various plants in warm regions. Biological control of useful organisms or their products included resulting in reducing the negative effects of the plant pathogens (Vinale et al., 2008). Because fungus is soil borne and has high power of saprophytic, it is not possible to easily control and fungicides cannot control it properly (Mengistu et al., 2011). So researchers have been using biological control and have brought positive results (Gajera et al., 2012; Gupta et al., 2012). Density and survival of T. harzianum on several substrates showed that the use of these formulations significantly reduces wilting in beans and crown rot in peanuts (Singh et al., 2007). Haggag (2002) stated that mutants compared to wild type have higher levels of proline and hydroxyproline, sodium and phenolic compounds and also found that the mutants produced active metabolites such as chitinases, cellulases, β-galactosidase, as well as a number of antibiotics such as trichodermin, Gliotoxin, and gliovirins, which mainly reduced the incidence of the disease. This study was performed to evaluate the efficacy of several mutagenic Trichoderma formulations with gamma ray in the biological control of Macrophomina phaseolina (Tassi) Goid in soybean. S