Document Type : Research Article
Department of Plant Protection, Faculty of Agriculture, University of Birjand, Birjand, Iran
Associate Professor, Department of Plant Protection, Birjand University
Assistant Professor of Agriculture Department, Birjand University
Associate Professor, Department of Agriculture, Birjand University
Introduction: Trichoderma species are the main causes of decomposition and decay of agricultural residues and are considered for the control of plant pathogens, especially fungi and nematodes in the world. Trichoderma species have the ability to produce microbial enzymes such as xylanases, which are used in the paper and food processing industries. These enzymes improve the digestibility of nutrients in certain diets in ruminants and poultry, where there is no digestive enzyme that can digest the complex carbohydrates in the cell wall. These enzymes have the power to digest and hydrolyze these substances. South khorasan province due to hot and dry climate, water shortage and successive droughts, saline water in agriculture, pests and diseases, soil with low fertility for planting irrigated wheat needs cultivars resistant to these stresses. Narin cultivar is the latest cultivar introduced for this province. The characteristic of this cultivar are more compatibility with salinity stress areas and relative maturity with other wheat cultivars.
Materials and Methods: In order to investigate the effect of simultaneous use of Trichoderma harzianum and plant mulch on yield and physiological characteristics of wheat of Narin cultivar and its effect on the interaction of this cultivar with Alternaria alternata in 2019-2020 in Birjand Faculty of Agriculture Research Farm an experiment asComplete randomization block design was performed with four replications. Treatments included control (without application of Trichoderma), Trichoderma as soil application, Trichoderma as leaf application in granulation stage, Trichoderma application as soil and leaf application in granulation stage. In the granulation stage, each experimental unit was divided into two parts and Alternaria leaf spot pathogen treatment at two levels (inoculation in the granulation stage and without inoculation) was considered as a sub-factor in the experiment. The purpose of using the pathogen treatment was to evaluate the effect of Trichoderma in the presence of the pathogen. This fungus was prepared from the archives of the Plant Pathology Laboratory of Birjand University of Agriculture, which had previously been isolated from the wheat of this province. To inoculate this pathogen, a suspension with a concentration of 106 spores per ml of A. alternata was used from a 7-day fungus colony on PDA medium and its effect on physiological traits (including total phenol, chlorophyll a, chlorophyll b, carotenoids, total chlorophyll) were investigated. To investigate the effect of different applications of Trichoderma on Narin cultivar from another part of the plot without pathogen treatment was analysis of growth traits, yield and yield components including chlorophyll index, including green and dry stem height, spike length, weight, grain yield, biological yield, number and weight of grains per spike, spikes number and weight per unit area were measured.
Results and Discussion: The aim of using pathogen treatment was to evaluate the biological control of Alternaria wheat leaf spot agent by T. harzianum in different methods by using Trichoderma in the presence of Alternaria in comparison with the absence of Alternaria and its effect on physiological traits (including total phenol, chlorophyll a, Chlorophyll b, carotenoids, total chlorophyll) were evaluated. No symptoms of necrosis or leaf chlorosis were observed after pathogen inoculation. Analysis of physiological traits (total phenol, chlorophyll a, chlorophyll b, carotenoids, total chlorophyll) showed that only the simple effect of inoculation or non-inoculation of Alternaria with Trichoderma significantly different (P <0.05) in terms of total phenol content. Due to the presence of Alternaria as a pathogen, it may lead to a reaction of the plant's defense system, and Trichoderma can also increase phenolic compounds to counteract the pathogen. Analysis of growth traits, yield and yield components showed that Trichoderma treatment had no significant effect on any of them.
Conclusion: This study, for the first time showed that A. alternata can cause disease on wheat Narin cultivar. Also, this research studied the effect of T. harzianum on physiological and functional characteristics of wheat Narin cultivar and results demonstrated that T. harzianum can have little effect on these characteristics of Narin cultivar. Concomitant use of Trichoderma in soil and leaves had a greater effect than separate application in roots or leaves. Also, according to other research, the effect of trichoderma varies depending on the environmental conditions including temperature and humidity, soil texture and structure and the type of wheat cultivar.
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