Compatibility of Trichoderma Harzianum and Pseudomans Fluorescens With Agro-chemicals in Wheat Rhizosphere

Abstract

Wheat (Triticum aestivum L.) the world’s most important food crop, serve as the prime item in the diet of millions of people. Wheat is an important crop in terms of production and consumption both. Production of wheat in India is limited by several biotic and abiotic stresses. In present situation of climate changes, all crops including wheat are facing extreme water deficit, which adversely affects crop growth and yield. Present studies have been focused to investigate the effect of antagonist fungus and bacteria viz Trichoderma harzianum and Pseudomonas fluorescens for the management of drought stress in wheat. Out of several strains of T. harzianum and P. fluorescens collected from different locations of Uttar Pradesh and from various crop’s rhizosphere, most superior and capable eleven strains on the basis of their growth rate were selected. These selected strains were applied as seed bio-priming to test their efficacy to enhance drought tolerance in wheat at stem elongation/jointing stage. Some selected strains of T. harzianum and P. fluorescens viz. IRRI-1, PfBN-6, PfBP-2 and TH-3 supported very high growth of root and shoot along with enhancement in root and shoot biomass in wheat plants. After five, eight, eleven and fourteen days of exposure to drought IRRI-1, PfBN-6, PfBP-2 and TH-3 strains of T. harzianum and P. fluorescens showed maximum leaf area and flag leaf area. These most effective strains i.e. IRRI-1, PfBN-6, PfBP-2 and TH-3 were also able to enhance the drought tolerance in wheat crop by decreasing the proline content and by enhancing the total chlorophyll content, relative water content, membrane stability index and by increasing biochemical properties i.e. catalase and peroxidase activity in wheat plants. Thus, IRRI-1, PfBN-6, PfBP-2 and TH-3 strains of T. harzianum and P. fluorescens have been found to be effective in providing drought tolerance in wheat plants by interfering in the morpho- physiological and biochemical activities of wheat plants. Among the fungicides, Nativo and Propiconazole were found to be most compatible against T. harzianum (IRRI-1) and P. fluorescens (PfBN-6). Among four insecticides i.e. Chloropyriphos and Thiamethoxam were found to be comparatively less toxic and compatible with T. harzianum (IRRI-1). In case of P. fluorescens (PfBN-6) Chloropyriphos and Imidacloprid were found to be most compatible. Among four weedicides Pendimethalin and 2, 4-D was found to be most compatible with T. harzianum (IRRI-1) and P. fluorescens (PfBN-6). In field experiment Nativo and Tebuconazole were most effective for increasing chlorophyll content, shoot fresh weight, shoot length, root length, flag leaf area, leaf area and yield of wheat crop.