The worldwide increases in both environmental damage and human population pressure have the unfortunate consequence that global food production may soon become insufficient to feed all of the world’s people. It is therefore essential that agricultural productivity be significantly increased within the next few decades. Large amounts of chemical fertilizers are generally used to improve growth and yield of crops. However, increasing costs of these fertilizers and environmental concerns related to their use have led to the development of alternative strategies. Agricultural practice is moving toward a more sustainable and environmentally friendly approach. The use of beneficial soil microorganisms could reduce the amount of fertilizer input by increasing the efficiency of nutrient availability and other plant growth promoting activities. Bio-fertilizers hold a promise to balance many drawbacks of the conventional chemical based technology and could recuperate healthy farming practices and organic farming.
Arbuscular mycorrhizal fungi (AMF) are known to occur widely under various environmental conditions and are found associated with roots of most of the food crops (Chen et al., 2005; Souchieet al., 2006). The AM fungi form a filamentous network in soil and plant roots which promotes bi-directional nutrient movement. Nutrients taken up by the mycorrhizal fungi can lead to improved plant growth and reproduction in infertile soils. As a result, mycorrhizal plants are often more competitive and are able to tolerate environmental stresses compared to non-mycorrhiza plants. The application of AM fungi led to noteworthy enhancements on plant growth, vigour, nutrient and water uptake, disease resistance and drought tolerance (Jeffries etal., 2003; Sanchez-Blanco et al., 2004; Gohre and Paszkowski, 2006; Wu and Xia, 2006). The co-inoculation of AMF with some other microorganisms has been proved in several reports to support plant growth. Plant growth promoting rhizobacteria has been confirmed to support AMF in plant development.
Plant growth promoting rhizobacteria (PGPR), especially phosphate solubilizing bacteria (PSB), which reside in the plant rhizosphere, increase the availability of P for the plants by solubilization of bound P in soil (Igualet al., 2001). Due to limited diffusion and formation of a Pi-depletion zone surrounding the root system, the phosphate made available by PSB from sparingly soluble inorganic P (Pi) sources may not reach the root surface, therefore it was proposed that if the solubilized phosphate was taken up first by AM mycelium, this synergistic microbial interaction should improve P supply to the plant. In particular, AM inoculation improves the establishment of both inoculated and indigenous phosphate-solubilizing rhizobacteria acting as helping bacteria (Barea et al., 2002). It was found that plants inoculated with AM fungi either alone or in combination with PSB, increased the P uptake remarkably in many cash crops such as wheat and maize (Raja et al., 2002).
Maize (Zea mays L.) is a member of the grass family, Poaceae. It is one of the most important cereal crops in the world (Agbogidi, 2010). Maize is the most important cereal crop in Nigeria providing over 40% of the calories consumed in both rural and urban areas. The crop has increasingly become a staple food in many parts of the country due to changes in people eating habits. Small-scale farmers, who constitute the bulk (80%) of the rural people, also account for the largest share of maize producers.
1.1 JUSTIFICATION OF THE STUDY
The study of the synergistic relationship between arbuscular mycorrhiza fungi and plant growth promoting bacteria is expanding rapidly, there are some numbers considering how long has been and long and far it would be of help towards the sustenance of agriculture not only at low level but widespread. This project write up is to view the effectiveness of the co-inoculation of AMF and PGPR (Bacillus chlororance) on maize.
1.2 AIM OF STUDY
- To study the impact of co-inoculation of different species of arbuscular mycorrhiza fungi and plant growth promoting bacterial (Pseudomonas chlororaphis) on maize (Zea mays L.).
1.3 OBJECTIVES OF STUDY
- To investigate the effect of the inoculation of arbuscular mycorrhizal fungi and plant growth promoting bacterial (Pseudomonas chlororaphis)on maize (Zea mays L.).
- To evaluate the effect of selected vesicular arbuscular mycorrhizal spores and Pseudomonas chlororaphis on maize (Zea mays L.).