Informations et ressources scientifiques
sur le développement des zones arides et semi-arides

Titre : Selection and Diversity Analysis of Plant Growth Promoting Rhizobacteria from the Cold Desert of Lahaul and Spiti

Auteur : Vyas, Pratibha

Université de soutenance : Guru Nanak Dev University

Grade : Doctor of Philosophy (PhD) 2010

Sommaire partiel
Plant growth-promoting rhizobacteria present an alternative to the use of chemical fertilizers and pesticides in enhancing crop productivity. The use of PGPR has attracted wide-reaching attention as microbial inoculants for increasing agricultural productivity. Fluorescent Pseudomonas often predominate among the plant rhizosphere bacteria and influence plant growth by several mechanisms. However, the establishment and performance of these microorganisms are severely affected by the stress generated by the environmental factors like moisture status, temperature, alkalinity/acidity and salinity in the soil. The beneficial effects of PGPR have been demonstrated in many crops. However, inconsistency in their field performance attributed mainly to poor rhizosphere competence and lack of multiple plant growth-promoting activities is the major limiting factor in realizing the full potential offered by these microorganisms. The successful outcome of the application of microbial inoculants largely depends on the selection of efficient, stresstolerant and rhizosphere-competent strains. Exploring the stressful niches is important for the selection of PGPR with stress tolerance ability. The cold desert of Lahaul and Spiti located in the Indian trans-Himalayas is marked by a stressful milieu with poor availability of some essential mineral nutrients in the soil. The immense potential of stress-tolerant microorganisms for improving crop productivity remains unexplored and untapped from the cold deserts. The identification, characterization and assessment of genetic diversity of beneficial microorganisms are important to developing deployment strategies for increasing their contribution in agriculture. PGPR revealing huge potential for enhancing crop production must also be mass-produced and formulated into a cost-effective, uniform and readily applicable form for commercial application. Accordingly, the present studies were undertaken on selection of efficient strains with multiple plant growth-promoting attributes, stress tolerance, rhizosphere competence, and optimization and scaling-up inoculum production for application as microbial inoculants for improving crop productivity.

Mots clés : Plant Growth Cold Desert of Lahaul

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