Title of Thesis

Integrated use of rhizobacteria containing ACC-deaminase activity, mineral fertilizers and compost to improve growth and yield of oil seed crops

Author(s)

Muhammad Saleem Arif

Abstract
Favorable alliance between rhizosphere bacteria and crop plants induced marked improvement in the plant growth. These beneficial microbes had directly and indirectly shaped plant growth through variety of growth promoting traits. Besides other characteristics, some rhizobacteria have distinguished ability to possess an enzyme 1-aminocyclopropane-1-carboxylate deaminase (ACCD), an immediate precursor of ethylene. Bacterial ACC-deaminase activity modulates endogenous production of ethylene in the rhizosphere thus endorse plant growth promotion. Hence, Use of beneficial bacterial inoculation was assessed through compost and varying level of mineral fertilization in order to improve growth, yield and quality attributes of oil seed crops under study. Organic amendment like compost not only provides an ideal tool for integrated nutrient management with PGPR but also represents a perfect substrate for microbial growth of diverse nature. Integrated effect of rhizobacterial inoculation with organic and inorganic amendments on sunflower and soybean was examined in a variety of experiments. Minimal salt medium with ACC as an ace source of nitrogen had been employed to isolate beneficial bacteria from rhizosphere of both oil seed crops. For authentification, these isolates were further monitored for their diverse plant growth promoting abilities under gnotobiotic conditions. Selected rhizobacterial isolates were further screened under pot experiment in addition to evaluate general growth pattern under pot experiments. Finally, based on performance under pot conditions rhizobacteria were chosen for field trials in two seasons (spring and winter) grown sunflower and soybean respectively. Characterization of selected rhizobacterial isolates was also carried out for several plant growth enhancing attributes. It had been viewed that ACC-deaminase based bacterial biotechnology improved growth, yield and qualitative features of sunflower and soybean through integrated management approach rather than sole inoculation and mineral fertilization.

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2.1 Oil seed crops
2.2 Ethylene and Plant Growth
2.3 Plant Growth Promoting Rhizobacteria
2.4 PGPR- growth promotion mechanisms
2.5 Composting
2.6 Integrated nutrients resource use strategies

3.1 Isolation of rhizobacteria containing ACC-deaminase
3.2 ACC-metabolism Assay
3.3 Preparation of inoculum
3.4 Screening rhizobacteria for their abilities to enhance growth in oil seed crops
3.5 Characterization of rhizobacteria for ACC-deaminase activity
3.6 Characterization of rhizobacteria for other growth promoting traits
3.7 Composting
3.8 Pot experiments
3.9 Field experiments
3.10 Soil analysis
3.11 Plant analysis
3.12 Quality parameters
3.13 Statistical analysis

4.1 Screening of rhizobacteria under gnotobiotic conditions
4.2 Effect of rhizobacteria on growth of sunflower seedlings under axenic conditions (Jar experiment)
4.3 Effect of rhizobacteria on growth of soybean seedlings under axenic conditions (Jar experiment)
4.4 Integrated effect of rhizobacterial inoculation, compost and mineral fertilizers on growth, yield and quality of sunflower under natural conditions.
4.5 Integrated effect of rhizobacterial inoculation, compost and mineral fertilizer on growth, yield and quality of soybean under natural conditions
4.6 Integrated effect of rhizobacterial inoculation, compost and mineral fertilizers on growth, yield and quality of oil seed crops under natural conditions
4.7 Integrated effect of rhizobacterial inoculation, compost and mineral fertilizer on growth, yield and quality of oil seed crops under natural conditions
4.8 Identification and characterization of selected rhizobacteria

5.1 Isolation and screening of rhizobacteria containing ACC-deaminase activity under control condition
5.2 Screening and general plant growth outlook through rhizobacteria containing ACC-deaminase activity integrated with compost and mineral fertilizers of oil seed crops under pot conditions
5.3 Integrated effect of rhizobacteria containing ACC deaminase activity, compost and mineral fertilizers on oil seed crops under field conditions