Growth Improvement of Tomato With the Application of Bacterial Isolates Producing Indole Acetic Acid (Iaa) and Phosphate Solubilizer

Abstract

<p class="keyword">Soil bacteria have important roles in biogeochemical cycle for soil fertility and have been manipulated for ecologically-friendly crop production. The search for beneficial association between microbes and plants for promoting growth and health should be studied for tomato growth improvement. The study aimed to evaluate 19 microbial isolates which produced indole acetic acid (IAA) affecting growth and development of tomato (Palupi variety), and molecularly identify the most effective isolates in improving tomato growth based on 16s rDNA sequences. The experiment was conducted in pots using a complete randomized design with three replications. The parameters observed included plant height, plant dry weight, root length, root dry weight, and fruit fresh weight. The isolates that significantly improved tomato growth were molecularly identified using 16s rRNA sequence. The phenotypic properties such as IAA content and phosphate solubilizing index (PI) of the superior isolates were determined. Results showed that the application of bacterial isolates on tomato significantly increased plant dry weight and fruit yield. From 19 isolates tested, Aj 3.7.1.14 significantly increased plant dry weight, root length, and fruit yield. This isolate produced IAA of about 14.77 ppm and PI of 1.86. Molecular analysis on Aj 3.7.1.14 demonstrated that the isolate had 89% similarity to <em>Pseudomonas fragi</em>. The identified <em>P. fragi</em> was found to be the most effective isolate for improving tomato growth and fruit yield. Another isolate, <em>Bacillus amyloliquefaciens</em> was found to promote root length, root dry weight, and fruit yield. These isolates are potential to be further investigated for field trials</p>

Biopriming of cayenne seed (Capsicum frutescens L.) using Indole Acetic Acid (IAA) - producing fluorescent pseudomonads to increase germination and growth of seeds

“…This is in line with what was stated by Ali et al, [30] that inoculation of IAA-producing bacteria can induce plant growth which has an impact on increasing plant dry weight, root length, number of roots, and root surface area. Riyanti et al, [31] stated that of the 19 isolates tested, Pseudomonas fragi isolates Aj 3.7.1.14 had a moderate concentration of IAA (14.77 ppm), and could increase root length, plant dry weight, and tomato fruit yield.…”