Indole-3 Acetic Acid Producing Rhizobacteria and its Potential to Enhance Growth of Sweetpotato (Ipomoea Batatas L.)

The problem in sweetpotato cultivation is yield reduction with continuous planting, which can be attributed to several factors such as soil degradation, pathogenic effects, and allelopathic effects. One of the approaches to alleviate this problem is by inoculating plants with indole-3-acetic acid...

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Main Author:	Maira, Lusi
Format:	Thesis
Language:	English English
Published:	2000
Subjects:	Indoleacetic acid Rhizobacteria Sweet potatoes - Harvesting
Online Access:	http://psasir.upm.edu.my/id/eprint/10518/1/FP_2000_11.pdf
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id	my-upm-ir.10518
record_format	uketd_dc
spelling	my-upm-ir.105182024-04-03T07:14:16Z Indole-3 Acetic Acid Producing Rhizobacteria and its Potential to Enhance Growth of Sweetpotato (Ipomoea Batatas L.) 2000-12 Maira, Lusi The problem in sweetpotato cultivation is yield reduction with continuous planting, which can be attributed to several factors such as soil degradation, pathogenic effects, and allelopathic effects. One of the approaches to alleviate this problem is by inoculating plants with indole-3-acetic acid (IAA) producing rhizobacteria to enhance growth of sweetpotato. The study consisted of four experiments. Experiment I was the isolation of rhizobacterial strains from sweet potato rhizosphere and their performance in sweetpotato root exudate culture. Experiment II was the selection of IAA producing rhizobacteria and their effects on sweet potato growth. Experiment III was the determination of the effect of pH and carbon sources on growth of rhizobacteria isolated from sweetpotato rhizosphere. Experiment IV was the determination of the effects of L-tryptophan (T RP) on performance of IAA producing rhizobacteria on growth of sweetpotato. From the isolation procedures, 115 rhizobacterial isolates were collected from different varieties of sweetpotato grown on different soils. They were grouped into 6 types according to colour of the colonies which consist of purple, milky white, translucent, orange, yellow and brown. The study showed that 48 isolates (41.74 %) were able to grow on medium containing sweetpotato root exudate of which, 18 isolates (37.5%) were able to produce IAA in culture medium which ranged between 4 to 8 ug/m L. The first pot experiment showed that 6 isolates ( SP R 66, SP R 83, SP R 85, SP R 88, SP R 100 and 90-166) were able to stimulate the initial growth of sweetpotato vines. Three of the isolates namely SP R 66, SP R 83 and SP R 100 showed positive responses on media with wide range of pH and different carbon sources. The optimum pH of medium for rhizobacterial growth was 6.75, and the most favourable carbon source was malic acid. The second pot experiment showed that isolate SP R 66 increased the shoot dry weight, chlorophyll content and total leaf area of shoots, while isolate SP R 100 increased the dry weight and volume of roots, the storage root formation, nutrient concentration in shoots and soil nutrient contents. The addition of L-T RP to all selected rhizobacterial isolates enhanced growth and yield of sweetpotato. It related to the improved of soil chemical properties and microbial activity. Indoleacetic acid Rhizobacteria Sweet potatoes - Harvesting 2000-12 Thesis http://psasir.upm.edu.my/id/eprint/10518/ http://psasir.upm.edu.my/id/eprint/10518/1/FP_2000_11.pdf text en public masters Universiti Putra Malaysia Indoleacetic acid Rhizobacteria Sweet potatoes - Harvesting Faculty of Agriculture Othman, Radziah English
institution	Universiti Putra Malaysia
collection	PSAS Institutional Repository
language	English English
advisor	Othman, Radziah
topic	Indoleacetic acid Rhizobacteria Sweet potatoes - Harvesting
spellingShingle	Indoleacetic acid Rhizobacteria Sweet potatoes - Harvesting Maira, Lusi Indole-3 Acetic Acid Producing Rhizobacteria and its Potential to Enhance Growth of Sweetpotato (Ipomoea Batatas L.)
description	The problem in sweetpotato cultivation is yield reduction with continuous planting, which can be attributed to several factors such as soil degradation, pathogenic effects, and allelopathic effects. One of the approaches to alleviate this problem is by inoculating plants with indole-3-acetic acid (IAA) producing rhizobacteria to enhance growth of sweetpotato. The study consisted of four experiments. Experiment I was the isolation of rhizobacterial strains from sweet potato rhizosphere and their performance in sweetpotato root exudate culture. Experiment II was the selection of IAA producing rhizobacteria and their effects on sweet potato growth. Experiment III was the determination of the effect of pH and carbon sources on growth of rhizobacteria isolated from sweetpotato rhizosphere. Experiment IV was the determination of the effects of L-tryptophan (T RP) on performance of IAA producing rhizobacteria on growth of sweetpotato. From the isolation procedures, 115 rhizobacterial isolates were collected from different varieties of sweetpotato grown on different soils. They were grouped into 6 types according to colour of the colonies which consist of purple, milky white, translucent, orange, yellow and brown. The study showed that 48 isolates (41.74 %) were able to grow on medium containing sweetpotato root exudate of which, 18 isolates (37.5%) were able to produce IAA in culture medium which ranged between 4 to 8 ug/m L. The first pot experiment showed that 6 isolates ( SP R 66, SP R 83, SP R 85, SP R 88, SP R 100 and 90-166) were able to stimulate the initial growth of sweetpotato vines. Three of the isolates namely SP R 66, SP R 83 and SP R 100 showed positive responses on media with wide range of pH and different carbon sources. The optimum pH of medium for rhizobacterial growth was 6.75, and the most favourable carbon source was malic acid. The second pot experiment showed that isolate SP R 66 increased the shoot dry weight, chlorophyll content and total leaf area of shoots, while isolate SP R 100 increased the dry weight and volume of roots, the storage root formation, nutrient concentration in shoots and soil nutrient contents. The addition of L-T RP to all selected rhizobacterial isolates enhanced growth and yield of sweetpotato. It related to the improved of soil chemical properties and microbial activity.
format	Thesis
qualification_level	Master's degree
author	Maira, Lusi
author_facet	Maira, Lusi
author_sort	Maira, Lusi
title	Indole-3 Acetic Acid Producing Rhizobacteria and its Potential to Enhance Growth of Sweetpotato (Ipomoea Batatas L.)
title_short	Indole-3 Acetic Acid Producing Rhizobacteria and its Potential to Enhance Growth of Sweetpotato (Ipomoea Batatas L.)
title_full	Indole-3 Acetic Acid Producing Rhizobacteria and its Potential to Enhance Growth of Sweetpotato (Ipomoea Batatas L.)
title_fullStr	Indole-3 Acetic Acid Producing Rhizobacteria and its Potential to Enhance Growth of Sweetpotato (Ipomoea Batatas L.)
title_full_unstemmed	Indole-3 Acetic Acid Producing Rhizobacteria and its Potential to Enhance Growth of Sweetpotato (Ipomoea Batatas L.)
title_sort	indole-3 acetic acid producing rhizobacteria and its potential to enhance growth of sweetpotato (ipomoea batatas l.)
granting_institution	Universiti Putra Malaysia
granting_department	Faculty of Agriculture
publishDate	2000
url	http://psasir.upm.edu.my/id/eprint/10518/1/FP_2000_11.pdf
_version_	1804888558490615808

Indole-3 Acetic Acid Producing Rhizobacteria and its Potential to Enhance Growth of Sweetpotato (Ipomoea Batatas L.)

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