2022

Bacterial community of water yam (Dioscorea alata L.) cv. A-19

The bacterial community of water yam (Dioscorea alata L.) cv. A-19 is vital because it may promote plant growth without the need for fertilization. However, the influence of fertilization practices on the composition and proportion of the bacterial community of water yam cv. A-19 has not yet been extensively examined. Therefore, we herein investigated the diversity and composition of the bacterial community of water yam cv. A-19 cultivated with and without chemical fertilization using amplicon community profiling based on 16S rRNA gene sequences... 

2021

Growth of water yam (Dioscorea alata L.) as affected by bacterial inoculation under growth chamber conditions

Soil fertility is one of the most important limitations in yam (Dioscorea spp.) growth and yield. This study evaluated the effect of bacterial inoculation on the growth and source of nitrogen in water yam (D. alata L.) cv. A-19 under growth chamber conditions. The plants were inoculated with two different inoculant concentrations (10+4 and 10+6 CFU. ml-1) of Agrobacterium sp. strain 343, which was previously isolated from the root of water yam cv. A-19...

2020

Rhizobium dioscoreae sp. nov., a plant growth-promoting bacterium isolated from yam (Dioscorea species)

This study investigated endophytic nitrogen-fixing bacteria isolated from two species of yam (water yam, Dioscorea alata L.; lesser yam, Dioscorea esculenta L.) grown in nutrient-poor alkaline soil conditions on Miyako Island, Okinawa, Japan. Two bacterial strains of the genus Rhizobium, S-93 T and S-62, were isolated. The phylogenetic tree...

Response of Upland Rice (Oryza sativa L.) Inoculated with Non-Native Plant Growth-Promoting Bacteria

A deep-rooting upland rice variety (Kinandang Patong) was evaluated for its growth response to bio-fertilization at early stages. Five non-native plant growth-promoting bacteria previously isolated from yams (Dioscorea spp.) were inoculated to upland rice under growth chamber and greenhouse conditions. Effects of the inoculation varied...

Infection route of endophytic nitrogen-fixing bacteria in water yam (Dioscorea alata L.)

In our previous experiment, water yam (Dioscorea alata L.) was able to grow under low-fertility soil conditions and nitrogen in the plant was found to be derived from the air. Moreover, some genera of nitrogen-fixing bacteria (NFB) were subsequently isolated. The objective of this study, therefore, was to confirm and identify the infection route of NFB in water yam plants...

2019

(Ph.D. thesis) Studies on Nitrogen-Fixing Bacteria Associated with Yams (Dioscorea spp.).

Nitrogen (N) is of great importance in agricultural activities as it is required in larger amount compared to other nutrients and is involved in vital biological processes. Inappropriate use of N fertilizers results in environmental problems (eg, eutrophication of soils and waters, climate change). Industrial production of N fertilizers is not sustainable...

Nitrogen-Fixing Bacteria Associated with Yams (Dioscorea spp.) Growth

Yams (Dioscorea spp.) have been cultivated with traditional method but intensive farming as the cash crop has been increasing in West Africa. The effect of fertilizer in yam growth varied on cultivation method and species and fertilization management. The fertilization method in yams is not established in tropical area (Shiwachi et al., 2015). The results of experiments were suggested water yam (D. alata) able to grow under poor fertile soil...

Endophytic nitrogen-fixing bacteria of water yam (Dioscorea alata L.) in relation with fertilization practices

Plant internal environment harbors several microorganisms that exhibit beneficial effects to the growth, adaptability and productivity of their host plants. Diazotrophs are bacteria responsible for biological nitrogen fixation (BNF) in plants. Yam (Dioscorea spp.) is an important tuber crop for food security in West Africa, but also is the most neglected crop in term of research. This experiment evaluated endophytic nitrogen-fixing bacteria associated with water yam (D. alata) grown under different fertilizer regimes and the...

Isolation and identification of nitrogen-fixing bacteria associated with Dioscorea alata L. and Dioscorea esculenta L.

Yams are important tuber crops in the tropics. Nitrogen is one of the limiting factors in yam production. Yam accessions that can rely on biological nitrogen fixation must be identified if we are to achieve efficient and sustainable yam production. The aim of this study was to isolate and identify the endophytic diazotrophic bacteria of 19 accessions of two yam species. Forty-one endophytic bacteria were isolated from surface-sterilized roots, stems and leaves of yam accessions grown in nutrient-poor subsoil for 160 days...

Contribution of biological nitrogen fixation in lesser yam (Dioscorea esculenta L.) associated with endophytic diazotrophic bacteria

Three accessions of lesser yam (Dioscorea esculenta L.) were grown under different fertilizer regimes in pots for 220 days at Miyako Island, Okinawa, Japan. Biological nitrogen fixation (BNF) was evaluated in non-fertilized plants. Nitrogen-fixing endophytic bacteria were isolated on nitrogen-free Modified Rennie medium at 180 days after planting (DAP). Results show that growth of lesser yam was affected by fertilizer regimes. Plant nitrogen content was increased under chemical fertilizer and organic...