Diversity of arbuscular mycorrhizal fungi in soils of yam (Dioscoreaspp.) cropping systems in four agroecologies of Nigeria

2013 ◽  
Vol 59 (4) ◽  
pp. 521-531 ◽  
Author(s):  
Michael Olajire Dare ◽  
Robert Abaidoo ◽  
Olajire Fagbola ◽  
Robert Asiedu
2014 ◽  
Vol 48 (3) ◽  
pp. 279-290 ◽  
Author(s):  
Tomoko KOJIMA ◽  
Norikuni OKA ◽  
Toshihiko KARASAWA ◽  
Keiki OKAZAKI ◽  
Shotaro ANDO ◽  
...  

2005 ◽  
Vol 85 (1) ◽  
pp. 31-40 ◽  
Author(s):  
C. Plenchette ◽  
C. Clermont-Dauphin ◽  
J. M. Meynard ◽  
J. A. Fortin

Market globalization, demographic pressure, and environmental degradation have led us to reconsider many of our current agricultural systems. The heavy use of chemical inputs, including fertilizers and pesticides, has resulted in pollution, decreased biodiversity in intensively-farmed regions, degradation of fragile agro-ecosystems, and prohibitive costs for many farmers. Low input sustainable cropping systems should replace conventional agriculture, but this requires a more comprehensive understanding of the biological interactions within agro-ecosystems. Mycorrhizal fungi appear to be the most important telluric organisms to consider. Mycorrhizae, which result from a symbiosis between these fungi and plant roots, are directly involved in plant mineral nutrition, the control of plant pathogens, and drought tolerance. Most horticultural and crop plants are symbiotic with arbuscular mycorrhizal fungi. Mycorrhizal literature is abundant, showing that stimulation of plant growth can be mainly attributed to improved phosphorous nutrition. Although the mycorrhizal potential of its symbiosis to improve crop production is widely recognized, it is not implemented in agricultural systems. There is an urgent need to improve and widely apply analytical methods to evaluate characteristics such as, relative field mycorrhizal dependency, soil mycorrhizal infectivity, and mycorrhizal receptivity of soil. Decreased use of fertilizers, pesticides, and tillage will favour arbuscular mycorrhizal fungi. However, shifting from one system to a more sustainable one is not easy since all components of the cropping system are closely linked. Different cases, from actual agricultural practices in different countries, are analyzed to highlight situations in which mycorrhizae might or might not play a role in developing more sustainable agriculture. Key words: Cropping systems, mycorrhizae, sustainability, technical itineraries, rotation


1999 ◽  
Vol 8 (3) ◽  
pp. 309-318 ◽  
Author(s):  
M. VESTBERG ◽  
M. CARDOSO ◽  
A. MÅRTENSSON

The occurrence of arbuscule-forming fungi in different cropping systems was investigated at Cochabamba in the province of Cercado, Bolivia. The cropping systems included grain and mixed pasture systems, with or without fertilization and agrochemicals. Geographically, the soils studied were situated at 17°23'9'' southern latitude and 66°9'35'' western longitude and a mean height of 2600 m above sea level. Spores of four arbuscular mycorrhiza fungi-forming genera were observed; Glomus Tul. & Tul., Entrophospora Ames & Schneider, Sclerocystis Berk. & Broome emend. Almeida & Schenck and Scutellospora Walker & Sanders. Glomus was the dominating genus, followed by Sclerocystis; Scutellospora and Entrophospora were observed occasionally. A cropping system consisting of a native pasture without any fertilization or other plant or soil treatments had the highest numbers of spores and the highest species richness, i.e. eight out of nine species identified. The mycorrhizal diversity measured with the Shannon-Wiener index did however not differ very much between cropping systems. ;


2005 ◽  
Vol 20 (3) ◽  
pp. 181-189 ◽  
Author(s):  
C. Vatovec ◽  
N. Jordan ◽  
S. Huerd

AbstractArbuscular mycorrhizal fungi (AMF) are plant root symbionts that provide many benefits to crop production and agro-ecosystem function; therefore, management of AMF is increasingly seen as important to ecological farming. Agronomic weeds that form a symbiotic relationship with AMF can increase diversity and abundance of agronomically beneficial AMF taxa. Also, AMF can strongly affect plant community composition, and may thus provide some degree of biological control for weeds. Therefore, relationships between weeds and AMF have a dual significance in ecological farming, but are relatively unexamined. In glasshouse experiments, seedlings of 14 agronomic weed species were grown in the presence or absence of AMF inocula sampled from each of three types of cropping systems: organic, transitional-organic or high-input/conventional. For each weed species, AMF root colonization rates and growth responses to AMF were assessed. On the basis of observed colonization levels, the species were classified as strong hosts (five species), weak hosts (three) and non-host species (six). Among species, biomass responses to AMF were highly variable. Strong hosts showed more positive responses to AMF than weak hosts, although the range of responses was great. Non-hosts did not suffer consistent negative biomass responses to AMF, although strong biomass reductions were noted for certain species–inoculum combinations. Biomass responses to inocula from different cropping systems varied significantly among weed species in one of two experiments. Results suggest that weed–AMF interactions can affect weed community dynamics. We recommend investigation of these interactions in agro-ecosystems that use management methods likely to intensify weed–AMF interactions, such as conservation tillage and cover cropping.


2016 ◽  
Vol 62 (12) ◽  
pp. 1034-1040 ◽  
Author(s):  
M.S. Salloum ◽  
M.C. Guzzo ◽  
M.S. Velazquez ◽  
M.B. Sagadin ◽  
C.M. Luna

Breeding selection of germplasm under fertilized conditions may reduce the frequency of genes that promote mycorrhizal associations. This study was developed to compare variability in mycorrhizal colonization and its effect on mycorrhizal dependency (MD) in improved soybean genotypes (I-1 and I-2) with differential tolerance to drought stress, and in unimproved soybean genotypes (UI-3 and UI-4). As inoculum, a mixed native arbuscular mycorrhizal fungi (AMF) was isolated from soybean roots, showing spores mostly of the species Funneliformis mosseae. At 20 days, unimproved genotypes followed by I-2, showed an increase in arbuscule formation, but not in I-1. At 40 days, mycorrhizal plants showed an increase in nodulation, this effect being more evident in unimproved genotypes. Mycorrhizal dependency, evaluated as growth and biochemical parameters from oxidative stress was increased in unimproved and I-2 since 20 days, whereas in I-1, MD increased at 40 days. We cannot distinguish significant differences in AMF colonization and MD between unimproved and I-2. However, variability among improved genotypes was observed. Our results suggest that selection for improved soybean genotypes with good and rapid AMF colonization, particularly high arbuscule/hyphae ratio could be a useful strategy for the development of genotypes that optimize AMF contribution to cropping systems.


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