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Effect of
mycorrhizal inoculum and urea fertilizer on diseases
development and yield of groundnut crops (Arachis
hypogaea L.)
Ambang Zachée*, Ndongo
Bekolo, Bime, Ngoh Dooh, Maho Yalen and Ntsomboh Godswill
Department of plant Biology, Faculty of Science, University
of Yaoundé I, P.O. Box 812 Yaoundé, Cameroon.
*Corresponding author. E-mail:
zachambang@yahoo.fr.
Tel: (237) 9 935-41-56.
Accepted
11 July, 2008 |
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Diseases
(rosette virus disease (RVD), Cercospora leaf spot (CLS)
and poverty of soils in nutrients are the main causes of
groundnut losses (>60%). Among the methods applied in
disease management, the biological method is identified as a
priority in crop protection research programs.
This study was carried out during the 2001 growing season in
Yaoundé, Cameroon. The aim was to characterize the
development of RVD and CLS on A-26 groundnut variety and
also to evaluate yield after mycorrhizal inoculation. A
randomized block design with four replicates was used, with
two applications of mycorrhizal inoculum. The inoculum
contained spores of Glomus sp. and
Gigaspora sp. in concentration of 2.103
spores.g-¹. A urea treatment and an absolute
control were also used. The number of nodules per plant, the
root colonization rate (RCR), disease severity and yield
were assessed. Results show that RCR was very low in control
and urea plots compared to mycorrhizal inoculated plots.
Mycorrhizal applications reduced disease infection up to
38.8 and 54.4% respectively, for RVD and CLS. However,
plants issued from urea treatment were more stressed and
infected. A higher number of nodules (459.1) were recorded
on roots of mycorrhizal inoculated plants compared to
control and urea treatments which were 218.8 and 237.5
nodules per plant. Mycorrhization of groundnut plants led to
a yield increased of up to 628% for dry pods of healthy
plants compared to uninoculated plants in control samples.
No yield was recorded on infected plants from control and
urea treatments, whereas plants infected by RVD and
inoculated with mycorrhiza yielded 177.2 Kg.ha-1
of dry pods. The mains results of this study show that
mycorrhizal symbiosis with groundnut roots increased the
resistance of plants to RVD and CLS, and positively
influenced the physiology of groundnut plants infected by
RVD.
Key
words:
Arachis hypogaea, mycorrhization, disease
development, biological control, yield increase. |
