Download Introduction: Irvingia gabonensis

Control of Fungi Isolated From IrvingiaGabonensis in Eke Awka Market
With Plant Extracts of Chromolaena odorata.
PH.D RESEARCH PROPOSAL.
By
OKONKWO-CHUEMEKA, CHIDINMA .J.
Introduction: Irvingia gabonensis(Aubry- Leconte ex O’Rorke) is a species of
African trees in the genus Irvingia, sometimes known by the common names wild
mango, African bush mango, dika or ogbono. They bear edible mango-like fruits,
and are especially valued for fat and protein rich nuts. Irvingia is a nutritional
important non-timber wood plant with edible parts such as fruits, nut and Kernel
(Ladipo, 1996)
I.gabonensis are socio-economically important food crop which range from their
use as food, medicine and environmental control such as planting alongside other
species to check soil erosion (Agbor, 1994)
Irvingia gabonensis occurs in the wild in lowland forest; 2-3 trees occur together
and in some areas it is reported to be gregarious. The dika nut tree is specie of
moist forest.
It grows at from 200-500m with annual rains from 1,500-3,000mm. Supported
temperatures range from 20 degrees Celsius to 38 degrees Celsius under slightly
shaded to very bright, clear skies. Deep soils with more than 150cm are requested
with a moderate fertility and good drainage. The pH can vary from 4.5 to 7.5.
It is native to Angola, Cameroon, Central African Republic, Congo, Equitorial
Guinea, Gabon, Ghana, Guinea-Bissau, Liberia, Nigeria, Senegal, Sierra Leone,
Sudan, Uganda ( Orwa et al.,2009).
Irvingia gabonensis grows straight, up to a height of 40m and 1m in
diameter(Orwa et al., 2009).
It has buttresseses till a height of 3metres. The outer bark is smooth to scaly with
grey to yellow grey colour and brittle. The crown is evergreen, spherical and
dense. Leaves 5-15 by 2.5-6cm are elliptic, one margin is often a little rounder than
the other, acuminate, acute or shortly slightly rounded at the base, dark green and
glossy on the upside with 5-10 pairs of irregular leteral veins,the lower ones
running out nearly to the margin (Keay, 1989).
The flowers are bisexual. Flowers are yellow to greenish-white, in slender small
panicles above the leaves and about as long as them, or on the bracelets and
younger branchlets; individual flower stalks slender, about 6mm long.
Fruits yellowish when ripe, broadly ellipsoild and variable in sieze between
varieties, 5-7cm with a yellow, fibrous pulp surrounding a large seed ( Ladipo et
al., 1996).
NUTRITIONAL VALUE OF IRVINGIA GABONENSIS
Nutritive Value of the Kernels per 100g edible portion, which corresponds to about
2918kj of energy.
Fat
67g
Carbohydrate
15g
Protein
8.5g
Water
4g
Calcium
120g
Iron
2.4mg
Kernels of Irvingia gabonensis contain traces of thiamine 0.22mg, riboflavin
0.08mg, niacin 0.5mg (platt, 1962). The appropriate fatty acid composition is
myristic acid 33-70% laureic acid 20-59%, oleic acid 1-11% plamitic acid 1%
(Leakey et al., 2000).
The contained amino acids are reasonably balanced for human nutrition. Since
lysine, tryptophan, Valine, threonine, isoleucine and phenylalanine have high
concentrations in the seed. Methionine and Cysteine are also present.
USES OF IRVINGIA
1.
2.
3.
4.
5.
For food
For Industrial
Medicine
Environment
Traditional
There are many micro organisms associated with Irvingia gabonensis seed in
Nigeria which may includes: Aspergillus niger, Aspergillus funmigates, Rhizopus
nigericans which are the major cause of seed deterioration (Chuku et al., 2008).
The use of chemicals to control pathogen has helped increase the yield obtained.
Such chemicals include carboxamide fungicide (7.4), captain thiran (7.3)
(Kolchaar, 2006).
Some of these pathogens can also be treated by immersing in hot water at 52
degrees Celsius for fifteen minutes but the disadvantage is the need to dry the seed
rapidly after treatment (Kolchaar, 2006).
Biological method of control has been preferred in most cases because it is
affordable, durable and free of chemicals that can pollute environment. The
persistence to biological control is rare and biological agents are self propagating
and self perpetuating ( Okigbo, 2002). Biological control is generally favoured as a
method of plant disease management (Okigbo and Ikediugwu, 2000; Okigbo,
2002: 2005). Plants extract have been used to control I.gabonensis Chromolaena
odorata seed diseases.
Therefore, in this report the antifungi properties of (L.) King and Robinson and
Mitracarpus villosus (Swartz)de Candolle against some spoilage fungi responsible
for Irvingia gabonensis seed spoilage were reported.
Chromolaena odorata (L.) R.M King and H. Robinson is in the plant family
Asteraceae generally known as siam weed. It is a fast- growing perennial herb and
native to South and Central America (Ambika and Jayachandra, 1980). It has been
introduced into the tropical region of Asia, Africa.
In the Southern part of Nigeria, the leaves are used for wound dressing, skin
infection and to stop bleeding. The medicinal values of plants lie in the component
phytochemicals such as alkaloid, tannin, flavonoid, saponin and phenol which
produce a definite physiological action on human body (Hill, 1992).
The objectives of this study;
i.
ii.
iii.
To identify the fungi present in Irvingia gabonensis.
To investigate the efficacy of using two local plants in controlling the
fungi
To find out the best extraction media.
MATERIALS AND METHODS
a.
b.
c.
d.
Collection of plant materials
Preparation of Sabourand Dextrose Agar (SDA)
Isolation of fungi from seeds
Identification of fungi isolates
e.
f.
g.
h.
i.
Pathogenecity test
Drying of plant materials
Preparation of the plant extracts
Invitro effect of plant extracts on pathogen
Statistical Analysis
REFFERENCES
Ambica, S.R and Jayachandra, T. (1980): Supression of plantation crops
by Eupatorium weed.
Curriculum Science. 49:875-894.
Agbor, L.O.N (1994). Marketing trends and potentials for Irvingia
gabonensis products in Nigeria. ICRAF-IITA Conference on Irvingia
gabonensis; Ibadan, Nigeria; 23 May 1994.
Chuku, E.C., Ogbonna, D.N., Onuegbu, B.A., Adeleke, M.T.(2008).
Journal of Applied Science. 8: 168-172.
Hill, A. F. (1992). Economic botany. A test book of useful plants and
product. Second M.C Graw Hill Book Company Inc. New York. 12:5057
Keay, R.W (1989). Trees of Nigeria. Claredon Press Oxford. 117pp.
Kolchaar, K. (2006). Economic botany in tropics. Macmilliam, India
43pp.
Ladipo, D.O, Fondoun, J.M, Gana, N. (1996). Domestication of the bush
mango (Irvingia Spp). Some exploitable intra-specific variation in West
and Central Africa. In:
Domestication and Commercialization of Non-Timber Forest Products for
Agroforestry (eds) Leakey, R.R.B., Temu, A.B., Melnyk, M. and
Vantomme, P.pp 193-206.
Okigbo, R.N (2002). Mycoflora of tuber surface of white yam (Dioscorea
rotundata) and postharvest control of pathogen with Bacillus subtilis.
Mycopatholohia, 156(2): 81-85.
Okigbo, R.N and F.E.O Ikediugwu, (2000). Studies on biological control
of post-harvest rot of yams (Dioseorea spp) with Trichoderma viride.
Journal of Phytopathol., 148: 351-355.
Orwa, C., Mutual, A., Kindt, R., Jammanadass, R., Simons, A.
(2009).Agro forest tree Database: a tree reference and selection guide.
Version 4.0 (http://www.worldagroforestry.org/af/treedb/) (Cited 23rd
june, 2013).