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Selection of superior genotypes of cashew (Anacardiun occidentale l.
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Subject: Selection of superior genotypes of cashew (Anacardiun occidentale l.
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From: biotec@goliat.ugr.es
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Date: 26 Nov 1996 12:32:06 GMT
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Article: 16744 of alt.sustainable.agriculture
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Newsgroups: alt.sustainable.agriculture
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Organization: Centro Informatico Cientifico de Andalucia
Selection of superior genotypes of cashew in Guinea-Bissau
A project entitled "Selection of superior genotypes of cashew
(Anacardiun occidentale l.) in Guinea-Bissau and development of in
vitro techniques for their propagation", lead by Dr. Raul Sardinha
and Ana Bessa of the Institute de Investigação Científica Tropical,
Portugal in partnership with other scientific institutions in
United Kingdom, Portugal and Guinea-Bissau, was carried out under
the European Union (D.G.XII) STD2 scientific programme.
The cashew is now the main export cash crop for Guinea-Bissau (GB),
reaching an annual value of about 30 000 ton (1992). The commercial
value of the nuts is a quality related characteristic: size,
configuration, density and sanitarian status that may taint
characteristic taste. In GB the tree is currently being extensively
planted by seed without proper selection of propagation material.
Being a free pollinated species and in the absence of seed orchards
or clonal plantations for seed production there is no guaranty on
the value of future crops. This prompted the project aims which
were developed according to three main areas: screening and
selecting cashew trees for their technological characteristics;
study in vitro techniques for clonal tree propagation; and setting
up a clonal tree bank in GB for further breeding and propagation
work.
Tree screening along the characteristics of cashew apple allowed
grouping of trees in seven strata with different cash crop value
(Table 1).
Table 1 - Tree's grouping identification
Tree's Pseudo-fruit Size
Type of
grouping Form Color Size Astringency Consistency
of the nut Branching
A Cordiform ("cajú da terra") Red Medium Low to
medium Low Medium Predom. Intensive to Intensive
B Periform (caju de Moçambique) Predom.Red Medium
High High Big Mixed
C Cordiform Yellow Big Low Medium
toHigh Predom. Extensive to Extensive
D Cordiform Predom.Yellow Small Low to Medium Low
Small Mixed
E Periform Red Medium to Big
Medium to Big Mixed
F Periform Yellow Big High High Big
Extensive
G Cordiform Predom.Red Medium to Big High to
Medium Medium to Big Mixed
(Predom. = Predominantement)
Considering that under the current market system farmers are paid
according nut's weight it is shown that attention to seed quality
and potential is very rewarding. Variation betewen the average
lighter nut group (4.0 g) and the heaviest (8.7 g) ammounted to 4.7
g.
Contract number TS2-A-167
Since yield potential and adaptability to sites prone to "hamatan"
winds are critical phenological studies were carried out. They
showed that flower boson, peak flowering and precociness are
different for almost all groups which reflects their different
ecological adaptability and crop potential that must be considered
in plantation development strategies.
In this project Dr. Sardinha and collaborators have shown the
potential of in vitro propagation methods. They have analyzed the
best explant material to be used. For node culture better media
combination and parameters for shoot production and root
differentiation were studied. Although cashew is considered a
difficult transferring plant, weaning results reached about 83%.
Considering high running cost of tissue-culture laboratories in
tropical countries, the project team showed the potential use of
cuttings under fog conditions (56.8% success). By its simplicity
and relative low costs of the infra-structures needed, results are
clearly promising.
Overall, data so far produced created the basis for a breeding
programme of cashew in GB and open the perspective for quick
multiplication procedures for selected plant cashew production to
improve crop yield of guinean and tropical farmers as well.
Within this project several publications have been issued.
For further information please contact
Raul Sardinha
Rua da Junqueira, 86
1300 Lisboa Portugal
Tel +351 1 364 50 71
Fax: + 351 1 364 20 08
Fax: + 351 1 3973163
Email rosefn@individual.puug.pt, or
Ana Bessa
Fax: +351 1 4423023.
Contract number TS2-A-167