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Rice breeding for african highlands
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Subject: Rice breeding for african highlands
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From: biotec@goliat.ugr.es
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Date: 26 Nov 1996 12:16:54 GMT
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Article: 16796 of alt.sustainable.agriculture
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Newsgroups: alt.sustainable.agriculture
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Organization: Centro Informatico Cientifico de Andalucia
Rice breeding for african highlands
A project entitled “Study of constraints linked to rice growing at
high altitude and development of adapted varieties” lead by Prof.
J. Bouharmont of Université Catholique de Louvain, Belgium, in
partnership with other scientific institutions in France, Burundi,
Madagascar and Togo, was carried out under the European Union
(D.G.XII) STD2 scientific programme.
Rice cultivation has recently been developed in highland regions of
some tropical countries, thus bringing into evidence several
previously unknown or poorly known problems regarding the crop. The
STD research project was set up in order to evaluate the major
constraints to rice cropping in the water-logged areas of Burundi
and in the irrigated and rainy ricelands of the Madagascan
highplains and to bring together several previous isolated research
efforts in order to develop consistent strategies of rice breeding
for these environments. The project brought together six
institutions: Université Catholique de Louvain (Belgium),
CIRAD-IRAT (France), Université de Bujumbura and Institut des
Sciences Agronomiques (Burundi), Centre National de la Recherche
Appliquée au Développement Rural (Madagascar) and Direction de la
Recherche Agronomique (Togo).
Agroclimatic conditions and specific pathogens were identified as
the most limiting factors. Climatic conditions related to altitude
conditions mostly determine the incidence of diseases, and cold by
itself can severely reduce fertility.
Pyricularia oryzae in the hottest regions and Pseudomonas
fuscovaginae in the coldest regions were identified as the most
important pathogens, though secondary pathogens were also
recognized. For the two above mentioned diseases, selection
constitutes the only available mean of control. While Pyricularia
oryzae is a quite well known fungal disease, P. fuscovaginae is a
poorly known bacterial disease. Therefore, most efforts have
concentrated on this pathogen, aiming to the study of its
epidemiology, the extraction and purification of toxines, the
development of serological tests and the development of inoculation
and screening procedures. In this purpose, the results suggest that
one of the isolated toxines may be used for the screening of
tolerant rice genotypes, either at the plant or the cellular level.
For cold tolerance, laboratory screening procedures, applied either
to plantlets or cell cultures, gave rather encouraging results.
They proved to correlate positively with field screening results
and, on the other hand, somaclonal variation induced by in vitro
cell culture produced, in some instances, heritable cold tolerance
expression. In fact, the breeding potential of induced variation in
tissue culture for adaptation characters such as cold tolerance is
often questioned as far as most variants are unable to pass their
tolerance to their offsprings, the same is to say, they are not
true genetic mutants. Mutants for other agronomic traits, such as
growth habit, panicle lenght, weight of 1000 grains and resistance
to Pyricularia, were also selected from in vitro cell culture.
The above mentioned insights in both the epidemiology of
Pseudomonas fascovaginae and the potential of somaclonal variation
for the isolation of useful agronomic mutants, clearly increased
the range of rice breeding technics for highland tropical regions.
Several agronomists and biologists joined in the project. In
particular, african researchers were offered training facilities
and the opportunity for a PhD degree. Moreover, annual meetings
allowed fruitful scientific exchange, and counted in the presence
of other countries, such as Rwanda, Zaire and Nepal.
Within these projects several publications have been issued.
For further information please contact:
Prof. J. Bouharmont
Université Catholique de Louvain
Address: 1, Place de l’Université
B-1348 Louvain-la-Neuve, Belgium
Phone: +32-10-47 21 11
Telex: UCLB 59037
Contract number TS2-A-046