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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: 2 May 1996 11:01:23 GMT
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Article: 12273 of alt.sustainable.agriculture
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Newsgroups: alt.sustainable.agriculture
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Organization: Centro Informatico Cientifico de Andalucia
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.
Contract number TS2-A-046
For further information please contact:
Prof. J. Bouharmont
Université Catholique de Louvain
Address: 1, Place de l’Université
B-1348 Louvain-la-Neuve, Belgium