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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.

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