マダガスカルのイネと稲作(<特集>マレー世界のなかのマダガスカル)

Abstract

This report compiles the results of field research conducted in Madagascar in 1986 and the analysis of rice varieties collected there, and aims to clarify the genealogy of rice culture in Madagascar in comparison with rice and rice culture in the Asian rice-growing countries. The area I visited is divided into four regions according to natural conditions and cultural background : the northern-central east coast, the southern east coast, the Central Plateau, and the northwest. Observation of conventional farming practices throughout the regions revealed a clear difference in rice-growing techniques between the east coast regions and the others. The former show a close resemblance to those of the Southeast Asian archipelago, while the latter include techniques which are thought to derive from Indian rice culture. The regional differences in rice-growing techniques suggest that rice culture was introduced into Madagascar in two currents : the 'Malay' current, which is evident predominantly in the east coast regions, and the 'Indian' current, which appears to have arrived later and infiltrated most of the country, replacing the 'Malay' type of culture. A total of 82 varieties collected in Madagascar was analysed for the following characters : grain type, coloration of grains by phenol reaction, degree of destruction of endosperm by KOH solution, and such growth characters as plant height, tillering ability, heading date, size of flag leaf, etc. Based on the intervarietal and regional variations of these characters, it is concluded that there are two major types of varieties derived from Asian origins : javanica and indica. The javanica varieties consist mainly of upland rice and are widely grown in the east coast regions, while the indica varieties consist of wet rice and are grown all over the country. The wider distribution of the indica varieties is attributable to the rather recent expansion of wet-rice culture to various areas of the island. In conclusion, it is suggested that there were two possible routes of introduction of rice culture into Madagascar : direct transfer of the 'Malay' type of rice culture to the east coast across the Indian Ocean from the Southeast Asian archipelago, and the later introduction of the 'Indian' type of rice culture, probably to the northern part of the island, from the Indian subcontinent.