Abstract
Using each of the 40 varieties of African and Asian floating rice, internode elongation was investigated under submerged and non-submerged conditions. Under submerged conditions, the position of the lowest elongated internode (LEI) varied from the eighth to the thirteenth internode in both rices. Under non-submerged conditions, variation of the LEI position was from the ninth to the fourteenth internode in African floating rice and from the eighth to the thirteenth internode in Asian floating rice. The difference in the LEI position between submerged and non-submerged conditions was less than one internode in the Asian floating rice varieties, while it was 1.1-3.0 internodes in most varieties of the African floating rice. On the other hand, the average LEI length under submerged conditions was nearly the same between both rices, and under non-submerged conditions, the length of the African floating rice was one-third that of the Asian floating rice. Further, of the African fLoating rice with a shoft LEI, the lengths of some upper internodes of the LEI were also short. These results show that, under non-submerged conditions, the elongation ability of African floating rice is inferior to that of Asian floating rice.
