Studies on Agronomic Traits of African Rice(Oryza glaberrima Steud.)

The changes in growth, dry matter productivity and yielding ability in the course of domestication from O.breviligulata to African rice(O.glaberrima)were examined. Between the two rice species, differences were hardly detected in plant height, culm length and final leaf number, although O.breviligulata had a wider variation of these characteristics as compared with African rice. The shorter strains tended to produce more tillers at the maximum tiller number stage, and the high tillering capacity was correlated with a low percentage of productive tillers, although the strains having a small number of grains per head showed a high percentage of productive tillers, in both species. No significant difference was detected between the two species in straw weight at maturity, and the differences in straw weight among strains were attributed to the differences in days required from transplanting to heading and to plant height. No significant difference between the two species was observed in top and total weights. The grain number per head was conversely related with panicle number in both species. Although the percentage of ripened grain tended to be slightly lower in O.breviligulata than in African rice, this may be attributed partly to the difference in grain number per hill. Single grain weight in O.breviligulata was nearly equal to that in African rice. These results suggest that agronomic traits such as growth, dry matter productivity and yielding ability have been changed only slightly in the course of domestication from O.breviligulata to African rice.