Abstract

S. O. Abebrese, R. Akromah and P. K. A. Dartey

Some selected first and second generation upland NERICAs (New Rice for Africa, genetic interspecific materials derived from successful crossing of the two cultivated rice species Oryza sativa and Oryza glaberrima) were intercrossed to find out their level of cross-compatibility and the extent of sterility in the NERICAs. All hybrids were partially sterile and showed significant differences in their seed set (0.6 to 33.09%). The direction of crossing partly affected crossability in the NERICAs. Hybrids from crosses that maintained O. glaberrima cytoplasm, showed significantly higher (p 0.05) seed fertility than those that maintained O. sativa cytoplasm. Pollen fertility tests indicated reduced pollen viability in the hybrids. Seed set was improved (up to 65%) when hybrids were backcrossed to either parent. Cytoplasmic factors probably affected the degree of sterility in the NERICAs. Within the selected NERICAs improvement could therefore be possible through conventional crosses and best through backcross breeding.