A Female Sterile Variant in Rice

The nature of sterility in a line of rice G2250 isolated as a rogue from a field of fertile rice was studied cytologically and genetically. The variety Bluebelle was used as the fertile control parent. Reduced percentage of seed set and aborted seeds were observed when G2250 was used as the maternal parent in crosses with Bluebelle. Reciprocal crosses, however, gave normal seed development. The F1 hybrids (BB × G2250) segregated for fertile and sterile plants. Pollen development was normal in both G2250 and the F1 hybrids. Backcrossing the F1 hybrids with G2250 as maternal parent caused a reduction in seed set. Backcrossing the F1 hybrids with Bluebelle as the maternal parent gave rise to normal seed set. However, seed set was drastically reduced when the sterile F1 hybrids were used as the maternal parent irrespective of the pollen parent. The fertile F1 hybrids bred true for fertility while the sterile F1’s segregated into approximately three steriles to one fertile. The results suggested that at least one dominant gene controlled female sterility in G2250 which was heterozygous for the gene.