Test on Indica-compatibility of Candidate Indica-compatible Japonica Lines in Rice

[Objective] The aim was to breed the indica-compatible japonica lines (ICJL). [Method] The indica-compatibility of 5 candidate ICJLs were tested based on the pollen fertility and spikelet fertility of F1 hybrids with 6 indica testers,6 japonica testers and 6 and middle testers. [Result] Candidate ICJL G2123, G2417, G2410 and G3005 were grouped into the exceptionally indica-compatible lines based on their high indica-compatibility and low japonica-compatibility. Candidate ICJL G2615 was grouped into the non-compatible lines on their low indica-compatibility and low japonica-compatibility. The testers, fertility identification standards, test methods of pollen fertility and spikelet fertility were discussed when the compatibility of CICJL was tested. The reason of the indica-compatibility in G2417 was analyzed.[Conclusion] The selfing seed setting rate (spikelet fertility) of G2417 was 95.1% and the crossing seed setting rate (spikelet fertility) of F1 hybrid between G2417 and indica testers was 94.9%. G2417 had high indica-compatibility and good synthesis-character.