Tagging and mapping of a new elongated-uppermostinternode gene - eui2(t) - using AFLP, RFLP, and SSR techniques.

A new elongated-uppermost-internode gene, eui2(t), was identified from a mutant, XQZeB-2. Using AFLP and bulked segregant pools from F 3 progenies of the cross XQZeB-2/Aijiaonante, approximately 8,960 AFLP loci were screened with 128 primer combinations. Four polymorphic AFLP products were identified and designated as EM436, EM444, EM521, and EM527, respectively. Among them, EM521 was tightly linked to the eui2(t) gene by segregation analysis. EM521 was mapped on chromosome 10. Meanwhile, four SSR markers, RM258, RM269, RM271, and RM304, with a genetic distance to eui2 of 12.0, 12.9, 33.1, and 1.4 cM, respectively, were screened by microsatellite analysis. The results of microsatellite analysis and the mapping of AFLP marker EM521 confirmed that eui2(t) was located in the middle of the long arm of chromosome 10. The identification of the eui2(t) gene makes it possible to develop hybrid rice with sterile (A) and restorer lines (R) possessing different eui genes simultaneously, which would result in a reduced application of GA 3 for both parental lines.