GENETICS OF FERTILITY RESTORATION IN THE C-GROUP OF CYTOPLASMIC MALE STERILITY IN MAIZE

摘要

The genetics of fertility restoration of cms -C group cytoplasm of maize was studied using crosses involving stable maintainer lines and lines that restored full pollen fertility. Pollen fertility in the sources of cms -C sterile cytoplasms studied was restored by a single dominant restorer ( Rf4 ) gene. The fertility restoration was sporophytic. Allelism tests among five restorer lines showed that they all apparently carried the same alleles ( Rf4 Rf4 ). Similar tests also demonstrated that seven nonrestoring maintainer lines had apparently the same genotype ( rf4 rf4 ), although a partial "late break" of fertility was observed at low levels in some maintainer crosses. Comparative studies among different cms -C sources (C, Bb, ES, PR and RB) indicated that similar inheritance of fertility restoration was involved. The data indicated that a single, dominant Rf gene is involved in the restoration of several C-group cytoplasms, at least in the lines studied here. This is the first single-gene, sporophytic restorer system described in maize to date.