Mapping and molecular marke-based genetic analysis for efficient hybrid rice breeding

摘要

Work in mapping and molecular marker-based genetic analysis of fertility-related genes currently employed in hybrid rice breeding is reviewed. This includes genes for fertility restoration of wild abortive (WA) cytoplasmic male sterility (CMS), photoperiod-sensitive genic male sterility (PGMS), and thermosensitive genic male sterility (TGMS),and genes for wide compatibility. Studies showed that fertility restoration of WA CMS is controlled by at least two independent dominant genes (RF-1 and RF-3). The chromosomal locations of these two genes need to be resolved further. Single-locus inheritance has been observed for all TGMS mutants. The TGMS genes of two independently derived mutants were mapped to two different chromosomes. Studies demonstrated a relatively simple mode of inheritance of PGMS.But the chromosomal locations of the PGMS genes were complicated.A single wide compatibility gene having a large effect on the fertility of indica/japonica F 1 hybrids has been confirmed in a range of indica/japonica crosses based on the results from studies on inheritance and mapping. Another locus modifying hybrid fertility was also detected in the presence of the wide compatibility gene. Future efforts should be directed to reconciling the discrepancies between the results of mapping and inheritance studies in some of the systems and identifying markers tightly linked to the genes of interest to facilitate marker-aided selection.