Molecular profiling of an interspecific rice population derived from a cross between WAB 56-104 (Oryza sativa) and CG 14 (Oryza glaberrima)
Semagn, K.; Ndjiondjop, M. N.; Lorieux, M.; Cissoko, M.; Jones, M.; McCouch, S.
African Journal of Biotechnology 6(17): 2014-2022
NERICA rices are interspecific inbred progeny derived from crosses between Oryza sativa x O. glaberrima. In this study, we evaluated 70 BC2 interspecific lines, developed by crossing a tropical japonica variety (WAB 56-104) as the recurrent parent to an O. glaberrima variety (CG 14) as the donor parent, followed by the use of anther culture to derive doubled haploids (DH) ( 26 lines) or eight generations of inbreeding to fix the lines ( 44 lines). Seven of these BC2 derived inbred lines have been released as NERICA 1 - NERICA 7. This study examined the relative contribution of each parent and the extent of genetic differences among these 70 sister lines using 130 well-distributed microsatellite markers which cover 1725 cM of the rice genome. The average proportion of O. sativa recurrent parent genome was 87.4% ( 1,508 cM), while the observed average proportion of O. glaberrima donor genome was 6.3% ( 108 cM). Non-parental alleles were detected in 83% of the lines and contributed an average of 38 cM per line (similar to 2.2% of genomic DNA). Lines that had undergone eight generations of inbreeding in the field contained significantly more non-parental alleles (av. 2.7%) compared to the DH lines (av. 1.3%) that were developed from BC2 anthers. Using both cluster and principal component analyses, two major groups were detected in these materials. The NERICA varieties ( NERICA 1 to 7) clustered in one group while the remaining 63 lines clustered in another group, suggesting that the second group may offer significant opportunities for further selection and variety development.