African Journal of Biotechnology Vol. 6 (17), pp. 2014-2022, 5 September 2007   

ISSN 1684–5315 © 2007 Academic Journals        

Full Length Research Paper

Molecular profiling of an interspecific rice population derived from a cross between WAB 56-104 (Oryza sativa) and CG 14 (Oryza glaberrima)

K. Semagn¹, M. N. Ndjiondjop², M. Lorieux³, M. Cissoko², M. Jones⁴ and S. McCouch⁵*

¹International Crops Research Institute for the Semi-Arid Tropics, P. O. Box 39063, Nairobi, Kenya.

²Africa Rice Center (WARDA), 01 BP 2031, Cotonou, Benin.

³ IRD/CIAT (Institut de Recherche pour le Développement/International Centre of Tropical Agriculture), A.A. 6713, Cali, Columbia.

⁴ Forum for Agricultural Research in Africa, PMB CT 173 Cantonments, Accra, Ghana

⁵Plant breeding, 162 Emerson hall, Cornell University, Ithaca New York 14 853 – 19 01.

*Corresponding author. E-mail: srm4@cornell.edu. Tel: (607) 255 0420. Fax: (607) 255 6683.

Accepted 7 May, 2007

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 (~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.

Key words: New Rice for Africa (NERICA), Oryza sativa, Oryza glaberrima, graphical genotype, microsatellite markers, introgression lines.