Evidence for the emergence of new rice types of interspecific hybrid origin in West African farmers' fields.
In West Africa two rice species (Oryza glaberrima Steud. and Oryza sativa L.) co-exist. Although originally it was thought that interspecific hybridization is impossible without biotechnological methods, progenies of hybridization appear to occur in farmer fields. AFLP analysis was used to assess genetic diversity in West Africa (including the countries The Gambia, Senegal, Guinea Bissau, Guinea Conakry, Sierra Leone, Ghana and Togo) using 315 rice samples morphologically classified prior to analysis. We show evidence for farmer interspecific hybrids of African and Asian rice, resulting in a group of novel genotypes, and identify possible mechanisms for in-field hybridization. Spontaneous back-crossing events play a crucial role, resulting in different groups of genetic diversity in different regions developed by natural and cultural selection, often under adverse conditions. These new groups of genotypes may have potential relevance for exploitation by plant breeders. Future advances in crop development could be achieved through co-operation between scientists and marginalized farmer groups in order to address challenges of rapid adaptation in a world of increasing socio-political and climatic uncertainty.
Nuijten
Edwin
E
Technology and Agrarian Development Group, Wageningen University, Wageningen, the Netherlands. Edwin.Nuijten@wur.nl
van Treuren
Robbert
R
Struik
Paul C
PC
Mokuwa
Alfred
A
Okry
Florent
F
Teeken
Béla
B
Richards
Paul
P
D000349:Africa; D000383:Agriculture / Q000379:methods*; D054458:Amplified Fragment Length Polymorphism Analysis; D002678:Chimera; D003433:Crosses, Genetic; D005838:Genotype; D005843:Geography; D006824:Hybridization, Genetic; D009693:Nucleic Acid Hybridization; D012275:Oryza / Q000235:genetics*; D010802:Phylogeny; D013045:Species Specificity