Yam (<i>Dioscorea rotundata</i> Poir.) Displays Prezygotic and Postzygotic Barriers to Prevent Autogamy in Monoecious Cultivars
Narcisse Denadi,
Mounirou Yolou,
Ayènan Eric Dadonougbo,
Jeanne Zoundjihékpon,
Alexandre Dansi,
Christophe Gandonou,
Muriel Quinet
Affiliations
Narcisse Denadi
Groupe de Recherche en Physiologie Végétale, Earth and Life Institute, Université Catholique de Louvain, B-1348 Louvain-la-Neuve, Belgium
Mounirou Yolou
Laboratoire de Génétique Ecologique, Faculté des Sciences et Techniques, Université d’Abomey-Calavi, Cotonou 01BP4521, Benin
Ayènan Eric Dadonougbo
Laboratory of Biotechnology, Genetic Ressources and Plant and Animals Breeding (BIORAVE), National University of Sciences Technology, Ingeneering and Mathematics, Dassa-Zoumé 01BP14, Benin
Jeanne Zoundjihékpon
Laboratoire de Génétique Ecologique, Faculté des Sciences et Techniques, Université d’Abomey-Calavi, Cotonou 01BP4521, Benin
Alexandre Dansi
Laboratory of Biotechnology, Genetic Ressources and Plant and Animals Breeding (BIORAVE), National University of Sciences Technology, Ingeneering and Mathematics, Dassa-Zoumé 01BP14, Benin
Christophe Gandonou
Laboratoire de Physiologie Végétale et d’Etude des Stress Environnementaux, Faculté des Sciences et Techniques, Université d’Abomey-Calavi, Cotonou 01BP526, Benin
Muriel Quinet
Groupe de Recherche en Physiologie Végétale, Earth and Life Institute, Université Catholique de Louvain, B-1348 Louvain-la-Neuve, Belgium
Cultivated yam (D. rotundata) is a staple tuber crop in West Africa whose sexual reproduction control remains largely unknown despite its importance for plant breeding programs. In this paper, we compared self-pollination, intracultivar cross-pollination and intercultivar cross-pollination in three monoecious cultivars (Amoula, Heapala and Yassi). Results showed that pollen viability (49%) and stigma receptivity (40%) were similar in monoecious and dioecious plants, suggesting that autogamy could occur in monoecious plants. However, fruit and seed sets were significantly lower after self-pollination compared to cross-pollination. Overall, autogamy reached 11% and pollen lability was almost zero (D. rotundata even after cross-pollination as fruit and seed set did not exceed 18% and 13% respectively. Moreover, comparison between intracultivar cross-pollination and self-pollination revealed intravarietal genetic diversity inside the analyzed yam cultivars. Overall, our results showed that D. rotundata has a very low tolerance to autogamy in monoecious cultivars and has developed pre- and postzygotic mechanisms to limit selfing.
