Hybridization between Fagopyrum (Polygonaceae) species native to China

Thirty-eight crosses between seven Fagopyrum species native to China were s tudied. Following normal pollination, there were very low inter-group cross abilities (only 0-3%) between five species in the large-achene group and tw o species (F. gracilipes and F. pleioramosum) in the small-achene group, an d high (15-50%) within the large-achene group, i.e. F. esculentum, F. talar icum, F. zuogongense, F. pilus and F. megaspartanium. Crosses between vario us types of flowers (homostyle, heterostyle etc.) suggested that the intras pecific incompatibility also occurs in interspecific crosses. The hybrid se eds obtained from interspecific crosses all withered or shrivelled and lack ed activity. Only one hybrid plant was obtained, tetraploid F. esculentum x tetraploid F. zuogongense. The hybrid displayed anomalous behaviour at mei osis, pollen grain sterility and withering of achenes, confirming the genet ic differences between F. esculentum and ii zuogongense. The results suppor t the hypothesis that F. megaspartanium and F. Pilus are the possible ances tors of cultivated buckwheat. (C) 1999 The Linnean Society or London.