A study of resources of Fagopyrum (Polygonaceae) native to China

Morphology, taxonomy, reproductive biology, esterase isozyme patterns and c hromosome number were studied in 16 accessions of cultivated and wild buckw heat native to Tibet, Sichuan, Guizhou and Yunnan. Among these are four est ablished species: Fagopyrum esculentum, F. tataricum, F. pleioramosum and F . gracilipes. The first three species are diploid (2n=16) and the last one is tetraploid (2n=32). In addition to the above, three new species are desc ribed: F. zuogongense, F. megaspartanium and F. pilus. There are clear diff erences in esterase isozyme patterns between these species. The zymoographs of esterase isozyme of diploid B megaspartanium (native to Sichuan) and F. pilus (native to Tibet) are similar to those of I;: esculentum and F. tata ricum respectively. F. gracilipes, in the small achene group of the genus, has a zymograph of esterase isozyme that is very different from the species in the large-achene group. The diploid accessions of F. pilus and B megasp artanium may be ancestors of cultivated buckwheat. (C) 1999 The Linnean Soc iety of London.