SECONDARY CHEMISTRY OF HYBRID AND PARENTAL WILLOWS - PHENOLIC GLYCOSIDES AND CONDENSED TANNINS IN SALIX SERICEA, S-ERIOCEPHALA, AND THEIR HYBRIDS

Salix sericea and S. eriocephala differ markedly in secondary chemistr y. S. sericea produces phenolic glycosides, salicortin and 2'-cinnamoy lsalicortin, and low concentrations of condensed tannin. In contrast, S. eriocephala produces no phenolic glycosides, but high concentration s of condensed tannins. Hybrid chemistry is intermediate for both type s of chemicals, suggesting predominantly additive inheritance of these two defensive chemical systems from the parental species. However, th ere is extensive variation among hybrids. This variation may be due to genetic variation among parental genotypes, which genes were passed o n, or to subsequent back-crossing. The differences in chemistry are li kely to exert a strong effect on the relative susceptibility of hybrid and parental willows to herbivores.