Germination, Host Preference, and Phenolic Content of Witchweed (Striga bermonthica) Seed Populations'

Phenolic content, germination percentage, and host preference were compared among 11 seed populations of witchweed (Striga hermonthica (Del.) Benth. #3 STRHE). Significant differences in germination percentage occurred among the seed populations after preconditioning by their exposure to different durations of warm-moist conditions. Greatest percentage of seed germinated after 8 days of pre- conditioning. Preconditioning for more than 16 days reduced percentage germination. The host specificity range of witch- weed seed populations that parasitized pearl millet (Penni- setum americanum (L.) K. Schum) was broader than were those seed populations that attacked sorghum (Sorghum bicolor (L.) Moench.). Results of thin-layer chromatog- raphy indicated large variations in phenolic content among the witchweed seed populations. Additional index words. Germination inhibitors, STRHE.