Allelopathic plants. 3. Velvetleaf (Abutilon theophrasti Medic.)

The genus Abutilon has more than 80 spp., distributed in tropical a,ld subt ropical countries. Some spp. (e.g. A. asiaticum. A. indicum. A. persicum. A . theophrasti) are cultivated as crops for fibre and medicines in China and Tibet. The information about distribution of its 24 spp. is available. Abu tilon theophrasti is major weed spp, which reduces the crops yields. It is propagated through seed. Bioassays, pot culture and field studies revealed that all plant parts viz., seed, shoot, root are toxic to crop plants and s ome fungal spp. Its glandular trichomes on stem and petioles exude very phy totoxic exudates. The quantity and phytotoxicity of exudate vary with site and climatic conditions. The allelochemicals have been identified as amino acids, phenolic compounds, flavonoids and terpenoids, phytotoxic to germina tion and seedling growth of crops and have fungitoxic effects. The fungitox ic properties needs to be exploited for management of pathogens.