Abstract:
Two cultivars (Polish – Bursan and American – Tennessee 90) were
topped at beginning of flowering stage. 4 levels of topping were employed:
high (inflorescence with 2 leaves removed); mean (topping, leaving 14 leaves
on plants); low (leaving 12 leaves); very low (leaving 10 leaves). Control
object – plants without topping. Suckers appearing on topped plants were
removed successively by hand. The reaction of both cultivars on topping was
similar: high and mean toppings resulted in slight increase of leaves yields,
while low and very low toppings –decrease (significant in case of Tennessee
cv). In all cases, topping modified quality of leaves, the most profound being
when low and very low topping was applied. The modification referred to
booth: physical features of leaves as well as their chemical composition. As
regards physical properties – leaves were bigger, had higher weight of “leaf
body” and were characterized by smaller contribution of midrib. In range of
chemical composition, leaves of topped plants contained much more nicotine
and lesser amount of ash..
