The present work was conducted during two successive selasons of
199912000 and 200012001 to study the effect of ethrel, cycocel and polyamine on
g~h, yield and chemical constituents on onion (Allium cepa L.). The results suggested that. spraying onion plants twice With all growth
regulators increased plant height. number or leaves and leaves weig~1. While.
application of growth regulators with one or two sprays increased length, dla ster as
well as weight. of onion bulb. Moreover. spraying onion plants twice with growth
regulators had a favourable effed on yield, especially with cycocel and polyaTine. Foliar spray of all growlh regulators with one dose induced Ih highest
increase in the soluble sugars. On the other hand, sprayed with two doses ihcreased
other chemical constituents. In most cases spraying ethryl and polymine at high level
and cycocel at medium level may result in a promising chemical constituents.