Vol. 15—1961 - NorthEastern Weed Science Society

operations are still able to produce seed. l.\fhenthe required short dav
conditions or-evadL, seed heads will be formed even thowsh nlants may still
be quite small.
The seed producing potential of yellow foxtail was strikingly shown
by the "';)roduction of very short seed heads from stubble :3weeks follO\dng
4.u~ust .29 eLdpcdng of a stand in full bloom. Culms cut by tilla!!e and
partially buried may strike root and subsequently produce seed heads.
Repeated clip'Oing or tillage is required to completely stop seed formation
by foxtail.
Summary
A study of the germination and growth characteristics of yellow foxtail
(Setaria glauca (1.) Beauv.) has explained in part the '\'lell recognized
uersistence of this species.
A post-harvest dormancy assures that the seed will not germim te
orior to the following spring when its life cycle can be completed. Of a
large number- of seed treatments' adme,1 at inducing germinq,tion, scarification
proved to be the most effective. Lack of water penet.ratd on to the embryo
is at least one factor in the dormancv found in the first few weeks follo\'ling
harvest.
Field grovm 'Olanta were found to be prolific seed producers. Many
uncrowded plants produced over 8000 seed heads per plant. Dav length ..not
plant size, was found to control the time of seed head production. Th~s
short 1ay response ensures that 'Plants will set seed before the grovin ....season
is tennina ted.