Al Hakimi Khalid Ali Ahmed
Abstract
This study discusses the research of photoperiodic reaction A. hypochondriacus L. variety No. 1008, A. cruentus L.
variety No. 17 and A. hypochondriacus x A. hybridus variety Koniz.
The field experiments manifested critical day length longer than l6 hours. Also the photoperiodic experiment with
special equipment showed that all three varieties of amaranth classified in literature as short-day plants are not
strictly, in reality, short-day plants. However, the compulsary short-day plants are very tolerant to the length of the
day. The observed species and varieties behaved under the conditions of mild climate (50°n.lat.) as plants
responsive slightly to shorter days as plants facultatively photoperiodically sensitive which burst into bloom and
produce seeds also during the summer period with longer days. Such as this it is possible to explain the successful
cultivation of grain amaranths in the Czech Republic.
Key words:
Amaranthus hypochondriacus, Amaranthus cruentus, Amaranthus hypochondriacus x Amaranthus
hybridus, photoperiodic reaction, critical day length, facultatively short-day plants.