ABSTRACT
The developmental cycle of rye can be divided into 12 stages: During stage 1, the growing point is not differentiated. In stage 2, the primordia of stems, nodes, and internodes are formed in the growing point. Winter rye, usually planted in autumn and moderate climate, enters the winter period in stage 2. In stage 3, the growing point differentiates into further segments, which are primordia of spikelets. During this period, nitrogen supply has a positive effect on the formation of a large number of spikelets, which leads to the subsequent formation of longer spikes with a greater number of owers and grains. A further differentiation of growing points takes place during stages 3 and 4, in which ower primordia are formed. This process takes place in early spring. During the formation of spikelet primordia in the upper part of the spike, organs of generative reproduction (owers) are formed in the middle portion. The plants then enter stage 5 of organogenesis. Under conditions of long days and with a poor nitrogen supply, this process is relatively fast. Meiotic divisions of pollen mother cells and the formation of tetrads, the embryo sac, and the egg take place during stages 6 and 7 of organogenesis. Stage 7 is characterized by extensive elongation growth during which pronounced elongation of shoot internodes takes place. In stage 8, the plants ear and subsequently ower. Fertilization and maturation of caryopses and plants then follow in the remaining four stages of development.
