Yoshida - 1981 - Fundamentals of Rice Crop Science

30 FUNDAMENTALS OF RICE CROP SCIENCE
1.27. Tillering pattern of rice.
tile on the main culm, lacks a blade and is similar to the sheath in structure. The
prophyll, which is white, is enclosed within the leaf sheath on the main culm and is
not visible. It is the first leaf that can be seen when a new tiller comes out. Tillers
may or may not emerge from the prophyll node.
When the 13th leaf on the main culm emerges, and if tillers come from all except
the prophyll nodes, there should be a total of 40 tillers: 9 primary, 21 secondary,
and 10 tertiary (Fig. 1.27). The number of tillers shown in Figure 1.27 gives the
theoretical maximum under specified conditions. In reality, however, all the tiller
buds do not necessarily develop into tillers. Some may remain dormant. Spacing,
light, nutrient supply, and other environmental and cultural conditions affect
tillering. For example, phosphorus deficiency or deep planting impairs tillering. In
transplanted rice, about 10–30 tillers may be produced at conventional spacing,
but only 2–5 may form in direct-seeded rice.
1.6.2. Synchronous growth of a tiller, a leaf, and toots
A tiller and roots emerge from the same node at the same time. When the sixth leaf
emerges, a tiller and roots start emerging from the third node (Fig. 1.28). Similarly
when the seventh leaf emerges, a tiller and roots come from the fourth node. If
roots of a seedling are removed when the seventh leaf is about to emerge and the
plant is placed in culture solution, new roots will come only from the fourth node.
1.7. ROOTS
1.7.1. Morphology
Rice develops a radicle (seminal root), mesocotyl roots, and nodal (or adventitious)
roots (Fig. 1.29).