Yoshida - 1981 - Fundamentals of Rice Crop Science

GROWTH AND DEVELOPMENT OF THE RICE PLANT 53
Table 1.14. Developmental stages and morphological characteristics. a
Morphological characteristics
Developmental
stages
Leaf no. Exsertion of n th Panicle
index leaf counted length
from the top
1. Necknode differentiation
stage
2. Branch differentiation
stage
a. Primary branch
differentiation stage
b. Secondary branch
differentiation stage
3. Spikelet differentiation stage
a. Early stage
b. Middle stage
c. Late stage
4. Pollen mother cell
differentiation stage
5. Reduction division stage of
pollen mother cell
6. Extine formation stage
7. Ripe pollen stage
76–78
80–83
85–86
87
88–90
92
95
97
100
100
4th leaf
3rd leaf
2nd leaf
Flag-leaf
0.5–0.9 mm
1.0–1.5 mm
1.5–3.5 mm
3.5–15.0 mm
1.5–5.0 cm
5.0–20.0 cm
Full length
Full length
a
Modified from Matsushima (1970).
When a variety has more or less than 16 leaves on the main culm, its leaf number
index must be corrected for a deviation from 16 so that Table 1.14 can be used for
varieties of any leaf number. The correction factor is calculated as:
Correction factor (C.F.) = (100- leaf number index) ×
16 - total number of leaves
10
Calculation of the corrected leaf number index then becomes:
Example:
(1.15)
Corrected leaf number index = leaf number index + C.F. (1.16)
Total number of leaves on main culm: 14
Plant age: 12.6 leaf stage
Leaf number index: 12.6/14 = 90
16 – 14
Correction factor: (100 - 90) ×
=2
10
Corrected leaf number index = leaf number + C.F.
= 90 + 2
= 92
The leaf number index can be converted into leaf number counted from the flag leaf
as shown in Table 1.14.