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For standardization of definitions, maize researchers developed
a guide for identifying different growth stages of maize. Not
all plants in a field reach a particular stage at the same time.
Therefore, researchers assume that the crop reaches a specific
stage when at least 50% of the plants show the corresponding
features.
Standardization of definitions allows researchers to relate
problems, cultural practices and other agronomic observations
to specific growth stages. Researchers can also compare the phenology
of maize under different environmental conditions and experimental
treatments.
Researchers divide growth stages into two broad categories
(Table2):
- vegetative (V),
- reproductive (R).
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The following sections give more detailed description of the
growth stages: |
Section 3
Section 4
Section 5
Section 6 |
Seedling growth
Vegetative growth
Flowering and fertilization
Grain filling and maturity |
stages VE and V1
stages V2, V3 ... Vn
stages VT and R1
stages R2 to R6 |
Table 2. Growth stages.
|
Stage |
DAS* |
Features |
|
VE |
5 |
The coleoptile emerges from the soil surface |
|
V1 |
9 |
The collar of the first leaf is visible |
|
V2 |
12 |
The collar of the second leaf is visible |
|
Vn |
|
The collar of leaf number 'n' is visible. The maximum value of
'n' represents the final number of leaves, which is usually 16-23,
but by flowering, the lower 4-7 leaves have disappeared |
|
VT |
55 |
The last branch of the tassel is completely visible |
|
R0 |
57 |
Anthesis or male flowering. Pollen shed begins |
|
R1 |
59 |
Silks are visible |
|
R2 |
71 |
Blister stage. Kernels are filled with clear fluid and the embryo
can be seen |
|
R3 |
80 |
Milk stage. kernels are filled with a white,milky fluid |
|
R4 |
90 |
Dough stage. Kernels are filled with a white paste. The embryo
is about half as wide as the kernel. The top part of the kernels
are filled with solid starch |
|
R5 |
102 |
Dent stage. If the genotype is a dent type, the grains are dented.
The 'milk line' is close to the base when the kernel is viewed
from the side in both flint and dent types |
|
R6 |
112 |
Physiological maturity. The black layer is visible at the base
of the grain. Grain moisture is usually about 35% |
*DAS: approximate number of days after sowing in lowland tropics
where maximum and minimum temperatures may be 33 °C and 22
°C respectively. In cooler environments,these times are extended |