Agriculture Reference
In-Depth Information
Stage
Description
Measurement Characteristics
Germination
Feekes—no stage
Start of imbibition is when the seed begins to
swell
Zadoks—01 (start of imbibition), 03 (imbibition complete), 05
(radicle emerged from caryopsis), 07 (coleoptile emerged
from caryopsis)
Emergence
Feekes—no stage
Beginning of emergence is when the fi rst true
leaf emerges through the coleoptile and tip is
visible above the soil surface
Zadoks—09 (leaf just at coleoptile tip)
Tillering
Feekes—1.0 (main shoot only), 2.0 (beginning of tillering)
Beginning of tillering is when the fi rst tiller is
visible (likely T0 or T1)
Zadoks—20 (main shoot only), 21-29 (main shoot and 1 tiller
through 9 tillers)
Single ridge
Neither scale describes
Begins when the shoot apex shape changes from
dome to more elongated, and leaf primordia
begin to form a ridge around apex (Fig. 2.1)
Double
ridge
Neither scale describes
Begins when the formation of double ridges
(bottom ridge
spikelet)
around the apex occurs (Fig. 2.1)
=
leaf, top ridge
=
Terminal
spikelet
Neither scale describes
When the apical spikelet primordium appears
and noted by rotation of 90 º from plane of
previous spikelets
Internode
elongation
Neither stage clearly notes the beginning of internode
elongation; rather it is assumed to be in stem elongation
when node(s) are visible above the soil surface.
Beginning of internode elongation is when the
fi rst node is visible (but normally will be
below the soil surface)
Feekes—6 (fi rst node of stem visible at base of shoot above soil
surface), 7 (second node visible, next to last leaf just visible)
Zadoks—31 (fi rst node detectable) through 36 (sixth node
detectable)
Jointing
Feekes—implicitly assumed to be when the fi rst node is visible
above the soil surface (Stage 6) and when plant growth habit
changes from prostrate to upright
Occurs when fi rst node is visible above the soil
surface
Zadoks—not described
Flag leaf
Feekes—8 (last leaf visible but still rolled, ear beginning to
swell), 9 (ligule of last leaf just visible), 10 (sheath of last leaf
completely grown out, ear swollen but not yet visible)
Cannot know if it is the fl ag leaf while it is
appearing; fl ag leaf growth is considered
complete when the ligule is visible and no
new leaf is emerging
Zadoks—39 (fl ag leaf ligule/collar just visible), 41 (fl ag leaf
sheath extending, booting)
Booting
Feekes—see above for 8-10
As booting is a continuum, begins when the fl ag
leaf ligule is visible and ends when heading
begins
Zadoks—41 (see above), 43 (boot just visibly swollen), 45 (boot
swollen), 47 (fl ag leaf sheath opening), 49 (fi rst awns visible)
Heading
Feekes—10.1 (fi rst ears just visible), 10.2 (1/4 of heading
process completed), 10.3 (half completed), 10.4 (3/4
completed), 10.5 (all ears out of sheath)
Measure based on one infl orescence (main stem
best), and heading begins when fi rst spikelet
is visible (awns not considered) and ends
when the infl orescence has completely
emerged from the fl ag leaf
Zadoks—50 (fi rst spikelet of infl orescence just visible), 53 (1/4
of infl orescence emerged), 55 (half of infl orescence emerged),
57 (3/4 emerged), 58 (infl orescence completely emerged)
Anthesis
Feekes—10.5.1 (beginning of fl owering, 10.5.2 (fl owering
complete to top of ear), 10.5.3 (fl owering over at base of
ear), 10.5.4 (fl owering over, kernel watery-ripe)
Measure based on one infl orescence (main stem
best); ends when fi rst anther (yellow) is visible
on infl orescence, and ends when no more
anthers appear on the infl orescence
Zadoks—61 (beginning of anthesis), 65 (anthesis halfway), 69
(anthesis complete)
Physiological
maturity
Feekes—11.1 (milky ripe), 11.2 (mealy ripe, contents of kernel
soft but dry), 11.3 (kernel hard, diffi cult to divide by
thumbnail), 11.4 (ripe for cutting, straw dead)
No scale defi nitively identifi es when
physiological maturity is reached (defi ned as
maximum dry weight); Hanft and Wych
(1982) indicate when all components of the
spike (glumes, paleas, lemmas), internode
tissue, and leaves have lost all green color
Zadoks—a series of stages from milk development (77-77),
dough development (83-87), and ripening and seed
dormancy (91-99)
Developmental stage descriptions derived from Bauer et al. (1983) and the original references. Some developmental stages are
shown in Fig. 2.1.
