Corn Growth Staging Using the Leaf Collar Method

Lindsay Overmyer Author

05/11/2021 Added

105 Plays

Description

Corn growth staging using the leaf collar method provides an overview of staging corn from emergence (VE) to the abscission layer (R6).

Searchable Transcript

Search:

[00:00:09.350]Corn at Growth Staging Using
[00:00:11.030]the Leaf Collar Method.
[00:00:13.950]Understanding the growth stages
[00:00:15.720]of corn Zea mays is important
[00:00:17.810]for management decisions regarding fertilizer,
[00:00:20.850]irrigation, and pesticide applications.
[00:00:24.060]The leaf collar staging method is the most
[00:00:26.690]commonly used method, as it is used by many in the industry.
[00:00:31.040]For this method, plant growth stages are broken down
[00:00:34.890]into two main phases, vegetative and reproductive.
[00:00:39.670]During vegetative growth, the leaf collar method
[00:00:42.290]of staging corn involves counting leaves
[00:00:44.950]showing visible collars.
[00:00:46.940]A leaf collar is located at the base of the leaf blade
[00:00:50.800]where it wraps around the stem,
[00:00:52.590]and it can be identified as a visually distinct band.
[00:00:57.000]Stages during vegetative growth will include a V
[00:01:00.650]for the vegetative phase,
[00:01:02.390]and the number of leaf collars visible on the plant.
[00:01:05.900]Once the ear and its silks are visible,
[00:01:08.200]the plant has reached the reproductive growth phase
[00:01:10.900]and staging on the plant focuses
[00:01:13.180]on ear and kernel development on the primary ear.
[00:01:16.680]The primary ear is the uppermost ear on the plant.
[00:01:20.700]When the corn seed germinates and the coleoptile emerges
[00:01:24.070]through the soil's surface,
[00:01:25.480]the stage is vegetative emergence or VE.
[00:01:28.890]When the leaf collar of the first true leaf is visible,
[00:01:32.230]the stage is V1.
[00:01:33.930]This first leaf has a rounded tip,
[00:01:36.100]but all remaining leaves produced will have a pointed tip.
[00:01:40.160]This is a V5-stage plant,
[00:01:42.900]as the leaf collars of five leaves are visible.
[00:01:46.820]The growing point of corn is
[00:01:49.190]below the soil's surface until V6.
[00:01:52.690]For the later stages of corn,
[00:01:54.830]it may be difficult to establish the exact number of leaves
[00:01:58.980]because the lower leaves may have dried up and fallen off.
[00:02:03.270]Under these conditions, if leaf stage accuracy is critical,
[00:02:07.250]the exact stage can be determined by dissecting the stalk
[00:02:11.130]and counting the thickened internal leaf nodes.
[00:02:15.310]The vegetative tassel stage
[00:02:17.490]or VT is the last vegetative stage.
[00:02:21.220]The plant is at VT when all branches
[00:02:24.240]of the tassel are fully visible
[00:02:26.570]and not held within the upper most leaves.
[00:02:30.510]The first stage of the reproductive phase
[00:02:33.170]is reproductive silking or R1.
[00:02:36.250]This occurs when the silks extend outside the ear husk.
[00:02:40.780]This is a critical time for the plant
[00:02:43.000]because pollination and fertilization occur.
[00:02:46.410]Pollination is the transfer of pollen grains,
[00:02:49.630]the male reproductive cell,
[00:02:51.610]from the tassel to the silks, the female reproductive cell.
[00:02:55.340]Every silk is attached to an ovary and is receptive
[00:02:58.680]to pollen for at least five days after emerging.
[00:03:02.250]The first silks to emerge are those attached
[00:03:05.060]to potential kernels at the base of the ear.
[00:03:08.420]The silks at the tip of the ear emerge later,
[00:03:12.100]and if they do not receive pollen,
[00:03:14.120]they will not develop into an embryo.
[00:03:16.850]The R2 stage is referred to as the blister stage
[00:03:20.300]because the top of the kernels resemble a blister
[00:03:23.910]where the silks were attached.
[00:03:25.690]R3 is known as the milk stage
[00:03:28.430]because the kernels are filled with a milky material,
[00:03:31.690]and when pressure is applied,
[00:03:33.350]the kernel will easily pop and expose its milky contents.
[00:03:37.920]The dough stage or R4 is identified
[00:03:41.350]when the interior contents
[00:03:43.070]of the kernel has a consistency similar to dough.
[00:03:46.790]At dent, or reproductive stage five, or R5,
[00:03:50.840]the moisture content in the kernel has declined
[00:03:53.630]to about 60% and this results in a dent in most kernels.
[00:03:59.500]However, dry matter content of the kernel continues
[00:04:03.610]to accumulate considerably
[00:04:05.420]as the kernels continue to lose moisture.
[00:04:08.560]Physiological maturity or R6 is the final gross stage
[00:04:12.580]of corn, and kernel moisture content is about 30%.
[00:04:17.340]At R6, an abscission layer, also called black layer,
[00:04:21.610]has formed at the base of the kernel,
[00:04:24.150]and the kernel does not receive further nutrients
[00:04:26.780]from the plant.
[00:04:28.280]Understanding these stages
[00:04:29.750]of growth is important for management decisions.

The screen size you are trying to search captions on is too small!

You can always jump over to MediaHub and check it out there.

Tags:
corn
corn growth stages
leaf collar method
maize
zea mays

Comments

0 Comments

Corn Growth Staging Using the Leaf Collar Method

Description

Searchable Transcript

Comments icon comment

Related Channels

Comments