October, 1995 - Corrections and additions in this version supercede the publications Montana State University Misc. Bulletin 4387, University of Idaho Misc. Series 118 and previous World Wide Web editions. This document has been formated for optimum viewing using the Netscape Version 1.2 or later browser.

Growth Staging of Wheat, Barley and Wild Oat

Original text authored by James E. Nelson 1/, Kenneth D. Kephart 2/, Armand Bauer 3/ and Jeffrey F. Connor 4/. HTML version created by Ken Kephart and Andrey P. Zarubin 5/. Original photography by Jayme Schlepp, MSU Photo Services, Montana State University, Bozeman, MT.
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  1. Former Assistant Professor of Weed Science, Dep.of Plant and Soil Sciences, Montana State University, Bozeman, MT.
  2. Former Assistant Professor of Crop Sciences, Dep. of Plant, Soil and Entomological Sciences, University of Idaho, Moscow, Idaho. Presently Superintendent, Southern Agricultural Research Center-Huntley, MT., University of Montana-Bozeman, MT.
  3. Former Soil Research Scientist (retired), USDA-ARS Northern Great Plains Research Lab, Mandan, ND.
  4. Former Graduate Research Assistant, Dep. of Plant and Soil Sciences, Montana State University, Bozeman, MT.
  5. Undergraduate student research assistant, University of Missouri, Columbia, MO.
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Contents
A Message To Growers

Profitable small grain production requires a thorough knowledge of crop development and growth, and how cultural and environmental factors can influence crop development. Crop and weed response to inputs such as fertilizers, pesticides, plant growth regulators and supplemental irrigation depend on the stage of development rather than on calendar date. Improper application timing may reduce chemical or fertilizer effectiveness, and, in some cases, result in crop injury and yield loss.

Proper application timing offers you an opportunity to achieve maximum wild oat control with postemergence herbicides. Frequently, producers and fieldmen do not take the time to properly determine the development stage of wild oat before selecting and applying a herbicide.

This publication will help you understand wheat, barley and wild oat development and growth. An easy-to-use staging procedure for cereal grains and wild oat is included. Standard development scales (Zadoks, Feekes, Haunt) and label recommendations for pesticide application timing can be applied to this staging method.

Special thanks is extended to American Cyanamid Company for assistance in the production of this publication and to manuscript reviewers for their contributions.

How to Select Plants

Use this method to stage both cereal grains and wild oat. Use an "M" or zig-zag pattern to select a crop and wild oat plant from 10 locations in each field (Fig. 1).

Use the Point Method to select each plant. Drop to one knee and immediately place your index finger on the ground (Fig. 2). Carefully remove the plant nearest your finger.

Refer to Figure 3, Figure 4, Figure 5 and Table 1 to help correctly identify the plant species. Identification may also be made by examining remnants of the attached seed. 


Table 1.  Identification characterisitcs for wheat, barley and wild oat.
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Characteristic      Wheat               Barley              Wild Oat
--------------------------------------------------------------------------------

ligule              membranous          membranous          membranous

auricles            short and hairy     long, clasping      absent
                    without hair

blades and collars  usually hairy       without hair        long hair on margins

sheaths             usually hairy       without hair        usually without hair

blade twist         clockwise           clockwise           counter-clockwise

--------------------------------------------------------------------------------
Field Staging Form

Identify the development stage of at least 10 plants each of the crop and wild oat and record them on one of the staging forms (see example, Fig. 6). The field development stage is the average of these plants. Record below the staging information for one plant per location in the field.

How to Handle Plants
Locate the first leaf (Fig. 7) 6/

The first leaf:

Position the plant.

Hold plant so that the first leaf points to your left and carefully fan-out the leaves and tillers. Follow this procedure for consistent results in staging.

Locate the main shoot or stem.

The main shoot or stem is usually the tallest and has the most leaves.
6/ Field-grown spring wheat (Triticum aestivum), barley (Hordeum vulgare)and wild oat (Avena fatua) were photographed in the studio. Wheat is used in dissected and close-up views.
How to Stage Plants

Count the leaves on the main shoot or stem.

Count the tillers.

Count the nodes. Has the flag leaf emerged? Has boot stage begun? Has head emergence and flowering occurred? Determine grain development stage.
Helpful Hints

All normal small grain plants follow the same general pattern of development. But the specific time interval between stages, the number of leaves and nodes on the main stem and number of tillers may very due to varieties, season, planting dates and locations.

For example :

Germination and Emergence

Under adequate growing conditions, the planted seed absorbs water and growth begins. Metabolic activity within the seed rises sharply when seed water concentration approaches 45 to 49 percent. A root called the radicle is the first plant part to emerge from the swollen seed (Fig. 8, Fig. 9). It elongates downward, anchors in the soil and absorbs water and nutrients. The radicle and four to five later-emerging lateral seminal roots comprise the primary root system. Following radicle emergence, the coleoptile emerges from the seed and elongates until the tip breaks the soil surface, where elongation is terminated in response to light. The coleoptile is a leaf sheath that encloses and protects the embryonic plant.

In wheat and barley, the coleoptile develops from the second or the third node on the plant. Since these nodes are normally located in the seed and their internodes do non elongate, the coleoptile originates from the level of seed. The internode between the coleoptilar node and the next higher node, often called the subcrown internode, has the ability to elongate and position the crown within one inch of the soil surface. At planting depths to one inch this internode will not elongate but at deeper planting depths it may elongate up to four inches if necessary (Fig. 10). At planting depths greater than three inches the next higher internode may also elongate (Fig. 11). A plant is judged completely emerged when 50 percent of the first leaf has emerged from the coleoptile and begins expanding above the soil surface.

Several nodes, separated by internodes that do not elongate, from the crown. Leaves, tillers and roots develop from the crown nodes. The node that bears the first leaf is designated node 1; the second leaf is node 2; and so on. The coleoptilar node is node 0 and the two nodes in the seed are designated negative numbers, such as -1,-2, etc. Crown depth is determined by variety, planting depth and the extent of internode elongation. The growing point is located at the crown until it is elevated by stem elongation.

Leaf and Tiller Development

A new leaf is counted when it is one-half the length of the leaf below it when using the Feekes of Zadoks scale. When using the Haun scale the development stage of the youngest leaf is based on its length relative to the length of the leaf below it (Fig. 12, Fig. 13, Fig. 14, Fig. 15, Fig. 16, Fig. 17, Fig. 18) 7/. Great care must be exercised when staging plants with more than five leaves because lower leaves die and are sloughed off the stem. Dead, dying or missing leaves must be counted. Look for leaf and sheath remnants at the crown.

A tiller may form a bud located at the coleoptilar node (coleoptilar tiller) and at each crown node (axillary tillers). The coleoptilar tiller can emerge at any time, independent of the number of leaves on the main stem. Axillary tillers usually begin to emerge when the plant has three leaves (Fig. 19). Rarely are more than five axillary tillers formed on a plant.

Tillers are identified numerically based on the leaf and node from which they arise. The coleoptilar tiller, tiller 0, emerges from the axil of the coleoptile; tiller one, from the first leaf axil and so on. Tiller leaves emerge from a sheath, called the prophyll, which can later be found enclosing the base of the tiller (Fig. 20). The prophyll can be used to identify tiller leaves from those on the main stem or other tillers.

Secondary tillers may arise from the prophyll node and leaf nodes of the primary tillers. In the same manner, tertiary tillers may occasionally be produced by secondary tillers. The primary tillers are usually the tallest of the tillers that emerge from a leaf axil. Leaves on primary tillers are positioned at right angles to the main stem leaves. When a plant is held by an observer with the fist main stem leaf on the left, the leaves on the primary tillers will be pointing toward and away from the observer. Leaves of secondary tillers will have a left-right orientation similar to those of the main stem and tertiary tiller leaves will be oriented toward and away from the observer like those of primary tillers.

Tillering capacity is a varietal trait and a physiological means of adapting to changing environmental conditions. More tillers may be produced when environmental conditions are favorable, plant populations are low, or soil fertility levels are high. Under stress, plants respond by producing fewer tillers or by aborting initiated tillers.

Tillers are counted as soon as they emerge above the soil surface or the leaf axil. The contribution of each tiller to final yield is directly related to the development stage achieved when reproductive development is initiated. Late developing tillers contribute little to overall yield. Tillers that emerge after the fifth main shoot leaf are likely to abort or not produce heads.

7/ Development stage scales: Z= Zadoks, F= Feekes, H= Haun

Adventitious Root Development

The adventitious or secondary root system is composed of roots that arise from the crown nodes of the main shoot and tillers. Two or more adventitious roots are generally formed at each crown node. Each tiller may produce its own adventitious root system as does the main stem, except that a single root instead of a pair is usually reduced at each node. The plant gradually becomes more dependent upon the adventitious root system as it develops to become the predominant root mass.

Generally, by flowering, the root system is fully established. The adventitious root system of spring wheat eventually becomes a profuse mass of fibrous roots, which may spread from six to nine inches on all sides of the plant and penetrate the soil to a depth of three to four feet. Winter grains and spring barley are generally deeper rooted than spring wheat. Degree of branching and depth of penetration depend upon variety, type and depth of soil, soil compaction, water, aeration and fertility level.

Wild Oat Development

Wild oat is ranked as the worst weed problem by wheat and barley producers in many western states. Wild oat infests more than 28 million acres of small grain in the United States resulting in an estimated annual yield loss and prediction cost of $304 million (WSSA Wild Oat Situation Report-1976.). Wheat and barley yields are sharply affected by wild oat infestations. Ten wild oat plants per square feet can reduce spring barley grain yield by 10 to 30 percent, depending on production practices and environmental conditions. Winter wheat usually is more competitive against wild oat than spring barley. Spring wheat is less competitive against wild oat compared to spring barley.

Wild oat develop in a similar manner to wheat and barley (Fig. 21, Fig. 22, Fig. 23, Fig. 24, Fig. 25) with the exception of the positioning of the coleoptilar node during seedling emergence. In wild oat, the internode below the coleoptilar node elongates to elevate the shoot to within one inch of the soil surface where the crown will form (Fig. 26, Fig. 27). The coleoptilar node is the lowest-positioned crown node.

Wild Oat Development Stage Scales For Timing Postemergence Pesticides

Wild oat susceptibility to post-emergence herbicides is influenced by development stage. Tillers begin to emerge during the application time period for most wild oat herbicides. The wild oat stage scales presented on product labels do not distinguish between leaves and tillers which confuses product selection and application timing decisions. To determine the proper time to apply the herbicide, some product labels count tillers as leaves while other labels count only leaves and do not consider tillers. Example of these two wild oat staging methods are provided below.

Method 1: For herbicides (ASSERT (r) 8/, Hoelon (r) 9/) recommended for use on one- to four-leaf wild oat plants: Tillers are counted as leaves.

Method 2: For herbicides (AVENGE (r) 8/) recommended for use on three- to five leaf stage wild oats: Only leaves are counted.

Example 1. A three-leaf wild oat with one tiller.

Example 2. A four-leaf wild oat with one tiller. Example 3. A five-leaf wild oat with two tillers.

8/ Trademark, American Cyanamid Company, (c) 1988.
9/ Trademark, Hoechst-Roussel Agri-Vet Company.

Head Initiation

Plant interactions with temperature and day length prompt the transition from vegetative to reproductive stages. Reproductive development of true winter varieties is initiated by vernalization during exposure to cool temperatures for a required length of time. Temperatures between 32 and 50F induce cold hardening and satisfy vernalization requirements. The required period of low temperature exposure varies with variety and decreases with lower temperatures and advancing plant development. In addition to vernalization, exposure to progressively longer day length periods is necessary to initiate reproductive development. Spring varieties do not possess an absolute vernalization requirement. Reproductive development in most spring varieties is triggered by light and accumulative heat units (growing degree days).

The head or spike is initiated on each tiller during the fourth-leaf stage and before stem elongation begins. The maximum number of kernels that may mature on each head is determined by the number of florets that are initiated. Florets are first initiated in the middle portion of the microscopic head and then outward toward the ends (Fig. 28). Stress conditions may cause florets to abort in the reverse order in which they were initiated, resulting in empty or sterile florets at the ends of the head. Once head formation is complete, stem elongation elevates the terminal growing point of each tiller upwards within the leaf sheaths.

Stem Elongation

Stem elongation or jointing occurs as a result of internode elongation. Usually a plant has about five to six leaves on the main shoot when internode elongation first begins (Fig. 29, Fig. 30, Fig. 31, Fig. 32). Throughout development, the lower four nodes remain in the crown. The fifth node may remain in the crown or be elevated slightly and nodes six and seven are generally elevated above the soil. The elongating internode is hallow between the crown and the elevated growing point, except in solid stem varieties. Rapid stem or internode elongation brings the developing head above the soil surface. Each elongation internode becomes progressively longer and eventually leads to head emergence.

Stems can be split with a knife to determine if a plant is in early stem elongation stage (Fig. 33). As the internodes elongate, the nodes become visually detectable on the stem and are easily counted (Fig. 34). The mature stem of most wheat and barley varieties has form three to four visible nodes.

The peduncle, the last elongated internode which supports the head, accounts for a good proportion of the overall stem length. Height is genetically determined but is subject to environmental influence. Certain growth regulators reduce plant height and increase lodging resistance. Their application is timed to inhibit peduncle elongation.

The period of rapid head growth in which individual florets become ready for pollination and fertilization, parallels stem elongation (Fig. 35). Tiller development is in synchronization with the main stem so that tillers flower soon after the main stem.

Flag Leaf

The flag leaf is the last leaf to emerge before the head. It begins to emerge just after the third above-ground node is observed of most varieties (Fig. 36, Fig. 37). The flag leaf contributes 75 percent or more of the photosynthate needed for maximum grain yield. Flag leaf emergence is a visual indicator that the plant will soon be in the boot stage.

Boot Swollen

Following flag leaf development, the flag leaf sheath and the peduncle elongate and the developing head is pushed up through the flag leaf sheath. The leaf sheath swells to form the boot as the head continues to develop (Fig. 38). The boot stage is complete when the awns (or the head in awnless varieties) become visible at the flag leaf collar and the sheath is forced open by the developing head.

Head Emergence and Flowering

Heading occurs as the peduncle continues elongation and pushes the head out of the flag leaf collar (Fig. 39, Fig. 40, Fig. 41). Flowering (pollination) may occur either before or after head emergence depending on plant species and variety. Pollen formation and pollination are very sensitive to environmental conditions.

Cereals are classified as either open-flowering or closed-flowering types. Flowering usually occurs in closed-flowering varieties prior to head emergence and in open-flowering varieties shortly after head emergence. Many winter barley varieties are open-flowering whereas spring barley varieties are usually closed-flowering. Most varieties of wheat are of the open-flowering type.

Flowering in open varieties is usually observed by anther extraction from each floret, although this may not occur under stress conditions. In closed-flowering types, the anthers remain inside each floret. If the anthers within a floret are yellow or gray, rather than green, it is reasonably certain that flowering has occurred (Fig. 42, Fig. 43).

Generally, flowering in wheat begins within three or four days after head emergence, while flowering in barley usually occurs just before or during head emergence. Flowering begins from about the middle section of the main stem head and progress to the top and bottom of the head. All heads of a plant flower within a few days. Within a few hours of pollination, the embryo and endosperm begin to form.

Grain Development Stages
Watery Ripe Stage

During the watery ripe stage, kernel length and width are established and the kernel rapidly increases in size, but does not accumulate much dry matter (Fig. 44, Fig. 45). A clear fluid can be squeezed from the developing kernel. The plant is green, but the lower leaves begin to die.

Milk Stage

During the milk stage a white, milk like-fluid can be squeezed from the developing kernel (Fig. 46, Fig. 47). By the end of milk stage the embryo is fully formed and about 1/32 inch in length. During the course of this stage, nutrients stored in lower leaves are redistributed to the upper plant, including the developing kernels, causing several of the bottom leaves to die.

Soft Dough Stage

The water concentration of the kernel has decreased to the point where the material pressed out of the kernel is no longer a liquid but has the consistency of meal or dough (Fig. 48, Fig. 49, Fig. 50, Fig. 51). The kernel rapidly accumulates starch and nutrients and by the end of this stage the green color begins to fade. Most of the kernel dry weight is accumulated in this stage. In barley, the palea and lemma become firmly adhered to the kernel. Once kernel water concentration decreases to about 75 percent, swathing of spring wheat can begin without reducing yield, test weight, or protein level.

Hard dough stage

The kernel reaches physiological maturity at the end of this stage (Fig. 52, Fig. 53). At physiological maturity, the glumes and peduncle are no longer green and little green coloring remains in the plant. Kernel water concentration decreases from a level of 40 to 30 percent. The main reductions in yield beyond this stage result from harvest losses, and environmental injuries, such as hail and sprouting.

Kernel Hard Stage

The plant has become completely yellow and the kernel has become firm (Fig. 54, Fig. 55). The kernel is difficult to physically divide by thumbnail but the surface of the grain can be dented with the edge of the thumbnail. Kernel water concentration is 20 to 25 percent. Unless drying facilities are available, the crop must be swathed and windowed at this stage because the grain water concentration is too high for safe storage.

Harvest Ripe Storage

The plant has become dry and brittle and the kernel is hard (Fig. 56, Fig. 57, Fig. 58). The kernel cannot be crushed between thumbnails and is difficult to dent its surface with the edge of the thumbnail. If the kernel is crushed by other means, it fragments. When the kernel water concentration has decreased to 13 to 14 percent the grain is ready for direct combining and storage.

Dry Matter Accumulation

Dry matter accumulation in the aerial parts of wheat and barley change with plant development stage (Fig. 59). From emergence to about the two-leaf stage, all of the aerial dry matter is in leaves. From that stage forward, dry matter begins accumulating rapidly in the stems. The developing head, which is initiated at about the four-leaf stage, is regarded as part of the stem until heading. By the flag-leaf stage about 30 percent of the total aerial dry matter is accumulated and it is almost equally distributed between leaves and stems. About 55 percent of the total aerial dry matter is accumulated by the time the heads are completely emerged. Dry matter accumulation in the stems declines after heading and all additional dry matter is accumulated in the kernels. By kernel hard stage dry matter is distributed essentially between stems and heads.

Cereal Grain Development Scales

The development and growth of cereal grains have been translated into several numeric scales to quantify development for scientific and management purposes. Industry is now adopting these staging scales as a means of properly identifying application times for certain products. The most commonly used scales are the Feekes, Zadoks and Haun.

The Feekes scale is probably the best known and most widely used numerical staging scale. Eleven development stages describe physical plant changes from the first-leaf stage through grain ripening (Fig. 60 and Table 2). For example, a six-leaf plant with one node would be stage 6. The heading and ripening stages are subdivided for greater detail. 


Table 2.  Cereal grain development stages by Zadoks, Feekes and Haun.
------------------------------------------------------------------------
   Zadoks   Feekes     Haun**
   Scale    Scale      Scale       Description
------------------------------------------------------------------------
                                   Germination
    00        -         -          Dry Seed
    01        -         -          Start of imbibition
    03        -         -          Imbibition complete
    05        -         -          Radicle emerged from seed
    07        -         -          Coleoptile emerged from seed
    09        -        0.0         Leaf just at coleoptile tip

                                   Seedling Growth
    10        1         -          First leaf through coleoptile
    11        -        1.0         First leaf extended
    12        -        1.+         Second leaf extending
    13        -        2.+         Third leaf extending
    14        -        3.+         Fourth leaf extending
    15        -        4.+         Fifth leaf extending
    16        -        5.+         Sixth leaf extending
    17        -        6.+         Seventh leaf extending
    18        -        7.+         Eighth leaf extending
    19        -         -          Nine or more leaves extended

                                   Tillering
    20        -         -          Main shoot only
    21        2         -          Main shoot and one tiller
    22        -         -          Main shoot and two tillers
    23        -         -          Main shoot and three tillers
    24        -         -          Main shoot and four tillers
    25        -         -          Main shoot and five tillers
    26        3         -          Main shoot and six tillers
    27        -         -          Main shoot and seven tillers
    28        -         -          Main shoot and eight tillers
    29        -         -          Main shoot and nine tillers

                                   Stem Elongation
    30       4-5        -          Psuedo stem erection
    31        6         -          First node detectable
    32        7         -          Second node detectable
    33        -         -          Third node detectable
    34        -         -          Fourth node detectable
    35        -         -          Fifth node detectable
    36        -         -          Sixth node detectable
    37        8         -          Flag leaf just visible
    39        9         -          Flag leaf ligule/collar just
                                   visible

                                   Booting
    40        -         -          ---
    41        -        8-9         Flag leaf sheath extending
    45        10       9.2         Boot just swollen
    47        -         -          Flag leaf sheath opening
    49        -        10.1        First awns visible

                                   Inflorescence Emergence
    50       10.1      10.2        First spikelet of inflorescence
                                   visible
    53       10.2       -          1/4 of inflorescence emerged
    55       10.3      10.5        1/2 of inflorescence emerged
    57       10.4      10.7        3/4 of inflorescence emerged
    59       10.5      11.0        Emergence of inflorescence
                                   completed

                                   Anthesis
    60      10.51      11.4        Beginning of anthesis
    65        -        11.5        Anthesis 1/2 completed
    69        -        11.6        Anthesis completed

                                   Milk Development
    70        -         -          ---
    71      10.54      12.1        Kernel watery-ripe
    73        -        13.0        Early milk
    75       11.1       -          Medium milk
    77        -         -          Late milk

                                   Dough Development
    80        -         -          ---
    83        -        14.0        Early dough
    85       11.2       -          Soft dough
    87        -        15.0        Hard dough

                                   Ripening
    90        -         -          ---
    91       11.3       -          Kernel hard (difficult to
                                   divide by thumbnail)
    92       11.4      16.0        Kernel hard (can no longer
                                   be dented by thumbnail)
    93        -         -          Kernel loosening in daytime
    94        -         -          Overripe, straw dead and collapsing
    95        -         -          Seed dormant
    96        -         -          Viable seed giving 50% germination
    97        -         -          Seed not dormant
    98        -         -          Secondary dormancy induced
    99        -         -          Secondary dormancy lost

------------------------------------------------------------------------
** The Haun scale stages used in this example from boot through ripening
are based on a seven-leaf plant.

The Zadoks scale provides more detailed information during early development stages than the Feekes scale. The scale is base on ten principal plant development stages, which are divided into secondary stages. A new leaf is counted as fully emerged when 50 percent of the leaf blade has unfolded. Two or more codes may be used to describe a plant using the Zadoks scale. For example, wheat that has six leaves unfolded (16), three tillers (23) and one node on the main stem (31) would be staged as 16, 23, 31.

The Haun scale provides an accurate description of plant development from the appearance of the first leaf through flowering. However, tiller and grain development are not described. A number, called a growth unit, is assigned to each leaf as it develops, and to flag leaf sheath elongation, booting, heading and peduncle elongation. Each growth unit is subdivided into decimal fractions which begin with its own appearance and end with the appearance of the next growth unit. For example, a wheat plant that has five fully elongated leaves and an elongating sixth leaf that measures 60 percent of the length of the fifth leaf is staged 5.6.

Glossary of Terms

Adventitious roots - Roots produced by crown nodes on the main shoot and tillers.

Anther - The reproductive portion of a flower which produces and releases the pollen.

Anthesis - The time of flowering or pollination.

Auricles - A pair of claw-like projections at the junction of the sheath and blade.

Axillary tillers - The tillers that emerge from the leaf axils.

Blade - The flat expanded portion of a leaf.

Coleoptile - The leaf sheath which surrounds and protects the embryonic plant as it emerges from the seed.

Coleoptilar tiller - The tiller that emerges from the coleoptilar node.

Collar - The junction of the leaf blade and leaf sheath.

Crown - Several nodes whose internodes do not elongate.

Endosperm - The area of starch and protein storage in the kernel.

Floret - The flower contained in the spikelet.

Glumes - The husk of the spikelet.

Growing point - The plant part where differentiation of leaves, tillers and the head occurs.

Internode - The region between two successive nodes.

Leaf axil - The junction of the leaf with the main stem.

Lemma - The outer, lower bract enclosing the flower in a spikelet.

Ligule - A short membrane or row of hairs of the inside of the leaf at the junction of the blade and sheath.

Nodes - The area of active cell division from which leaves, tillers and adventitious roots arise.

Palea - The inner, upper bract enclosing the flower in a spikelet.

Peduncle - The last elongated internode which supports the head.

Photosynthate - The products of photosynthesis.

Plant Growth Regulator - A chemical used to inhibit peduncle elongation and increase lodging resistance.

Pollen - The powder-like matter produced by the anthers which functions as the male element in pollination.

Pollination - Fertilization of the embryo by pollen.

Primary tiller - A tiller produced by a node on the main stem.

Prophyll - The sheath which encloses the base of a tiller.

Radicle - The first root to emerge from the seed .

Secondary tiller - A tiller produced by a primary tiller.

Seminal roots - The roots originating from the seed.

Sheath - The tubular portion of a grass leaf that encloses the stem.

Spikelet - Subdivision of the head.

Subcrown Internode - The internode between the coleoptilar node and the next higher node which elongates to position the crown within one inch of the soil surface in wheat and barley.

Tertiary tiller - A tiller produced by a secondary tiller.

Tiller - A shoot that arises from buds at the base of a plant.

Vernalization - Plants must be subjected to low temperatures for a period of time before they enter the reproductive stages of development.

References

Anderson, P. M., E. A. Oelke and S. R. Simmons. 1985. GROWTH AND DEVELOPMENT GUIDE FOR SPRING BARLEY. University of Minnesota Agricultural Extension Folder AG-FO-2548.

Bauer, A., C. Fanning, J. W. Enz and C. V. Eberlein. 1994. USE OF THE GROWING-DEGREE DAYS TO DETERMINE SPRING WHEAT GROWTH STAGES. North Dakota Coop. Ext. Ser. EB-37. Fargo, N.D.

Bauer, A., A. B. Frank and A. L. Black. 1984. ESTIMATION OF SPRING WHEAT LEAF GROWTH RATES AND ANTHESIS FROM AIR TEMPERATURE. Agron. J. 76:829-835.

Bauer, A., A. B. Frank and A. L. Black. 1987. AERIAL PARTS OF HARD RED SPRING WHEAT. I. DRY MATTER DISTRIBUTION BY PLANT DEVELOPMENT STAGE. Agron. J. 79:845-852.

Bauer, A., D. Smika and A. Black. 1983. CORRELATION OF FIVE WHEAT GROWTH STAGE SCALES USED IN THE GREAT PLAINS. AAT-NC-7. Agricultural Research Service USDA.

Briggs, D. E. 1978. BARLEY. Chapman & Hall, London.

Dyer, W., P. Fay, P. Rardon and V. Stewart . 1983. THE WILD OAT STAGING CARD. Montana Agricultural Experiment Station Capsule Information Series Number 30.

Haun, J. R. 1973. VISUAL QUANTIFICATION OF WHEAT DEVELOPMENT. Agron. J.65:116-119.

Klepper, B.,R. W. Rickman and C. M. Peterson. 1982. QUANTITATIVE CHARACTERIZATION OF VEGETATIVE DEVELOPMENT OF SMALL CEREAL GRAINS. Agron. J. 74:789-792.

Klepper, B., R. W. Rickman and R. K. Belford. 1983. LEAF AND TILLER IDENTIFICATION ON WHEAT PLANTS. Crop Sci. 23:1002-1004.

Large, E. B. 1954. GROWTH STAGES IN CEREALS. ILLUSTRATIONS OF THE FEEKES SCALE. Plant Pathol. 3:128-129.

Peterson, C. M., B. Klepper and R. W. Rickman. 1982. TILLER DEVELOPMENT AT THE COLEOPTILAR NODE IN WINTER WHEAT. Agron. J. 74:781-784.

Quisenberry, K. S. (Ed.) 1967. WHEAT AND WHEAT IMPROVEMENT. American Society of Agronomy, Inc., Madison, Wisc.

Simmons, S. R., E. A.Oelke and P. M. Anderson. 1985. GROWTH AND DEVELOPMENT GUIDE FOR SPRING WHEAT. University of Minnesota Agricultural Extension Folder AG-FO-2547.

Stoskopf, N. C. 1985. CEREAL GRAIN CROPS. Reston Publishing Company. Inc., Reston, Virginia.

Waldren, R. P., and A. D. Flowerday. 1979. GROWTH STAGES AND DISTRIBUTION OF DRY MATTER, N, P, AND K IN WINTER WHEAT. Agron. J. 71:391-397.

Zadoks, J. C., T. T. Chang and B. F. Konzak. 1974. A DECIMAL CODE FOR THE GROWTH STAGES OF CEREALS. Weed Res. 14:415-421.

Funding and Distribution

Funding to facilitate production of the original publication was provided by the American Cyanamid Company, Wayne, NJ. Distribution of Montana State University Miscellaneous Bulletin 4387 and University of Idaho Miscellaneous Series 118 was in furtherance of the Acts of the Congress of May 8, and June 30, 1914, by the Extension Services of Montana State University, James R. Welsh, Director, and of the University or Idaho, H.R. Guenthner, Director. The programs of the Montana State University Extension Service, the University of Idaho Extension Service and the University of Missouri-Columbia are available to all people regardless of race, creed, color, sex, handicap or national origin.

Acknowledgements

The original publication contained several errors and omissions. I would like to personally thank Drs. Glen A. Murray and Donn C. Thill, Dep. of Plant, Soil and Entomological Sciences, University of Idaho, for reviewing the original version and suggesting many changes that were incorporated into this World Wide Web edition. I also wish to thank Dr. Bill McFarland, Extension Technology and Computer Services - University of Missouri, for providing access to the ETCS server at the University of Missouri where this web document is currently posted.
Ken Kephart