Specific Work Instructions: Pedigreed Cereal Seed Crop Inspection Procedures

This page is part of the Guidance Document Repository (GDR).

Looking for related documents?
Search for related documents in the Guidance Document Repository

SWI 142.1.2-2

Table of Contents

Date

This version of Seed Program Specific Work Instruction (SWI) 142.1.2-2 Pedigreed Cereal Seed Crop Inspection Procedures was issued April 1, 2015.

Contact

The contact for this Seed Program Specific Work Instruction (SWI) is the National Manager, Seed Section. Comments regarding the content of this document should be addressed to the National Manager at SeedSemence@inspection.gc.ca.

Review

This Seed Program SWI is subject to periodic review. Amendments will be issued to ensure the SWI continues to meet current needs.

Endorsement

This Seed Program SWI is hereby approved.

space
Director, Plant Production Division

space
Date

Distribution

This document will be maintained on the CFIA website. The National Manager, Seed Section will maintain the signed original. A copy of the latest version is available upon request to SeedSemence@inspection.gc.ca.

0.0 Introduction

The purpose of pedigreed seed crop inspection is to provide an unbiased inspection and complete a Report of Seed Crop Inspection for submission to the Canadian Seed Growers' Association (CSGA) on the isolation, condition, and purity of the seed crop. It is the inspector's responsibility to describe the seed crop and its surroundings as observed at the time of inspection.

1.0 Scope

This Seed Program SWI outlines the procedures that a seed crop inspector will follow when inspecting pedigreed status seed crops of wheat, barley, oats, triticale, and rye. These seed crop inspection procedures provide the CSGA with confidence that production has been measured against the requirements for seed crop varietal purity and seed crop production standards as specified by the CSGA's Canadian Regulations and Procedures for Pedigreed Seed Crop Production (Circular 6).

2.0 References

The publications referred to in the development of this SWI are those identified in Seed Program Regulatory Authority (SPRA) 101 - Definitions, Acronyms, and References for the Seed Program.

In addition the following were used:

3.0 Definitions

For the purposes of this SWI, the definitions given in SPRA 101 and the following apply:

Aleurone
granular protein in the outermost layer of the endosperm of many seeds or cereal grains; colour variation of the aleurone layer is used to distinguish barley varieties
Anthesis
the flowering stage when the anthers burst, pollen is shed and the stigma is ready to receive the dispersed pollen
Anthocyanin
plant pigment ranging from red to violet to blue
Awns
conspicuous prolongations of the glumes or lemmas
Chaff
fragments of straw including the glume and hull removed from cereal grains in threshing or processing
Fatuoid
a common mutant found in oat crops; may be called a 'false wild oat'; usually has heavier protruding black awns distinguishable at maturity
Floret
the stamens, pistils and lodiculae enclosed by the lemma and palea
Glabrous
having no projections or pubescence
Glume
two bracts found at the base of a grass or cereal spikelet
Hull
the outer covering of a seed made up of the lemma and palea which may be removed freely as in wheat, or adhere as in hulled barley
Hulless
a seed which has no outer covering or has an outer covering which is easily removed
Inflorescence
the head of cereal crops consisting of flowers grouped on the rachis, the central axis
Lemma
the lower or dorsal bract of the spikelet enclosing the seed; in wheat, it is readily removed with threshing, but may adhere in hulled barley and oats
Lodiculae
small scales at the base of the ovary in a grass flower; believed to be a rudimentary perianth
Monoecious
having male and female reproductive organs borne on a single plant
Nodes
the point on a stem from which leaves, shoots, or flowers grow
Palea
the upper bract that, with the lemma, forms two bracts that enclose the grass floret
Panicle
the inflorescence of oats consisting of a main stem with branches and sub-branches arising from a central axis
Pollination
the process by which pollen is transferred from the anther (male part of a flower) to the stigmatic surface of the pistil (female part of a flower)
Rachilla
the axis of the spikelet that bears the florets
Rachis
an extension of the stem on which the spikelets are found
Speltoid
common mutants in wheat crops; can appear in a number of different forms, the most common and readily visible being the "tall late" which is taller and later than normal for the variety; the heads are longer and thinner with a distinct taper from base to tip; glumes are strongly keeled with a square shoulder and generally are stiff and cannot be bent away from the spikelet without breaking; speltoids tend to be self-eliminating because they are late maturing, hard to thresh, small seeded and often have low fertility
Supernumerary Spikelets
spikelets arising from the nodes below and at right angles to the normal spikelets; produced in a large proportion of certain wheat and triticale varieties; vary in size and development; in varieties which produce many supernumerary spikelets, the ears look ragged or untidy because the supernumerary spikelets arise at random up the length of the ear disturbing the normal neat alternate arrangement of spikelets

4.0 Specific Inspection Procedures

Inspection of pedigreed seed crops of cereals should be conducted in accordance with the instructions in Quality Systems Procedure (QSP) 142.1 - Pedigreed Seed Crop Inspection and SWI 142.1.1 - Pedigreed Seed Crop Inspection, as well as the instructions provided in this SWI.

The following procedures apply in general to inspection of pedigreed seed crops of cereals. Specific conditions or requirements for different crop types are addressed in crop-specific sections of this document.

4.1 Inspection Requirements

Each crop will require one inspection performed between the time of heading through to maturity. It is recommended to inspect cereal crops after anthesis (flowering), and after the glumes and awns are mature enough to show colour if this is a characteristic of the variety (such as in Durum wheat and barley). Oats are best inspected when the plants are still green as it is easier to distinguish differences in the colour and waxiness of the plants. However, when oats are ripe, it is easier to identify fatuoid oats since the top florets shell out and the empty glumes are most visible. In all cases, the inspection should not be left so late in the season that the plant parts (leaves, stems, heads, awns) are degraded to the point that the characteristics cannot be easily observed.

For most self-pollinated cereal crops an isolation distance of 3 m is sufficient, however, for rye and buckwheat, the isolation is 300 m from different varieties or non-pedigreed crops of rye (or buckwheat). When inspecting rye or buckwheat, the seed crop inspector should include a comment in the isolation section of the Report of Seed Crop Inspection to indicate 'No other rye (or buckwheat) within 300 meters' when this is the case.

Seed crop inspectors should refer to Circular 6 for details on isolation requirements, previous land use and other requirements for inspection of specific crop kinds.

The seed crop inspector should refer to Appendices II to VII for general descriptions of cereal species to assist in varietal identification.

4.2 Crop Inspection of Plant Pest Tolerance Management Varietal Blends

Pedigreed seed of pest tolerant wheat varieties is sold as a component in a varietal blend with seed of a small proportion of a susceptible variety (refuge variety) in order to prolong the utility of the tolerance trait. In cases where the pests do not travel very far beyond their emergence site, the refuge variety is planted interspersed with the pest tolerant variety rather than as a border or in a block.

If pest tolerant varieties are planted in monocultures, the selection pressure in the pest population for mutations to overcome the tolerance trait is increased. In most cases, 5% to 15% of the varietal blend must be made up of the susceptible variety in order to provide an effective refuge. Seed crop inspectors are not expected to verify the relative proportions of tolerant and susceptible varieties in the inspected crop.

Seed crop inspectors must refer to the DoVs for both varieties in the varietal blend. When encountering plants that do not conform to the DoV, seed crop inspectors must determine whether the deviant plant is a plant of the interspersed susceptible variety, a described variant of either the tolerant or susceptible variety or an off-type. The seed crop inspector must provide as much detail as possible on how the deviant plants differ from the norm of the variety(s). An official seed tag or a picture of the tag must be attached to the Report of Seed Crop Inspection.

4.3 Completing the Report of Seed Crop Inspection

In addition to the general instructions provided in SWI 142.1.1 Pedigreed Seed Crop Inspection, the following are key factors in completing the Report of Seed Crop Inspection for specific cereal crops

Rye

As rye is an open-pollinated crop, particular attention must be paid during inspection to the neighbouring crop. On the Report of Seed Crop Inspection, the inspector must complete the section on open pollinated crops. This requires stating the variety of, the distance to, and the pedigreed status (if any) of other crops of the same kind adjacent to the crop. If a portion of the inspected crop is removed in lieu of an isolation the inspector must state the distance that has been removed.

Barley

If true loose smut is observed in a barley crop, it is to be documented in the Report of Seed Crop Inspection in the "Disease" field of the "Condition of Crop" section. In addition, the location of the disease in the field and the approximate area (percentage) of the crop that is infected must be described in the "Comments" section of the Report of seed crop inspection.

Oats

When fatuoids, false wild oats or wild oats are observed in a crop of oats, they are to be included in counts. Wild oats are reported as Weeds Difficult to Separate. Fatuoids and false wild oats are reported as off-types.

Wheat

It should be noted that the crop standards for Canadian Prairie Spring (CPS) wheat allow for higher levels of off-types and other varieties in crops producing Registered and Certified status seed than those of other wheat classes (Select, Foundation). The seed crop inspector should refer to Circular 6 for further information before completing the "Off-types and other varieties" section of the Report of Seed Crop Inspection. If speltoids are observed, they are to be reported as off-types.

4.4 Previous Land Use

The seed crop inspector should refer to Circular 6 to determine the conditions for the production of a pedigreed seed crop on land previously planted to similar crops.

Appendices

Appendix I: Common Morphological Synonyms

  • Awn - Beard
  • Chaff - Glume
  • Culm - Straw - Stem
  • Glabrous - Bald
  • Glaucosity - Waxiness
  • Head - Spike - Ear - Inflorescence - Flower
  • Lemma - lower bract
  • Node - Joint
  • Palea - upper bract
  • Pubescent - Hairy

Appendix II: Descriptions of Cereal Species

The following section outlines the characteristics displayed at the time of inspection for cereal species commonly grown for pedigreed status seed.

The seed crop is inspected for varietal purity and varietal identity based on a comparison with the descriptions of specific morphological characteristics provided in the DoV for the variety.

The following table lists common visual morphological characteristics of multiple cereal species that are useful in inspecting pedigreed status seed crops of cereals. Other characteristics which are unique to a single cereal species are outlined in Appendices III to VII.

Cereal Crop Specific Visual Morphological Characteristics
Species Characteristic Characteristic Description
Wheat, Triticale Straw pith Cut the straw cleanly at a mid-point between the ear and the upper stem node. The thickness of the wall of the stem depends on the amount of soft tissue beneath the hard epidermis and is classified as either hollow, thick-walled or solid. This characteristic must not be regarded as definitive as variations occur as a result of different environmental and climatic conditions. In sawfly resistant varieties, the pith is always solid or very thick-walled as a defence mechanism against the sawfly. (See Appendix III Wheat)
Wheat, Barley, Triticale, Rye Head attitude (at maturity) Head attitudes range from: erect (upright up to 30° angle from vertical), semi-erect, inclined (30° to 90°), horizontal, semi-nodding, nodding (greater than 90°).
Wheat, Barley, Triticale, Rye Head shape The head shape is often determined by the density of the grains. A very dense grain arrangement on a short head usually results in a triangular shaped head. Head shapes include: tapering, parallel, oblong, clavate and fusiform. (See Appendix III Wheat)
Wheat, Rye, Triticale Head density Head density is determined by the relative length of the rachis segments, and ranging from lax to dense. Varieties with visible spaces between grains when viewed from the side as a result of long rachis segments within the head are described as lax. (See Appendix IV Barley)
Oats, Barley Hulledness Hulled oats and barleys have strong glumes which hold the seed in the spikelets, whereas varieties of hulless oats and barley are essentially 'naked' and the seeds are released easily from the lemma and palea.
Wheat, Barley, Triticale Glume pubescence Glumes of certain uncommon varieties are covered with a mat of fine hairs which resemble felt or fine fur. Glume pubescence is a very distinct character that is classified as glabrous, slightly pubescent, or strongly pubescent. (See Appendix III Wheat)
Wheat, Barley, Triticale Awn length The actual length of the awns as they extend beyond the head can vary greatly from extending longer than the length of the head itself to extending less than the length of the head. (See Appendix IV Barley)
Wheat, Barley, Triticale, Oat Waxiness (head and culm) Many varieties have a coating of wax on leaves, stems and other surfaces. 'Non-waxy' surfaces actually have a glossy or wax-finished appearance whereas 'waxy' surfaces have a thin deposit of dull waxy powder which is white, pale-grey or light blue in colour. Flag leaves and spikes without a waxy surface appear 'yellow-green' instead of 'blue-green'. The best places to find a potentially waxy surface are the base of the ventral sides of the lemma, the lower part of the palea, or the stem. The location of wax may be influenced by the environment.

Appendix III: Wheat (Triticum spp.) Description and Illustrations

Wheat is a monoecious plant with perfect flowers (both male and female reproductive parts in the same flower). It reproduces sexually as a self-pollinated crop. Cross pollination occurs at usually less than 3%, however may be as high as 10% in some genotypes and/or environments. The inflorescence of wheat is a determinate composite spike (head). Spikelets are alternately arranged on the rachis. Each spikelet has two bract-like empty glumes that enclose two to nine florets. The outer parts of each floret consist of a lemma and a palea.

Three types of wheat exist; spring wheat, winter wheat and durum wheat. Winter wheat is the same species as spring wheat (Triticum aestivum) and shares the same identification characters. Winter wheat differs from spring wheat in that it has a winter habit, requiring vernalization, wherein the exposure to cool temperatures and short day initiates reproduction. Winter wheat is planted in the late summer, overwintering as an herbaceous plant, and then flowers and sets seed the following summer, earlier than spring planted varieties of spring wheat.

Durum wheat (Triticum turgidum spp. durum) is a separate species from spring and winter wheats. The head and neck of durum wheat are more compact than those of common wheat and appear squarish in cross section. Durum wheat is always awned. Different varieties of durum can sometimes be distinguished by their awn colour (black or white) which is expressed as the plants near maturity. The awn colour may be affected by frost (bleaches out the colour) or other environmental influences.

For inspection purposes, wheat can be grouped into two groups. Those possessing awns greater than 5 cm in length up to the length of the head (bearded), and beardless, whose awns are either absent or very short in comparison. Similarly awnless, apically awnletted and awnletted are used to describe awn characteristics. In most of the awnless varieties, the length of the lemma awns increases towards the apex of the head, and in certain varieties, the length of the awns may justify the description of semi-bearded.

The seed crop inspector, inspecting seed crops of cereal species should be familiar with einkorn, emmer and spelt species which are precursors to modern cereals. Einkorn along with emmer and spelt are often referred to as 'the covered wheats', since the kernels do not thresh free of the lemma, palea, and glume upon harvesting. Small quantities of these crop kinds are certified in Canada, therefore there is the potential that they may be present as impurities during crop inspection. See Appendix III.

Care should be taken when a wheat plant with a bleached white head is discovered as this may not be an off-type. Bleached white heads are most commonly caused by Fusarium, but may also be caused by diseases such as take-all, eyespot, or cephalosporium stripe, by insects such as sawfly, or stem maggots, by environmental conditions or herbicide exposure. For more information, see CropPest Ontario, volume 16, issue 6 (June 17th, 2011).

Wheat plant characteristics after heading

The following characteristics are to be considered for observations of varietal purity and identity during inspection of seed crops of wheat.

  • Glume Characteristics: Variations will be encountered within a variety and also over the length of the ear
  • Glume internal imprint: These clearly marked areas are caused by the pressure of the external surface of the lemma. This area can be seen as dark shadowy areas between the veins or nerves which run from the base of the glume to the beak and shoulder margins and are classified as absent, small, medium, or large

Other traits to consider when inspecting wheat varieties

  • Awn attitude
  • Awn colour
  • Awn length
  • Culm neck shape
  • Glume beak shape and length
  • Glume colour
  • Glume length
  • Glume shoulder shape and width
  • Glume pubescence
  • Glume width
  • Head attitude
  • Head awnedness
  • Head density
  • Head length (excluding awns, use first tiller)
  • Head shape
  • Head waxiness
  • Height (stem plus spike, excluding awns)
  • Pubescence on upper culm internode
  • Rachis margin pubescence
  • Straw pith thickness
  • Supernumerary spikelets
  • Upper culm internode waxiness

Wheat Diagrams

Wheat Straw Pith Thickness (in cross section of the straw at middle of internode below the neck)

Diagram of wheat straw pith thickness. Description follows.
Description for photo - Description of diagram of wheat straw pith thickness

Straw Pith thicknesses (in cross section at middle of internode below the neck) - Hollow, Thick-walled (with a thick layer of pith), and Solid (filled, or nearly filled with pith).

Wheat Spike Density

Diagram of wheat spike density. Description follows.
Description for photo - Description of diagram of wheat spike density

This diagram shows three types of Spike Density - Lax, Medium, and Dense.

Wheat Spike Awnedness

Diagram of wheat spike awnedness. Description follows.
Description for photo - Description of diagram of wheat spike awnedness

This diagram shows four types of wheat Spike Awnedness - Awnless, Apically-awnletted, Awnletted, and Awned.

Wheat Spike Shape

Diagram of wheat spike shape. Description follows.
Description for photo - Description of diagram of wheat spike shape

This diagram shows four types of wheat Spike Awnedness - This diagram shows four wheat spike shapes - Tapering, Oblong, Clavate, and Fusiform.

Wheat Rachis Margin Pubescence

Diagram of wheat rachis margin pubescence. Description follows.
Description for photo - Description of diagram of wheat rachis margin pubescence

This diagram shows two types of rachis margin pubescence - glabrous and non-glabrous.

Wheat Culm Shape of Neck

Diagram of the shape of the neck of the wheat culm. Description follows.
Description for photo - Description of diagram of the shape of the neck of the wheat culm

This diagram shows two shapes of the neck of the wheat culm - Straight and Curved.

Wheat Glume Beak Shape

Diagram of wheat glume beak shape. Description follows.
Description for photo - Description of diagram of wheat glume beak shape

This diagram shows three different glume beak shapes - Obtuse, Acute, and Acuminate.

Wheat Glume Shoulder Shape

Diagram of wheat glume shoulder shape. Description follows.
Description for photo - Description of diagram of wheat glume shoulder shape

This diagram shows six types of glume shoulder shape - Wanting, Oblique, Rounded, Square, Elevated, and Apiculate.

Wheat Glume Shoulder Width

Diagram of wheat glume shoulder width. Description follows.
Description for photo - Description of diagram of wheat glume shoulder width

This diagram shows three types of wheat glume shoulder width - Narrow, Medium, and Wide.

Wheat Glume Pubescence

Wheat glume pubescence. Description follows.
Description for photo - Description of wheat glume pubescence

This drawing shows two types of glume pubescence - Glabrous and Pubescent.

Spike and Spikelet Characteristics of Einkorn, Emmer and Spelt

This diagram shows the spikes of Einkorn, Emmer and Spelt. Description follows.

This diagram shows the spikelets of Einkorn, Emmer and Spelt. Description follows.

Description for photo - Description of diagram of the spike and spikelet characteristics of Einkorn, Emmer and Spelt

Two photographs are presented; the first a photo of the spikes of Einkorn, Emmer and Spelt; the second a photo of the spikelets of Einkorn, Emmer and Spelt.

Appendix IV: Barley (Hordeum vulgare L.) Description and Illustrations

There are two main types of cultivated barley: two-row and six-row. Each type has three spikelets at each rachis node (one central and two laterals), and each spikelet contains one floret. Groups of spikelets are arranged in an alternate and opposite fashion on the rachis. The lateral spikelets of two-rowed barley are sterile and the central is fertile, resulting in two rows of kernels on the rachis. All florets of six-rowed barley may be fertile, resulting in six rows of kernels when viewed in cross section or from the top of the spikelet. Cultivated barley species are naturally self-pollinating.

In addition to the main two-row versus six-row distinguishing factor, barley varieties also vary in that they may be winter or spring, hulled or hulless, for forage or grain, and for malting or feed purposes. Some forage barley varieties have increased isolation requirements as specified by the variety developer. This additional requirement can be found in the "Additional Comments" section of the DoV.

Unlike wheat, the characteristics identifying barley are considered as definitive in that they do not vary over a range, resulting in greater certainty when identifying varieties. The following characteristics are to be considered for observations of varietal purity and identity during seed crop inspection.

Barley Plant Characteristics After Heading:

Many characteristics useful in distinguishing barley varieties are best observed when the seeds on the head are ripe. These characteristics may not be present if inspections are conducted before the seed has fully matured. For this reason, some of the following information may not be entirely useful as seed crop inspections are usually conducted after the grains begin to mature.

Kernel: In six-row varieties, the central kernels are slightly larger and plumper than the lateral kernels, while the kernels of two-row varieties are all uniform in shape and size. The length of hair on the rachilla can be useful in distinguishing between varieties. It ranges from short, to long and feathery. The colour of the aleurone layer of a dehulled barley kernel may be yellow, white or a blue shade.

Lemma awns: In some varieties, especially those with dense heads, the awns tend to spread out like a fan. In certain varieties, the lemma awns are discarded as the grain ripens. This 'dropping-off' of awns can also occur in normal varieties under certain climatic conditions such as extreme drought.

Anthocyanin: Many varieties contain this purple or red pigment in various parts of the plant in the vegetative and reproductive stages. Most pigmented varieties tend to lose this colour as the plants ripen, but some will retain the pigment in the five dorsal lateral nerves of the developing grain. Positive identification of non-pigmented varieties by reference to fully mature grain is impossible, but the anthocyanin pigment's presence can be detected in growing plant material. The best places to look are in the basal leaf sheath of the first leaf, the stem nodes and auricles, and especially in the tips of the awns if the plant is still green.

Other traits to consider when inspecting barley varieties

  • Aleurone colour
  • Awn length
  • Collar shape
  • Glume awn barbs
  • Glume hair length
  • Glume length
  • Glume pubescence
  • Head attitude
  • Head length
  • Head shape
  • Head waxiness
  • Height (stem plus spike)
  • Lemma awn tip colour (anthocyanin)
  • Rachilla hair length

Barley Diagrams

Barley Kernel

Diagram of barley kernel. Description follows.
Description for photo - Description of diagram of barley kernel

The diagram depicts a whole barley kernel and identifies the lemma awn, lemma, crease, palea, rachilla, marginal nerve (barbed), mid-nerve, lateral nerve and the basal marking.

Barley Glume Length

Diagram of barley glume length. Description follows.
Description for photo - Description of diagram of barley glume length

This diagram shows three different lengths of the glumes of barley - short, long, and medium.

Length of Barley Awns' Extension (relative to ear length)

Diagram of length of barley awns extension. Description follows.
Description for photo - Description of diagram of length of barley awns extension

This diagram shows three different lengths of the extensions of barley awns relative to the length of the ear - longer, equal, and shorter.

Barley Awn Attitude

Diagram of barley awn attitude. Description follows.
Description for photo - Description of diagram of barley awn attitude

This diagram shows three different attitudes of the awns of barley - parallel, broad, and triangular.

Barley Rachilla Hairs

Diagram of barley rachilla hairs. Description follows.
Description for photo - Description of the diagram of barley rachilla hairs

This diagram shows two different types of hairs on the rachillas of barley - long-haired, and short-haired.

Barley Collar Shape

V-Shaped: The collar has a raised margin on the rear part with the forward part protruding downwards.

Diagram of barley V-shaped collar. Description follows.
Description for photo - Description of the diagram of barley V-shaped collar

This diagram shows that the collar has a raised margin on the rear part with the forward part protruding downwards.

Platform: The entire upper surface of the collar is almost flat or convex. The margin or edge of the collar is flat or slightly sloping downwards.

Diagram of barley platform-shaped collar. Description follows.
Description for photo - Description of the diagram of barley platform-shaped collar

This diagram shows that the entire upper surface of the collar is almost flat or convex. The margin or edge of the collar is flat or slightly sloping downwards.

Cup: The margin is raised to create a cup-like structure. The base of the first rachis segment is concealed.

Diagram of barley cup-shaped collar. Description follows.
Description for photo - Description of the diagram of barley cup-shaped collar

This diagram shows that the margin is raised to create a cup-like structure and the base of the first rachis segment is concealed.

Open: The forward part of the collar is not complete like the other types, but forms a deep open slit for a considerable way down the stem.

Diagram of barley open-shaped collar. Description follows.
Description for photo - Description of the diagram of barley open-shaped collar

This diagram shows that the forward part of the collar is not complete like the other types, but forms a deep open slit for a considerable way down the stem.

Barley Spike Attitude

Diagram of barley spike attitude. Description follows.
Description for photo - Description of the diagram of barley spike attitude

This diagram shows five different barley spike attitudes - erect, semi-erect, horizontal, semi-nodding, and nodding.

Barley First Rachis Segment

Diagram of barley first rachis segments. Description follows.
Description for photo - Description of the diagram of barley first rachis segments

This diagram shows three different types of barley first rachis segments - slightly curved, curved, and straight.

Appendix V: Oats (Avena sativa, A. nuda) Description and Illustrations

Oat is an annual, self-pollinating grass for which out-crossing seldom exceeds 0.5%. The stem is composed of a series of nodes and internodes with alternate leaves. The stem usually contains four to seven elongated internodes and the uppermost internode is often as long as the combined length of all other internodes.

Mature stems terminate in a loose, open panicle. The main axis of the panicle terminates in a single spikelet. Alternate groups of branches arise from the main axis and each branch terminates in a single spikelet. The number of spikelets per panicle normally ranges from 25 to 45 depending on genotype and growing conditions. Each spikelet usually contains from one to three florets enclosed in empty glumes with the tip of one glume extending slightly above the other. Usually only the two basal florets are fertile, but on occasion three or more are fertile.

Each flower is perfect and has three stamens, a pistil and two lodicules. The flower is enclosed by two bracts, the lemma and palea, which are known as the hulls on the harvested oat grain. While both spring and winter types of oats exist, winter hardiness in oats is not sufficient to allow winter crops of oats to survive in Canada.

Oat plant characteristics after heading

The following characteristics are to be considered for observations of varietal purity and identity during seed crop inspection.

Panicle type (Head shape): Varieties can be divided into two groups according to their panicle type. Varieties whose panicles are equilateral or equal-sided give the general appearance of a triangle or cone. This arrangement is the most common.

Varieties whose panicles are unilateral appear one-sided so that all the branches tend to be on one side of the main rachis of the panicle. These varieties are sometimes referred to as "side oats". Unilateral panicles tend to lean over due to the lop-sided weight of the grains and can be easily identified when found as a contaminant in a crop of plants with equilateral panicles. Sometimes, however, this trait is not the result of a contaminant, but a border row effect whereby equilateral varieties resemble unilateral varieties along the outside of border rows due to excess water along the field's edge. Unilateral panicles may possess a thickened swelling or false node below the lowest whorl of branches.

Semi-unilateral and sub-unilateral varieties exist in that some branches do not conform entirely to the unilateral characteristic. A few varieties change from the equilateral type to semi-unilateral as they ripen.

Length of hairs or spines on lower panicle node: Panicle branches arise from nodes on the flowering stem. The bases of these branches are generally swollen and covered with very small spines or hairs. Varieties can be distinguished by the number and relative length of these hairs on the swollen bases.

Rachilla characteristics: (observe at green stage shortly after heading) The rachillas on the upper region of the panicles possess certain features which can be used in the observation of varietal purity and identity.

Rachilla grooves: In many varieties the rachilla has two longitudinal depressions down each side of a central raised section. These depressions are often grooved and the extent to which they extend down the rachilla is a varietal characteristic.

Rachilla pubescence: In most varieties the rachilla is glabrous, though some varieties have short hairs, spines or barbs which are attached to the surface of the rachilla.

Lemma awn presence: In certain varieties, most primary grains may have awns arising from the median nerve on the dorsal side of the lemma. The presence or absence of awns and the number of primary grains producing these awns can be greatly influenced by environmental factors thus caution should be used when observing this characteristic.

Other traits to consider when inspecting oat varieties

  • Angle between rachis and dominant side branch angle
  • Average number of florets per spikelet
  • Height (including panicle)
  • Number of panicle branches
  • Number of panicle whorls
  • Panicle branch length
  • Panicle branch position
  • Presence of secondary rachis node
  • Rachis shape

Oat Diagrams

Oat Panicle Characteristics

Diagram of the oat panicle characteristics. Description follows.
Description for photo - Description of the diagram of the oat panicle characteristics

The diagram shows the oat panicle characteristics - flowering stem or culm, upper culm node, leaf sheath, flag leaf, whorl of branches arising from node, main stem or rachis, branch (of rachis), and oat spikelet.

Oat Panicle Shape

Diagram of oat panicle shape. Description follows.
Description for photo - Description of diagram of oat panicle shape

This diagram shows two different oat panicle shapes - equilateral, and unilateral.

Oat Panicle Branch Position

Diagram of oat panicle branch position. Description follows.
Description for photo - Description of diagram of oat panicle branch position

This diagram shows five different panicle branch positions - erect, semi-erect, horizontal, drooping, and strongly drooping.

Appendix VI: Triticale (Triticosecale) Description

Triticale is a cross between wheat and rye. Morphologically it resembles its wheat parent, but exhibits the more vigorous growth characteristics of rye. Triticale has either a spring or winter growth habit, has variable plant height and tends to tiller less than wheat.

The inflorescence of triticale is a spike resembling that of wheat more than rye, and is often considerably larger than that of wheat or rye. As with both parents, the spike of triticale is composed of a series of some 30 to 40 spikelets arranged alternately on each side of the rachis. Each spikelet consists of four to eight florets, of which usually only three are fertile. Each spikelet is surrounded by two glumes of chaff, and the lemma and palea enclose each floret in the spikelet. The lemmas generally taper into a 7 to 10 cm long awn. The awn lengths vary between varieties.

Due to its free-threshing property, the lemma and palea do not adhere to the kernel during threshing. It is a self pollinating species with the pollen being released within the floret. The period of anthesis in triticale varies among varieties but generally is longer than in wheat and thus triticale is more susceptible to out-crossing. Anthesis normally begins in the central portion of the spike when the spike has completely emerged from the leaf sheath. Triticale varieties are often one or two weeks later maturing than wheat.

Other traits to consider when inspecting triticale varieties

  • Awn attitude
  • Awn colour
  • Awn length
  • Culm neck shape
  • Glume beak shape
  • Glume pubescence
  • Glume shoulder shape
  • Head attitude
  • Head awnedness
  • Head colour
  • Head density
  • Head length
  • Head shape
  • Head waxiness
  • Rachis margin pubescence
  • Stem pubescence
  • Stem waxiness
  • Straw pith
  • Supernumerary spikelets

Appendix VII: Rye (Secale cereale) Description and Illustration

Of all the cereals, rye most closely resembles wheat morphologically. Although the leaves are similar in shape to those of wheat, they tend to exhibit a typical bluish colour. Rye is typically taller and tillers less profusely than wheat. The fine pubescence covering the sheath of rye seedlings distinguishes them from other cereal seedlings. The plants have numerous, highly branching, deep roots.

The inflorescence is a rather lax, slender spike, 10 to 15 cm long. The spikelets at each node of the rachis usually contain three florets, with the two outer florets being fertile and the central one being sterile. As in wheat, the lemma and palea which enclose the floret are free-threshing. The lemmas which are longer than the glumes, taper gradually and often bear barbs on the keel, and awns of intermediate length. The kernels are longer and more slender than those of wheat.

Rye differs from other small grains in that the crop is largely cross-pollinated, as most rye plants are self-sterile, and characteristically some florets fail to set seed. The spike attitude varies with variety and can be erect or nodding. Rye varieties can be distinguished from one another by observing their spike form (fusiform, elliptic or oblong), the kernel size and shape, and the degree of blue or green colouration.

The open glume orientation of rye renders it highly susceptible to ergot. Rye has a tendency to ripen quickly which makes the heads more prone to shattering, and allows only a narrow window of time for inspection of seed crops of rye.

Other traits to consider when inspecting rye varieties

  • Degree of colouration
  • Head attitude
  • Head awns
  • Head density
  • Head length
  • Head shape
  • Head waxiness
  • Plant height
  • Stem pubescence

Rye Diagram

Rye Plant

Diagram of rye plant. Description follows.
Description for photo - Description of diagram of rye plant

The diagram depicts a rye plant and florets.

Diagram of Rye Plant Parts

Diagram of Rye plant parts. Description follows.
Description for photo - Description of Diagram of Rye plant parts

A head of rye showing the long awns, a stem showing the very short auricles, and a detail of the auricles and ligule.

Date modified: