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

ENDORSEMENT

This Seed Program Specific Work Instruction is hereby approved.

______________________________
Director, Plant Production Division

__________________________
Date

The most up to date version of this document will also be maintained on the CFIA Internet and Intranet sites. In addition, the signed original will be maintained by the National Manager, Seed Section.

0.0 INTRODUCTION

The purpose of crop inspection is to provide a third party unbiased record for the Canadian Seed Growers' Association (CSGA), reporting on the isolation, condition, and purity of the crop. It is the inspector's responsibility to describe the crop and its surroundings as observed at the time of inspection.

1.0 SCOPE

This Seed Program Specific Work Instruction (SWI) outlines the procedures that a crop inspector will follow in inspecting hybrid and composite canola crops for pedigreed seed status. These inspection procedures provide the CSGA with knowledge that production has been measured against the requirements for varietal purity and crop standards as specified by the CSGA Circular 6 Canadian Regulations and Procedures for Pedigreed Seed Crop Production. Inspection procedures for traditional Cruciferous crops are contained in SWI 142.1.2-4 Cruciferous Crop Inspection Procedures.

Licensed crop inspectors may only inspect crops producing Certified seed of the species and type for which they are licensed. Official crop inspectors may:

inspect crops producing Certified seed of hybrid, composite or open pollinated canola at the request of the CSGA
inspect plots producing Foundation seed and Breeder seed of parental lines
conduct crop inspection as part of a systems audit of an authorized crop inspection service or as a surveillance audit of a licensed crop inspector.

2.0 REFERENCES

The publications referred to in the development of this SWI are those identified in SPRA 111, QSP 142.1 Pedigreed Seed Crop Inspection Procedures, SWI 142.1.2-4 Cruciferous Crop Inspection Procedures, CSGA Circular 6 Canadian Regulations and Procedures for Pedigreed Seed Crop Production and Rogues and Roguing as well as:

L. Kott, Plant Breeders' Rights Descriptors for Brassica napus, University of Guelph, 1994
P. Thomas, Canola Growers' Manual, Canola Council of Canada, 1984.
Biology Document BIO1994-09, The Biology of Brassica napus L. (Canola/Rapeseed), Canadian Food Inspection Agency, 1994.
Biology Document BIO1992-02, The Biology of Brassica rapa L., Canadian Food Inspection Agency, 1992.

3.0 DEFINITIONS

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

A line - line or population which is male sterile.

B line - male fertile line capable of maintaining male sterility in the progeny of the A line.

R line - male fertile line capable of restoring male fertility in the progeny of the A line.

Composite variety - a variety created by the controlled blending of two specific lines as Synthetic Select seed. In the case of Brassica napus, the progeny of this blending must be constituted of at least 70% seed created by intercrossing of the lines and the remainder from self/sib pollination. For Brassica rapa, the progeny of the blended seed must represent 50% seed created by intercrossing of the two parental lines and the remainder from self/sib pollination.

Double-cross hybrid - the first generation of a cross between two Foundation single-cross hybrids.

Early flower stage - flowering begins with the opening of the lowest bud on the main stem and continues upward with three to five or more flowers opening daily.

Foundation single-cross - a single cross used in the production of a double cross, a Foundation three-way cross hybrid or a top-cross hybrid.

Heterosis - a marked vigour or capacity for growth often shown in the progeny of a sexual cross between organisms of diverse genetic backgrounds.

Hybridization - the crossing of genetically unlike individuals to obtain varieties with new genetic recombinations.

Off-types - plants in a seed crop which deviate in one or more characteristics from the official description of the variety.

Open pollinated - seed produced as a result of natural pollination as opposed to hybrid seed produced as a result of a controlled pollination.

Single-cross hybrid - the first generation of a cross between two specified inbred parent lines or relatively homogeneous parent populations.

Synthetic Select - a physical blend of specific proportions of seed harvested from Breeder or Foundation plots used in the production of Certified seed crops of composite varieties. Crops sown with Synthetic Select Canola/Rapeseed are for Certified status only.

Three-way cross hybrid - the first generation of a cross between an inbred parent line or parental population and a Foundation single-cross.

Top-cross hybrid - the first generation of a cross between an inbred parent line and an open pollinated variety.

Variant - any seed or plant which (a) is distinct within the variety but occurs naturally within the variety, (b) is stable and predictable with a degree of reliability compared to other varieties of the same kind, within known tolerances and c) was originally part of the variety as released. It is not an off-type.

4.0 SPECIFIC INSPECTION PROCEDURES

4.1 Preparation for Inspection

If previous land use is not provided on the application, the grower must be contacted for this information. The previous land use history for Certified production is three years for spring hybrids and composite canola and for winter hybrids. For Breeder and Foundation plot production, the previous five years of land use history must be provided.

When an inspector receives an application for inspection for hybrid Brassica juncea, unless it is specified to be hybrid mustard quality B. juncea, the inspector is to consider this crop to be a canola quality crop and inspect the crop in a manner that will allow CSGA to appraise it according to hybrid canola quality B. juncea standards.

The inspector must refer to the application to determine planting date and contact the applicant if planting dates are not provided on the application. The inspector must also contact the grower to obtain information on the planting pattern used as this is not provided on the application for crop inspection.

Variety descriptions for registered varieties of spring and winter canola are available on the Product Registration System (PRS). The parental line descriptions are also provided on PRS. Variety descriptions may contain confidential business information and are for the use of CFIA staff only. The inspector may also reference the listing of erucic acid standards for pedigreed seed, as published on the Variety Registration Office website, if the inspector needs to clarify whether the variety is a hybrid, composite, or standard open-pollinated type.

The PRS supplies limited information on the mechanism of controlled pollination of the hybrid in question as this is considered confidential business information. There are two main types of pollination control: genetic male sterility and cytoplasmic male sterility. Within each main type, there are several specific types. Knowledge of the sterility system used in the hybrid system will assist the inspector during the inspection process as some sterility systems have specific morphological characteristics associated with them. Inspectors must be aware that under some environmental conditions, sterility systems will break down producing flowers and/or plants that will shed pollen.

Inspectors must take precautions to prevent transferring pollen between different varieties. Wherever possible, the inspector should organize inspections of the same variety for the entire day. If this is not possible, the inspector should wear waterproof pants that may be rinsed with a cleanser between crops or wear disposable Tyvek suits.

4.2 Inspection Requirements

Each crop requires inspection when the A-line (female parent) is in the early flowering stage. The early flowering stage is defined as when all A-line plants have at least one open flower. For spring planted crops, the days to first flower (days from planting when 50% of plants show one or more open flowers) can range from 40 to 60 days for B. napus. In some cases, spring canola seed may be coated with a polymer and planted the prior autumn.

Inspection of these oilseed crops can differ from other crop kinds. The combination of yellow flowers and intense sunlight can be straining on the eyes. The flowers are small and the inspector must focus on the anthers to confirm the presence or absence of pollen. This can be difficult and the inspector may need to rub the anther on a finger or piece of cloth to see if yellow pollen grains can be rubbed off.

The crop can be dense and tall making it extremely difficult to walk through. The flowers produce abundant nectar that is sticky and readily catches the pollen from the crop. To prevent the inspector from carrying pollen into a different crop, the inspector must take precautions.

Hybrid and composite canola crops are inspected for isolation, varietal purity, prohibited noxious and reportable weeds, and sources of contaminating pollen. When inspecting composite or hybrid production crops planted with blended seed, inspectors are not required to verify the proportion of parental lines planted.

When inspecting hybrid seed crop production in which parental seed is planted separately in rows or bays, formal counts are made only in the A-line and reported in the "Off-types or Other Varieties" section of the Report of Seed Crop Inspection. Sources of contaminating pollen found in the B-line or R-line are reported in the "Comments" section of the report. When inspecting crops producing composite canola or hybrid crops produced using a mixed parent seed method, counts are made throughout the crop and reported in "Off-types or Other Varieties".

Isolation distances are large. When species which may cross pollinate with the crop are found in the isolation, additional inspection time will be required to verify the isolation condition.

A cursory verification of the entire isolation distance is performed. The isolation distance for crops producing Certified hybrid seed is 800 m. The area 200 - 800 m from the crop is not walked unless a problem is identified during the cursory inspection. For hybrid canola, inspectors must note and report the following sources of contaminating pollen in the crop and within a 200 m radius from the edge of the crop: Brassica napus, B. rapa, B. juncea, Raphanus raphanistrum (wild radish) and Sinapis alba. For composite canola, these sources of contaminating pollen are to be noted in the crop and within a 100 m radius of the edge of the crop. When off-type B.napus is found in a crop of B. napus, it is reported as "Off-types and Other Varieties" section of the Report of Seed Crop Inspection. When the remaining contaminant species are found in a crop of B. napus, they are reported in the "Other Kinds and Weeds Difficult to Separate" section. When found in the isolation, these species are reported in the "Open Pollinated Crops" section.

The inspector is required to do a detailed inspection of the 50 m closest to the crop for all canola crops and plots. During this inspection, the inspector must note and report on the density, location and distance of sandrocket, wild radish and dog mustard in the Open Pollinated Crops section of the Report of Seed Crop Inspection. However, counts are not required when these species are found beyond 3 m from the crop.

4.3 Crop Inspection

Before starting the inspection the inspector must verify that s/he is in the right location and match the information from the application (including map) with the crop site.

Seed may be produced in isolation cages or under tents. Tent inspection procedures are available from the CSGA.

The crop should be walked according to the selected travel pattern. The inspector must observe and note: the isolations on all sides (distance and condition); the varietal purity of the crop (off-types and variants); and the presence of prohibited noxious, objectionable or difficult to separate weeds and/or other crops.

Where prohibited noxious or difficult to separate weeds are present in the area of the crop to be harvested, a description of maturity should be made as to whether they will likely set seed. The presence of difficult to separate weeds (cleavers bedstraw, wild radish and/or wild mustard) in the crop to be harvested is cause for declining pedigreed status. Wild radish is also considered to be a source of contaminating pollen. These weeds are to be reported quantitatively in counts. Prohibited noxious and objectionable weed presence is to be estimated using the frequency indices provided in QSP 142.1 Pedigreed Seed Crop Inspection Procedures. When reporting weeds in the crop, in the case of canola, weeds should be reported in the crop and within a 3 m area of the crop as there is a risk that they may be harvested within this area.

When composite and hybrid crops are planted with blended seed, six counts must be taken in a representative manner throughout the crop. When crops producing hybrid seed are planted in rows or bays, six counts are to be taken in the A-line. However, if sources of contaminating pollen are observed in the R-line, this must be reported in the "Comments" section of the Report of Seed Crop Inspection. When the inspector encounters fertile plants in the A-line, a determination must be made as to whether the plants are true off-types. If all flowers on the plant are fertile, it is considered an off-type. If only some flowers on the plant are fertile, this may indicate the breakdown of sterility due to environmental conditions or, in some production systems, incomplete removal of herbicide susceptible fertile plants.

The inspector may also encounter sterile plants in the A line that are waxy and darker green in the norm of the variety. These plants should be recorded in counts as "Offtypes or Other Varieties" for CSGA assessment. Inspectors may encounter plants with misformed petal arrangements, extra petals or deformed petals. These may be more prevalent in some pollination control systems. The inspector must use his/her knowledge of the pollination control mechanism to determine if these plants are offtypes to be reported in counts.

The inspector must refer to Circular 6 for the minimum isolation distances to potentially contaminating crops that have been deliberately planted. In all instances, when the inspector finds sources of potentially contaminating pollen in the isolation, the inspector must provide complete information in the "Open Pollinated Crops" section of the Report of Seed Crop Inspection. The inspector's report must include the population density, growth stage, location and distance from the crop and approximate size of the contamination. For example: "volunteer B. napus, 3 per square meter in wheat crop, early flowering, 100 m into west isolation along entire west side of crop (800 m), area of contamination is approximately 800 m x 100 m."

Pedigreed seed production crops of hybrid and composite canola are to be isolated from other canola crops and plots by 800 m and 100 m distances respectively. However, less than this distance is acceptable if the crop is adjacent to a plot of the same variety and pedigreed status. This is true for a crop planted with Foundation seed of the same male parent when the pedigree can be verified and isolation is free of contaminants. When inspecting the isolation distances around hybrid and composite canola, the following guidance should be noted:

the isolation distances established by the CSGA are the distances to be inspected to determine the presence of established crops of the species in question.

Upon exiting the crop, if the inspector is proceeding to inspect a canola plot or crop of a different variety, the inspector must take measures to eliminate the possibility of pollen spread.

4.4 Plot Inspection

Official crop inspectors may inspect both Breeder and Foundation plots. In both cases, six counts of 20000 plants are to be performed in the A-lines. It may be difficult to perform these counts due to low seeding rates. As a result of these low seeding rates, the population may be unevenly spread out. In addition, the plot may contain less than 120,000 plants. In this case, the inspector must estimate the total population size, conduct as many counts as possible on the 20000 plant count areas. For the remaining count area, the inspector will estimate and report the number of plants in the small count area, and perform the count on this smaller area.

Plot dimensions are to be reported for CSGA assessment of compliance with maximum plot size standards. Plots are to be isolated from other canola crops and plots by 800 m distance, however, less than this distance may be acceptable if the plot is adjacent to a plot of the same parental line and pedigreed status.

Upon exiting the crop, if the inspector is proceeding to inspect a canola plot or crop of a different variety, the inspector must take measures to eliminate the possibility of pollen spread.

4.5 Completion of the Report of Seed Crop Inspection

Sources of contaminating pollen found in the A-line are to be reported in the "Off-types or Other Varieties" section of the Report of Seed Crop inspection. Sources of contaminating pollen found in the B-line or R-line are to be reported in the "Comments" section. The "Open Pollinated Crops" section is used to report what is found within the isolation distances.

Key factors in completion of the report are:

Distance to potentially contaminating crops, as per section 5.4 and 13.6 of Circular 6, should be recorded in the "Open Pollinated Crops" section. For example, if none, state "None within ___m of crop", where ___ m is the isolation requirement.
Where crops planted with Certified seed of the same variety are planted within the maximum isolation distance, the pedigree of the Certified seed must be verified and the isolation distance must be free from any other pollen contaminants.
If a hybrid crop was planted with blended seed, this must be noted in the "Comments" section of the Report of Seed Crop Inspection

APPENDIX I Brassica Terminology and Biology

Oilseed rape refers to two species of plants, Brassica napus and B. rapa (Brassica rapa is also known as B. campestris). In Canada, these crops are known commonly as Argentine rape (or canola) and Polish rape (or canola) respectively, however, the use of these terms is not widespread outside of Canada. In the mid 1970's, a special type of oilseed rape was developed in Canada for the food and feed market and is called canola. Canola refers to oilseed rape that has low levels of erucic acid in its oil and low levels of glucosinolates in its meal.

Other Brassica and related crops are being bred to produce canola quality oil. Canola quality B. juncea varieties have been developed and other species of canola type material are under development. Some varieties of these other species have been granted contract registration with a requirement to be produced under a quality management system.

In addition to canola, there is Canadian production of oilseed rape varieties for industrial oil. These varieties are high erucic acid rapeseed (HEAR) types. Varieties of this type have been granted contract registration and are required to be produced under a quality management system.

Many varieties of canola are plants with novel traits (PNTs). PNTs are defined as plants containing traits not present in plants of the same species already existing as stable populations (wild or cultivated) in Canada, or are expressed outside the normal statistical range of similar existing traits in the plant species. Plants with novel traits may incorporate new traits derived from traditional plant breeding methods such as mutagenesis or from newer breeding methods such as recombinant DNA technology. Plants or varieties whose novel traits were developed using this latter technique are also referred to as genetically modified organisms (GMOs).

Herbicide tolerant canola refers to canola that is tolerant of a herbicide to which tolerance is not native to the North American population of canola. Due to the biology of canola, it is difficult to achieve canola seed that is completely herbicide tolerant. As a result, breeders will specify an acceptable limit of plants in the variety that are susceptible to the herbicide in question but that otherwise conform to the norm of the variety. The acceptable level of variants depends, to a large extent, on whether the variety is a hybrid, a composite or an "open-pollinated" variety.

Brassica crops are also classified according to their end-use. Although Canadian production of canola is primarily for oil and feed purposes, varieties of B. napus may also be produced for forage purposes. Some varieties of B. rapa may be grazed as pasture and grown for their edible roots; these are referred to as swede rape or turnip rape or forage turnip.

The Biology of Brassica Crops

Brassica napus is a predominantly self-pollinated crop, however, in some environments outcrossing rates of up to 27% can occur. Brassica rapa is an obligate cross-pollinator. There are two types of B. napus grown in Canada. While the spring type is predominantly grown, both open-pollinated and hybrid types of winter canola are commercially available. Winter canola requires a period of cold temperature in order to flower and is not to be confused with the fall seeding of spring canola seed that is protected by a polymer coating to provide for early spring germination.

Flowering begins with the opening of the lowest bud on the main stem and continues upward with three to five or more flowers opening per day. Flowering at the base of the first secondary branch begins two to three days after the first flower opens on the main stem. Under reasonable growing conditions, flowering of the main stem will continue for two to three weeks in both B. napus and B. rapa.

Flowers begin opening early in the morning and, as the petals completely unfold, pollen is shed and dispersed by both wind and insects. Flowers remain receptive to pollen for up to three days after opening. If favourable, warm, dry weather occurs, nearly all the pollen is shed the first day the flower opens. In the evening the flower partially closes and opens again the following morning. Fertilization occurs within 24 h of pollination. After fertilization, the flower remains closed and the petals wilt and drop. A young pod becomes visible in the centre of the flower a day after the petals drop.

During flowering the branches continue to grow longer as buds open into flowers and as flowers develop into pods. In this way the first buds to open become the pods lowest on the main stem or secondary branches. Above them are the open flowers and above them the buds which are yet to open. All of the buds that will develop into open flowers on the main stem will likely be visible in B. napus within three days of the start of flowering and within 10 days in B. rapa.

Trait	B. rapa	B. napus	B. juncea	Sinapis alba
Seedling Leaves	spiny underside, wrinkled	glabrous underside, smooth	glabrous underside, smooth	spiny underside, very wrinkled
Leaves	yellow-green to green, upper leaves clasping stem	waxy, blue-green, partially clasping stem	green, terminate above stem, lower leaves lobed, upper leaves narrow and entire	light green, deeply lobed, terminate above stem
Flowers	smaller, deeper yellow petals, compact bud clusters, buds born below open flowers (umbrella shape)	larger, lighter yellow petals, buds born above uppermost open flowers	pale yellow flowers similar to B. rapa	smaller, mid- yellow flowers, elongated racemes
Stems	smooth	smooth	smooth	hairy
Pods	smaller, shorter pod, smooth long conical beak, right angles to raceme	larger, medium pod, smooth medium conical beak, right angles to raceme	smooth, long conical beak partially appressed to raceme	spiny long flat beak right angles to raceme
Pollination	must cross pollinate	predominantly self-pollinating	predominantly self-pollinating	must cross pollinate
Attitude	many branches, up to 20, leads to less structured look, more difficult to identify main stem, height 50-125 cm	fewer branches, thicker, taller, height 75 - 175 cm	fewer branches, long and upright, intermediate height	fewer branches, upright, shorter

APPENDIX II Other Crops to be Reported

Crop	Crop(s) Difficult to Separate
Canola	Mustard, Oilseed Radish

Crop	Sources of Contaminating Pollen in Crop
Brassica napus	B. rapa, B. juncea, and Sinapis alba
Brassica rapa	B. napus, B. juncea, and Sinapis alba
Brassica juncea	B. napus, B. rapa, and Sinapis alba

APPENDIX III Reportable Weeds

Weeds Difficult to Separate (to be reported in counts)	Objectionable Weeds (to be reported by frequency)
Cleavers (bedstraw), Wild mustard, Wild radish	Stickseed, Smartweed, Cruciferous weeds. (e.g. Ball mustard, dog mustard)

APPENDIX IV Acceptable Abbreviations for Canola Seed Crop Inspection Reports

AC	apetalous canola
FIS	fertile plants in sterile row/bay
NAPUS	napus (Argentine type canola)
PW	petals - white
RAPA	rapa (Polish type canola)
ST	sterile plants
WM	wild mustard

APPENDIX V: Diseases That May Affect Plant Appearance

Yellow or reddish-brown streaks, often occurring only on one side of the stem and/or on the branches. Some plants may have an orange discolouration at the base of the stem. Severely infected plants die prematurely. Stems and/or branches turn brown, but plants remain upright with roots intact. There are no visible lesions on stems or roots - fusarium wilt

Severely affected plants are stunted and wilt under moisture stress because much of the taproot is destroyed - clubroot

Hard brown lesions at stem base, salmon coloured spore masses often present - foot rot

Light brown lesions on tap root and at bases of larger roots, tap root girdled, leaving a stump - brown girdling root rot

Whitish spots on leaves and stems peppered with small dark fruiting bodies; stem lesions may be shallow and grey or black - weakly virulent blackleg

Whitish spots on leaves and stems with small dark fruiting bodies; deep stem cankers that are brown with a dark rim; may cause severe lodging and ripening with shrivelled seed - virulent blackleg

Premature ripening of plants; bleached stems that tend to shred; hard black Sclerotia inside stems near stalk base and other bleached areas - Sclerotinia stem rot

Black, brown or greyish spots on leaves, stems and pods; pod splitting may occur - Alternaria black spot

While leaf spots, large purple to grey speckled stem lesions - "White leaf spot" "Grey Stem"

White to cream-colored masses, or pustules of "white rust", on the underside of leaves from the seedling stage onward. Following infection of the stems and pods, raised green blisters form that turn white during wet weather. The most conspicuous symptom is the presence of swollen, twisted and distorted inflorescences called "stagheads" that become brown, hard and dry as they mature - White Rust (Staghead)

Infected plants fail to set pods or produce blue-green, sterile, hollow bladders in place of normal pods. Normal pods may be present on the lower portions of infected plants - Aster Yellows

Appendix VI Nutritional Deficiencies That May Affect Plant Appearance

Sulphur Deficiency Symptoms

On fields marginally deficient in sulphur, canola plants may show no obvious visual symptoms, but can have seriously reduced yields. When visual symptoms of sulphur deficiency are noticeable, the canola crop is severely lacking in sulphur. Symptoms are most likely seen at the bud and flowering growth stages because of the crop's high need for sulphur during this period. Because sulphur is a constituent part of protein it is not mobile in the plant. This means it does not move readily from lower leaves to younger upper leaves. Therefore, the new leaves, flowers and pods at the top of the growing branches are more likely to be deficient in sulphur than the older leaves at the bottom of the plant. When soil sulphur supplies are limited, the youngest, last formed tissue goes without.

A deficiency of sulphur will cause a general yellowing of younger leaves in the initial stages because of the involvement of sulphur in the formation of chlorophyll. This yellowing gradually progresses to all leaves. With a severe deficiency the leaves tend to be poorly developed and cupped, particularly in the upper portion of the plant, with a purple color on the backs of the leaves. The symptoms are not quite as severe on the bottom of the plant as they are on the top of the plant. In a moderate sulphur deficiency the upper leaves may be cupped while the lower leaves appear healthy. The flowers are often paler than normal for the variety; pale yellow instead of dark yellow, almost white instead of pale yellow. Flowering is delayed and prolonged so that at maturity, which is delayed, the plants are carrying both mature and green seed pods, flowers and buds. There is a reddish-purple tinge to the leaves, stems and pods. Pods form slowly and are small and poorly filled with shrunken and shriveled seeds. The number of pods decreases towards the upper part of the plants with many seeds aborted or the pods totally empty. The plants tend to stand erect because there is little weight in the pods and the stems are shorter and tend to be woody. These symptoms commonly occur in patches in the crop and are easily seen at maturity; however, on severely deficient soils entire crops can be affected.

Nitrogen Deficiency Symptoms

Vigorous, healthy growing canola plants with adequate nitrogen usually have a deep green color. When a plant is not able to get enough nitrogen from the soil to satisfy its needs, the first symptoms of deficiency are a light green coloration to the leaves and stem. The nitrogen in older leaves is redistributed to younger leaves to maintain growth. As a result, the older leaves first show the characteristic yellowing which indicates nitrogen deficiency. Other leaves may become greenish-yellow often showing a purple discoloration. Older leaves may wither. The plants grow poorly, with short, thin main stems and few branches, and the crop canopy remains thin and open. Flowering takes place over a short period of time and pod numbers are low.

Phosphorous Deficiency Symptoms

Lack of available phosphorus restricts root and top growth, resulting in poorly developed root systems; spindly, thin, erect stems with few branches; and small narrow leaves. A severe phosphorus deficiency may show up as a dark bluish-green coloration of the leaves, often accompanied by purplish tinges. The stems may also be bluish-green sometimes with purple or reddish coloration as well.

Potassium Deficiency Symptoms

When a soil is deficient in potassium, plant growth is reduced resulting in smaller leaves and thinner stems. Also, responses to nitrogen and phosphorus will be small. Plants tend to wilt. In severe cases of potassium deficiency, the edges of older leaves will become yellow or scorched and may die completely but remain attached to the stem.

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