AFDC 30 (1913 ) DTZS  
      DRAFT TANZANIA STANDARD  
 
 
 
 
 
 
 
 
Cowpea ( Vigna unguiculata  (L.) Walpers ) seed — Requirements for 
certification  
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
                    TANZANIA BUREAU OF STANDARDS  
 AFDC 30 (1913 ) DTZS  
  
Cowpea (Vigna unguiculata  (L.) Walpers ) seed — Requirements for 
certification  
 
1. Scope  
This Tanzania standard specifies the certification requirements for pre-basic, basic  and certified seed of 
cowpea  (Vigna unguiculata  (L.) Walpers) . 
 
2. Normative references  
The following documents are referred to in the text in such a way that some or all of their content 
constitutes requirements of this document. For dated references, only the edition cited applies. For 
undated references, the latest edition of the referenced document s (including any amendments) applies.  
International Rule s for Seed Testing Published by the International Seed Testing Association (ISTA)  
OECD Seed Schemes for Varietal Certification or the Control of Seed Moving in the International Trade   
OECD Seed Schemes; Guidelines for Control Plot Tests and Field Inspecti on of Seed Crops  
 
3. Terms and definitions  
For the purposes of this standard , the terms and definitions given in ISTA and OECD together with the 
following shall apply;  
3.1 
seed test certificate  
legal document issued by the national seed certification authori ty, which states that a seed lot has met the 
prescribed requirements set in this standard  
3.2 
distinctness  
variety is deemed to be distinct if it is clearly distinguishable in at least one character from any other 
variety whose existence is a matter of com mon knowledge at the time of filing the application for 
registration  
3.3 
field 
defined and identifiable area of land or facility that is used to produce a seed crop under the Seed 
Certification Scheme  
3.4 
field inspection  
examination  of a field and or seed  crop, by an inspector to check if the  prescribed  requirements for seed  
certification have been satisfied  
 AFDC 30 (1913 ) DTZS  
 3.5 
field number  
number assigned to the field by the national seed certification authority, when the application form for 
certification is submitted  
3.6 
germination  
emergence of plumule and radicle and development of a seedling to a stage where the aspect of its 
essential structures indicates whether or not it is able to develop further into a satisfactory plant under 
favourable conditions in the field  
3.7 
seed grower  
person or entity registered to produce seed  
3.8 
inert matter  
seed units and all other matter and structures not defined as pure seed or other seeds  
3.9 
isolation  
prescribed  distance or time between crops of cowpea  that is required to preve nt contamination either 
mechanically or by cross pollination  
3.10 
inspector  
authorized or licenced official responsible for carrying out field examination for seed  certification purposes  
3.11 
international seed testing association rules  
instructions for se ed testing that should be adhered to seed testing published by the International Seed 
Testing Association  (ISTA).  
3.12 
label  
tag or other device that is attached to , written, stamped, or printed on any container of seed or that 
accompanies any lot of bulk seed and which describes the kind of seed and any other information 
required by relevant regulation  
3.13 
previous cropping  
prescribed  period (seasons or years) that must elapse between the production of a crop of the same 
species in a field and the product ion of a crop entered in the certification scheme in the same field  
3.14 
maintainer  
person or organisation responsible for the production or maintenance of a bred variety included in a 
national list of varieties/variety catalogue eligible for certification , and ensure that the variety remains true 
to type throughout its full life -span .  
3.15 
national seed certification authority  
national  designated  authority responsible for conducting seed certification processes  AFDC 30 (1913 ) DTZS  
 3.16 
noxious weed  
weed species  or its  seed s which is difficult to separate during processing or has undesirable effects on 
the crop produced . 
3.17 
off-type 
plant of the same species which does not exhibit the recognised and accepted habit and characteristics of 
the variety being grown  
3.18 
other see ds 
seeds of any plant species other than that of the crop sample that is being tested. They consist of weed 
seeds and other crop seeds  
3.19 
post -control plot  
small plot where a representative sample of a seed lot is grown to determine the identity and puri ty of the 
variety and to check if the seed certification system is operating satisfactorily  
3.20 
pure seed  
species stated by an applicant, or found to predominate in a test, and includes all botanical varieties and 
cultivars of that species, including inta ct seeds and pieces of seed units larger than one -half their original 
size 
3.21 
variety registration  
listing of an approved new variety in a national variety catalogue after it has been tested and satisfied the 
prescribed requirements for distinctness, uni formity, stability, and has value for cultivation and use  
3.22 
rogueing  
removal of off -types and diseased plants or any other unwanted plant from a seed crop if they may 
reduce the quality of the harvested crop  
3.23 
seed certification  
process by which the quality and identity of a seed lot is assured  through official control and inspection by 
designated seed certification authority  
3.24 
seed lot  
defined quantity of seed bearing the same reference number and for which the origin, production history 
and ident ity is known  
3.25 
stability  
condition where distinguishing characteristics of a variety remain unchanged after repeated growing 
cycles  
3.26 
uniformity  
condition of a variety subject to the variation that may be expected from the particular features of  its 
propagation, to remain sufficiently homogeneous in its relevant characteristics  AFDC 30 (1913 ) DTZS  
  
3.27 
variety  
assemblage of cultivated plants that is clearly distinguished from other varieties by any characters 
(morphological, physiological, cytological, chemical, or othe rs) and which retains its distinguishing 
characteristics when reproduced by the normal means for the crop and variety  
3.28 
variety catalogue  
list of varieties that have been registered by a national designated authority  
3.29 
carryover seed  
seed produced and certified in previous season and stored for one or more cropping seasons / or past its 
valid test duration  
 
3.30 
seed  
planting materials used for generative propagation of plants  
3.31 
breeder seed  
nucleus seed from the breeder that is used to produce pre -basic seed  
3.32 
pre-basic seed  
seed that is derived from breeder seed that is used to produce basic seed through one cycle of 
multiplication  
3.33 
basic seed  
seed that has been produced from breeder or pre -basic seed that is used for the production of cert ified 
seed  
3.34 
certified seed  
seed that is produced from basic seed through one or two generations of multiplication  
3.35.1 
certified seed 1st generation  
first generation of seed derived from basic seed  
3.35.2 
certified seed 2nd generation  
certified seed 2nd generation which is multiplied once and from certified seed 1st generation  
 
 
 AFDC 30 (1913 ) DTZS  
  
4. General requirements  
Key parameters required to implement this standard are elaborated in the variety descriptors, the field 
and laboratory requirements  
4.1 Eligible vari eties  
4.1.1 Varieties eligible for seed certification shall be those registered in the national list of varieties/ variety 
catalogue.  
4.1.2 The national seed certification authority shall keep the official descriptor of the varieties in hard and 
electronic copies.  
4.2 Inspection and laboratory testing  
4.2.1 The minimum information for an application for certification of a seed crop shall include the 
following:  
a) name, address and contact details of the seed grower;  
b) crop and variety to be sown;  
c) physical locatio n; 
d) area and reference number of the field, and its cropping history for the past two cropping 
seasons;  
e) class of seed to be produced; and  
f) registration number of the seed grower.  
4.2.2 Information and records related to the previous cropping history, origin of seed planted, and field 
inspections shall be kept and used for certification to ensure full traceability of quality, genetic identity and 
purity of the seed harvested.  
4.2.3 The inspection of seed crops shall be done in accordance with OECD Seed Schemes ; Guidelines 
for Control Plot Tests and Field Inspection of Seed Crops. If the field is found to be in conformity with the 
standards stated in Field requirements (Table 1) it is approved.  
4.2.4 The seed lot shall be sampled and tested in an official or aut horized laboratory. The sampling and 
testing of seed lots shall be done in accordance with the relevant procedures described in the ISTA rules.  
4.2.5 A seed lot that conforms to the standards set out in laboratory requirements (Table 2 ) shall be given 
a seed test certificate and a unique reference number to confirm its status under the certification scheme. 
One part of the seed sample shall be retained for sowing in a post -control plot in the next season  
5. Seed classes  
For the purpose of this standard, the  following classes of seed shall apply:  
a) Pre-basic  seed;  
b) Basic seed ; and  AFDC 30 (1913 ) DTZS  
 c) Certified seed:  
· 1st generation (C1); and  
· 2nd generation (C2).  
 
6. Land Requirements  
6.1.  Land to be used for seed production of cowpea shall be free of volunteer plants , noxious weeds and 
soil borne disease .  
6.2.  Cowpeas shall not be grown on land which was planted to cowpeas the previous year unless the 
preceding  crop was grown from certified seed of the same variety.  
 
7. Field requirements  
7.1. A field producing a see d crop of cowpea shall be approved for certification if it complies with the 
requirements in Table 1  
Table 1. Field requirement for certification  
 
S.No  Variable  Pre-basic  Basic  Certified 1  Certified 2  
i.  Previous cropping 
(seasons before), min.  1 1 1 1 
ii.  Isolation, m, min.  25 20 10 10 
iii.  No. of inspection, min  2 2 2 2 
iv.  Off-types (%), max.  0.1 0.2 0.5 0.5 
v.  Noxious weeds 
(No./1000plants)  0.3 0.5 1 1 
vi.  Diseases (%), max  
• Common Blight  0.02  0.02  0.03  0.03  
 
• Halo blight  0.01  0.01  0.02  0.02  
• Charcoal rot  0.01  0.01  0.02  0.02  
• Mosaic virus  0.01  0.05  0.1 0.1 
• Anthracnose  0.02  0.02  0.03  0.03  
 AFDC 30 (1913 ) DTZS  
 7.2 Fields may be rejected for certification because of unsatisfactory condition caused by noxious 
weeds, poor growth, poor stands, excessive disease presence, insect damage, and any other condition 
that prevents accurate inspection or creates doubt as to the identity of the variety.  
7.3 The Field inspection  report shall be i ssued in accordance with Annex A  
 
8. Seed sampling and laboratory standards  
8.1 The harvested se ed from the field approved for certification shall be kept as an identified unit until 
processing. After processing, sampling shall be done in accordance to ISTA rules and submitted to the 
laboratory for testing where a conformed sample shall be given a ce rtificate with a unique lot number for 
the purpose of tracking.  
8.2 The maximum size of a seed lot for certification purposes is 30 000 kg; lots larger than this shall be 
divided and given separate lot numbers.  
8.3 An inspector shall draw a representative submitted sample from each lot according to ISTA rules.  
8.4 The submitted sample shall be divided into three sub -samples, one for testing in the laboratory, one to 
be stored for reference purposes in case re -testing is necessary, and one for the post -contr ol tests. The 
samples shall be marked with the same identification as the seed lot, securely sealed and shall be stored 
in cool and dry conditions to prevent contamination and loss of germination.  
8.5 Laboratories authorized by the national seed certificat ion authority to conduct seed testing for 
certification shall follow the methodology established in the ISTA rules for cowpea  seed.  
8.6 The seed lots shall comply with the laborator y requirements specified in Table 2 . 
 
Table 2  — Laboratory requirements  for certification  
S.No  Variable  Pre-basic  Basic  Certified 1  Certified 2  
 Pure seed (%), min.  99 99 99 99 
 Other seeds (%), max.  0.1 0.1 0.1 0.1 
 Weed seeds (number/kg)  5 5 10 10 
 Noxious weed  None  None  None  None  
 Innert matter (%), max  0.9 0.9 0.9 0.9 
 Moisture content (%), max.  10 10 10 10 
 Germination (%), min  85 80 80 80 
 Diseases (%), max  
• Charcoal rot  0.01 0.01 0.02 0.02 
 
• Halo blight  0.1 0.1 0.2 0.2 
• Mosaic virus  0.01 0.05 0.1 0.1 
• Anthracnose  None  None  None  None  AFDC 30 (1913 ) DTZS  
  
8.7 The laboratory te st report shall be i ssued in accordance with Annex B  
 
9. Certificates  
10.1 The seed test certificate for a seed lot shall be signed and issued by the national seed certification 
authority and shall include all information presented in Annex C. This certifi cate shall be valid for a period 
of seven  months.  
10.2 Carryover seed shall be re -sampled and retested for germination. If the test result complies with the 
prescribed  standards, a new test certificate shall be issued for the seed lot, which cancels the pr eviously 
issued certificate, and shall include the certificate number of the cancelled certificate.  
 
 10. Packaging and labelling  
10.1 All classes of seed that have been certified shall be packaged in new containers which shall be 
marked with the company n ame and crop species and shall have the official label of the national seed 
certification authority.  
10.2 The labels for each class are identified by the following colours:  
➢ Pre-basic seed: Violet band on white  
➢ Basic seed: White  
➢ Certified Seed 1st generatio n: Blue  
➢ Certified Seed 2nd generation: Red  
10.3  If seeds are treated with any chemical or product harmful for human or animal consumption, the 
container shall carry a label stating the chemical or product used and warning of the health risks  using 
English  and Swahili . 
10.4 The labels sha ll be prominent, indelible, legible and fixed to the containers by an authorized person 
in such a way that they cannot b e destroyed or easily removed. The following information shall be 
included on the official labels:  
• name  of the crop, “Cowpea  seed”;  
• species (Latin name);  
• variety denomination;  
• seed lot number;  
• test certificate number;  
• date of test;  
• net weight;  
• seed treatment declaration  
• logo of the national certification authority;  AFDC 30 (1913 ) DTZS  
 • name and address of certifying authority;  
• seed class;  
• year and country of production; and  
• statement of re -packing and re -labelling (if applicable).  
 
10.5  All containers/bags shall be closed either by hand or machine stitching and shall be sealed in 
such a way that if they are opened illegally, t hat violation can be detected.  
 
10.6 Repackaging and relabelling are authorized in the following cases:  
a) The national seed certification authority may authorize the re -packaging and re -labelling of a particular 
seed lot that is produced in another countr y, but shall retain the original label information of the producing 
country; and  
b) Blending of a seed lot with other lots of the same variety and class (generation) is allowable if all seed 
lots of the blend have met the field and laboratory requirements for certification prior to blending. A new 
lot number shall be issued. Details of the blended lots and their proportions shall be kept by the certifying 
authority for traceability.  
 
11 Post -control tests  
The Post control tests shall be carried out in accor dance with OECD Schemes for Varietal Certification or 
the Control of Seed Moving in the International Trade  
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 AFDC 30 (1913 ) DTZS  
  AFDC 30 (1913 ) DTZS  
 Annex  A 
(normative)  
 
Field inspection report  
Reference number..................  
Date of the report....................  
 
Seed grower information  
Name ……………………………………. Address ………………………………………  
Telephone: ……………………………… E -mail.............…………………………………  
Registration number……………………. Number of inspections....................................  
Field location  
Province/Region......................... ..................... District ...............................Sector .......………….…….........  
Latitude................................................................. Longitude ………………. Field number..................... .........  
Field size (Ha/acre) ………………… ……......... Cropping season ………. Crop species ……………............  
Seed class ………………………….…………… Variety ………………… Previous cropping………………  
Variable  Observations/results  Comments/remarks  
Isolation, m    
Off types    
Noxious weeds    
Deliberative disease  
    
   
   
   
   
Other crops    
General conditions of the crop (for example, 
drought, crop husbandry, etc.)    
 
 
 
 
 AFDC 30 (1913 ) DTZS  
 Decision  
Decision on the approval  Justification  
The seed crop is approved for 
certification   
The seed crop is not 
approved for certificat ion  
 
Name of seed grower                                   Name of Inspector       
 
Date &si gnature                                  Date, signature & Stamp     
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 AFDC 30 (1913 ) DTZS  
 Annex  B 
(informative)  
 
Seed laboratory test report  
Name of seed grower  
Species, variety, class, weight of lot  
Testing and Issuing laboratory  
Sampled by  
Test number  
Country of origin  
Label serial number  
Seed Lot Reference Number:  
 
Number of 
containers  Date of sampling  Date sample 
received  Date test(s)  
concluded  
 Test number  
 
     
ANALYSIS RESULTS  
Purity  Germination  Moisture  
content,  
% 
 Pure 
seed  
% 
 Inert 
matter,  
% 
 Other  
crop 
seeds  
% Weed  
seeds,  
per kg  Number  
of days  
 Normal  
seedling  
s, 
% 
 Hard  
seeds,  
% 
 Fresh  
seeds,  
% 
 Abnormal  
seedlings,  
% 
 Dead  
seeds,  
% 
 
           
Kind of inert matter:  
Other crop seeds:  
Weed seed:  
Noxious weed:  
Other determinations  
Place  
 Date  
 Name & Signature  
 
 AFDC 30 (1913 ) DTZS  
 Annex C  
(Normative)  
 
Seed test certificate  
This certificate is issued for a see d lot which has satisfied all the requirements of the certification scheme  
  
Previously issued certificate 
number..............  Certificate No. ………….  Standard:.................  
APPLICANT INFORMATION  
Seed Lot Reference  
Number  
 Species and  
Variety  
 Class 
 Weight of lot  Number of  
containers  
     
Name of testing laboratory:  Test number:  
ANALYSIS RESULTS  
Purity Germination  Moisture  
content,  
% Pure  
seed  
% Inert 
matter  
% Other  
crop 
seeds 
% Weed  
seeds  
Per 
kg Normal  
seedlings  Abnormal  
seedlings  Fresh  
seeds Hard  
seeds Dead  
seeds 
          
Kind of inert matter:  
Kind of other crop seeds:  
Kind of weed seeds:  
Other determinations  Statement of packaging and re -labelling: 
(if 
applicable)  
 
 
 
National Seed Certification Authority  
Signature …………………………………………………… …………….  
Place and Date ………………………………………………………………….