LETTUCE (Lactuca sativa L.)

I. Application and Amplification of General Seed Certification Standards

The General Seed Certification Standards are basic and, together with the following specific standards constitute the standards for certification of  lettuce seed.  

II. Land requirements

Land to be used for seed production of lettuce shall be free of volunteer plants. 

III. Field Inspection

A minimum of three inspections shall be made, the first before heads have formed in heading types, and before full grown stage in non-heading types, the second when heads have formed heading types, and at full grown stage in non-heading types and the third at flowering stage.

IV. Field Standards

A. General requirements

1. Isolation

Lettuce seed fields offered for certification shall be isolated from the contaminants shown in the column 1 of the Table below by the distances specified in columns 2 and 3 of the said Table:

        Contaminants                                                                                   Minimum distance (meters)

                                                                                                                Foundation        Certified

            1                                                                                                         2                     3

Fields of other varieties                                                                                   50                   25

Fields of the same variety not conforming to 

varietal purity requirements for certification and

wild lettuce (Lactuca scariola L.)                                                                     50                   25    

B. Specific requirements

        Factor                                                                                              Maximum permitted (%)*

                                                                                                                Foundation            Certified

      Offtypes                                                                                               0.10                       0.20   

 ** Objectionable weed plants                                                                    0.010                  0.020

*** Plants affected by seed borne disease                                                  0.10                       0.50   

      * Maximum permitted at and final inspection.

    **Objectionable weed shall be : wild lettuce (Lactuca scariola L.)     

 *** Seed borne disease shall be: Lettuce Mosaic Virus.

V. Seed standards

        Factor                                                                                              Standards for each class

                                                                                                                Foundation            Certified

Pure seed (minimum)                                                                                98.0%                    98.0%

Inert matter (maximum)                                                                              2.0%                      2.0%

Other crop seeds (maximum)                                                                    None                     None

Total Weed seeds (maximum)                                                                    5/kg                     10/ kg

* Objectionable weed seed (maximum)                                                      2/kg                       5/ kg

Other distinguishable varieties (maximum)                                                  10/kg                     20/ kg

Germination (minimum)                                                                              70%                       70%

Moisture (maximum)                                                                                  8.0%                      8.0%

For vapour-proof containers (maximum)                                                    6.0%                      6.0%

* Objectionable weed is the same as given at IV. B. above.