TRUE POTATO SEED (TPS) (Solanum tuberosum L.) HYBRIDS

I. Application and Amplification of General Seed Certification Standards

A. The General Seed Certification Standards are basic and together with the following specific standards 

     constitute the standards for certification of hybrid TPS.

B. The General standards are amplified as follows to apply specifically to the TPS hybrids:

1. Eligibility requirements for certification

(a) The parental seed stock to be eligible for certification shall be from a source such that its identity may be 

     assured and approved by the Certification Agency.

(b) Hybrid seed to be eligible for certification shall be the progeny of two approved parental lines.

2. Classes and sources of seed

(a)  Breeder and Foundation seed classes shall be produced and multiplied from seed potato (seed tubers).

(b)  Foundation class of seed potato shall conform to the same Minimum Seed Certification Standards as 

      specified for certification of seed potato and if required may be increased in two stages namely Foundation 

      stage-I and Foundation Stage-II.

(c)  The certified seed class shall be the hybrid TPS to be planted for any use except seed production.

II. Land requirements

Seed fields offered for certification of TPS hybrids preferably should not be infested with:

- wart (Synchytrium endobioticum (Schilb.) Perc. and or cyst forming nematodes;

- brown rot (Pseudomonas solanacearum (E.F.Sm.). E.F.Sm.or non -cyst forming nematodes within the 

      previous three years;

- common scab (Streptomyces scabies (Thaxt.) Waks. & Henrici).

III. Field Inspection

A minimum of four inspections shall be made as follows:

1. the first inspection shall be made before flowering to verify isolation, extent of disease infection and offtypes 

    in female and male blocks;

2. the second and third inspections shall be made during flowering to verify offtypes, extent of disease infection 

    and efficiency of cross- pollination;

3. the fourth inspection shall be made during harvesting in order to confirm that selfed berries are eliminated 

    and only properly crossed berries are harvested.

IV. Field Standards

A. General requirements

1. Isolation

Seed fields of TPS hybrids for Certified seed class be isolated from the contaminants shown in the column 1 of the Table below by the distances specified in columns 2 of the said Table:

        Contaminants                                                                                   Minimum distance (meters) 

                1                                                                                                                            2     

Fields of other varieties including commercial hybrid of the 

same variety                                                                                                                           50

Fields of the same hybrid (Code designation) not conforming to the

varietal purity requirements for certification                                                                              50

Between blocks of the parental lines of the same hybrid in case 

female and male parents are planted in separate blocks                                                             5

B. Specific requirements

        Factor                                                                                              Maximum permissible limits

                                                                                                                Certified seed stage 

                                                                                                              (for both the parents)   

*Offtypes                                                                                                     0.10%         

** Plants showing symptoms of : 

    - Mild mosaic                                                                                           3.0%

    - Severe mosaic, leaf roll and yellows                                                        1.0%  

** Plants infected by brown rot  (Syn. Bacterial wilt )                                                         

     (Pseudomonas solanacearum) (E.F.Sm.) E.F.Sm.)                             3 plants per Hectare

     *Maximum permitted at and after flowering.

  ** Maximum permitted at final inspection, through the disease mentioned above are not transmitted through 

       TPS but it is essential to maintain a good crop hygiene.    

C.    1.    All certified hybrid TPS lots produced by adopting emasculation or tubing or without emasculation 

               with timely application of pollen from male parent to avoid selfing or through use of Chemical 

               Hybridising Agents' (CHA's) shall be subjected to grow-out test and shall conform to the following 

               minimum genetic purity (Hybridity) requirements:

                    Class                                                                    Genetic purity % (minimum)

                    Certified                                                                             90

        2.    During grow-out test, the offtype plants (other than selfed plants) such as segregants, outcrosses 

               and plants of other varieties should not exceed more than 1.50% out of 10.0% plants ear-marked 

               for selfed plants.            

        3.    The minimum population size of 400 plants shall be maintained in two replicates of 200 each or four 

               of 100 each throughout the test and each plant shall be examined individually. The reject number 

               shall be as follows:

                Class                                                    Minimum genetic                             Reject number

                                                                                purity (%)    

                Certified                                             90.0 (10 in 100)                                        44

V. Seed standards

        Factor                                                                                         Standards for certified class seed

Pure seed (minimum)                                                                                          98.0 %                    

Inert matter (maximum)                                                                                       2.0 %                        

Weed seeds (maximum)                                                                                    10 / kg                      

Germination (minimum)                                                                                      80.0 %                    

Moisture (maximum)                                                                                            8.0 %                     

For vapour-proof containers (maximum)                                                              6.0 %