Technical aspectsof seed potato

production

Denis Griffin

Seed or Ware?

Why use clean seed?

• Seed quality is one of the most important yielddetermining factors that can be controlled

• Potatoes clonally propagated in soil

• Tubers spread soil borne diseases

• Tubers accumulate seed borne diseases

• Certification scheme established to ensure varietalpurity, generation control and freedom from

disease.

Geographic location advantages and disadvantages

● Northern regions have an

advantage for production ofvirus free seed due to lower

temperatures

● Elevation also limits virusspread by aphids

● The south east of the country

with less rainfall will have lessdisease pressure from both

blight and blackleg

● Southern regions may alsohave an advantage for early

harvest and export.

Land selection

Land selection

● High grade seed area

● Seed potato land scarce

● Large bank of virgin land

● Consider rotation

● Access to irrigation

● Proximity to ware crops

● Fields with a history

● Must be free from PCN

Soil Borne Diseases

Size management for seed

• Target yields 30-35 t ha-1

• Maximise valuable 35-55mm grade

• Plant high seed density 4.2-5 t ha-1

• Break apical dominance, do not sprout seed

• Can reduce nitrogen rate by 40-60 kg ha-1

• Variety dependant

• Early burn down and harvest spreads work load

Size management

0

1

2

3

4

5

6

7

40 60 80 100 120 140 160 180

Days After Planting

LA

I

80 tuber bulking days

Adapted John Burke

Size management

0

1

2

3

4

5

6

7

40 60 80 100 120 140 160 180

Days After Planting

LA

I

80 tuber bulking days

Adapted John Burke

Blackleg

• One of the most problematic diseasesin seed production

• Varieties differ greatly in susceptibility

• Pectobacterium spp most important inIreland

• Dickeyea not established in Ireland

• Important to avoid introduction ofDickeyea

• Rouging necessary to meetcertification standards

• Harvesting conditions, crop dryingand storage are important for control

Gillian Young AFBI

Rhizoctonia

Potato viruses

Aphid transmitted

Persistent

PLRV

Non persistent

PVY

PVA

Contact

PVX

PVS

Virus disease prevalence

34

27.4

41

1311

X

Yo,Yc

Yn

A

S

LR

6

83

35 3

X

Y

Y

A

S

LR

Fiona Hutton and Gerry Doherty

DAFF - 5,635 Samples tested over a 3 yearperiod 2008, 2009, 2010

Teagasc - 2,538 Samples tested over a 3 yearperiod 2008, 2009, 2010

Virus Y

• Two strains known in Ireland

• Virus Yo and Yn

• No Yntn

• Economically most important virus ofseed potatoes and hardest to control

• Persistent virus acquired andtransmitted in less than 30 seconds

• Insecticides prevent population buildup but not infection

• Paraffinic oils sprayed at weeklyintervals may be of use in future

• Roguing only effective controlmeasure

Virus Y secondary symptoms

Yo secondary symptoms Yn secondary symptoms

Storage

• Store hygiene

• Correct labelling

• Segregation of stocks

• Drying and prevention of condensation

• Handling at the correct temperature

• Prevention of dust borne diseases

• Protection from frost

Take home messages

• Land selection

• Size management

• Roguing

• Early burnoff

• Store hygiene

Thank youThank you