Storage Forum: 1st March 2016

Ethylene: Its potential for use alongside CIPC

Glyn Harper

The Problem

• In the UK most processing potatoes are treated with CIPC to control sprouting during storage.

• There are real concerns that CIPC usage will be restricted. 

• The processing sector is very vulnerable to the changes in CIPC legislation and there is a urgent need to guard against future constraints on CIPC use by developing alternative control strategies.

Potential Alternatives?

Sustainable Arable Link: Reducing energy usage and wastage by improving ethylene control of potato sprouting. 

• Long‐term solution: Marker assisted breeding• Short ‐medium‐term solution: introduction of alternative sprout suppressants

• Short‐term solution: Develop sprout control strategies using ethylene and, if necessary, a combination of other treatments 

Short‐term Solution

• Short‐term solution: Develop sprout control strategies using a combination of ethylene and, if necessary, a combination of other treatments 

• Ethylene is used to control sprouting of fresh marketed potatoes but there are potential problems with its use for processing potatoes principally ethylene induced sugar accumulation.

• There is a genetic range in response to ethylene ‐ with appropriate varietal selection could ethylene be used for processing potatoes?

Materials and Methods

• Characterisation of processing varieties • Storage temperature 9°C• Four times in‐store replication each 25 tubers, in trays, nets within bulk tubers in 1 tonne boxes or within bulk pile• A gradual ethylene ramp imposed from 0 to 10 ppm and thereafter atmosphere maintained at 10 ppm ethylene.

• Assessment at two monthly intervals over six months, for longest length and number of sites of sprouting, and frycolour (French fries/crisps)

0

2

4

6

8

10

12

0 5 10 15 20

Ethy

lene

(pp

m)

Ramp (days)

Effect of Ethylene: Maris Piper

Values below 4 (USDA 1) are commercially acceptable

SBCSR 1 2 3 4 5 6 7

USDA 000 00 0 1 2 3 4

01020304050607080

2 month 4 month 2 month 4 month 6 month

Untreated Ethylene

Spro

ut L

engt

h (m

m)

Sprout Length

1234567

2 month 4 month 2 month 4 month 6 month

Untreated Ethylene

Fry

Col

our S

core

(SB

CSR

) Fry Colour (chips)

Effect of Ethylene: Russet Burbank

Values below 4 (USDA 1) are commercially acceptable

SBCSR 1 2 3 4 5 6 7

USDA 000 00 0 1 2 3 4

0

10

20

30

40

SO1 SO2 SO1 SO2 SO3

Untreated Ethylene

Spro

ut L

engt

h (m

m)

Sprout Length

1234567

SO1 SO2 SO1 SO2 SO3

Untreated Ethylene

Fry

Col

our S

core

(S

BC

SR)

Fry Colour (chips)

Ramos (0) R. Burbank (0)

Markies (00)Innovator (0)

Varietal responses to ethylene treatmentSprout length  (mm) Processing colour 

chip/crisp Sprout length  (mm) Processing colour chip/crisp

VarietyStorage Period (months)

untreated  Ethylene untreated  Ethylene VarietyStorage Period (months)

untreated  Ethylene untreated  Ethylene

Arsenal2 6.2

Markies2 4.4 2 2.1

4 4 4.5 1.6 26 6 5.4 1.7 2.2

Chicago2 6.3 63.9 61.2

Ramos2 1.4 2.2 2.9

4 64.9 63.1 4 5.5 2 2.96 64 62.1 6 2.8 3.4

Fontane2 2.1 2.6

Royal2 3.2 3.3 4

4 2.5 2.8 4 3.3 3.66 3 3.1 6 3.6 3.9

Lady Claire

2 5.6 66.3 62.9R. Burbank

2 0.2 3.3 3.74 66.6 62.1 4 2.5 3.2 3.26 64.2 63.1 6 3 3.8 3.5

Maris Piper

2 3.4 3.6VR808

2 4.2 65.5 61.34 3.4 3.4 4 9.9 68.4 63.26 3.9 3.4 6 65.1 64.4

SBCSR 1 2 3 4 5 6 7

USDA 000 00 0 1 2 3 4

Summary Results

• Ethylene reduces sprouting in all varieties compared with untreated control.

• There is a pronounced varietal response to ethylene with respect to sprout elongation

• Similar results obtained in tubers stored in trays, boxes and bulk

• Ethylene may cause an increase in fry colour in some but not all varieties

Combination ethylene & CIPC treatment

Experimental outlineCharacterisation of varieties:

• Storage temperature 9°C• 4 replicates/variety sampling occasion• Sample tubers netted within 1 tonne boxes of Markies

Treatments:• 10ppm ethylene/9ppm CIPC• 10 ppm ethylene• 9ppm CIPC

• Gradual ethylene ramp imposed from 0 to 10 ppm over 18 days and thereafter atmosphere maintained at 10 ppm ethylene using Restrain system

• Assessment at two monthly intervals over six months, for longest length and number of sites of sprouting, and for fry colour (French fries/crisps)

Effect of combined CIPC and ethylene treatment: Maris Piper

+/- s.d

Values below 4 (USDA 1) are commercially acceptable

Effect of combined CIPC and ethylene treatment: Russet Burbank

+/- s.d

Values below 4 (USDA 1) are commercially acceptable

Varietal responses to CIPC & ethylene treatmentSprout length  (mm) Processing colour chip/crisp 

colour Sprout length  (mm) Processing colour chip/crisp colour

VarietyStorage Period (months)

Ethylene CIPC + Ethylene CIPC Ethylene CIPC +

Ethylene CIPC VarietyStorage Period (months)

Ethylene CIPC + Ethylene CIPC Ethylene CIPC +

Ethylene CIPC

Arsenal2 6.2 1 2.8

Markies2 4.4 3.4 4.4 2.1 1.9 2.1

4 3 6.1 4 4.5 2.4 15.5 2 1.7 26 2.3 6.9 6 5.4 3.1 35.3 2.2 1.8 2.2

Chicago2 6.3 1.3 2.3 61.2 62.6 59.7

Ramos2 1.4 0.5 0.8 2.9 2.1 2.7

4 4.3 9.7 63.1 63.1 61.5 4 5.5 1.6 5.4 2.9 1.8 36 7.2 14.7 62.1 63 61.7 6 5.1 13.4 3.4 2.7 3.8

Fontane2 3.7 5.5 2.6 1.9 2.7

Royal2 3.2 1.7 9.4 4 3.3 3.8

4 5.5 8.1 2.8 2 3.1 4 12.2 45.7 3.6 3.2 3.56 8 17 3.1 3.2 3.9 6 19.1 65.2 3.9 3.6 3.7

Lady Claire

2 5.6 2 8 62.9 64.3 63.8R. Burbank

2 0.2 0.1 0.8 3.7 3.4 3.74 9.3 43.1 62.1 65.3 62.9 4 2.5 0.9 3.8 3.2 3.2 3.36 17.4 43.8 63.1 60.1 60.9 6 3 2.7 22.3 3.5 3.6 3.5

Maris Piper

2 5.5 6.2 3.6 3.6 3.7VR808

2 4.2 1.7 3 61.3 64.5 63.44 5.5 15.8 3.4 3.3 3.4 4 9.9 2.5 5.2 63.2 64 64.46 3.7 38.2 3.4 3.6 3.9 6 4 8.6 64.4 65.6 62.1

Summary results ethylene/ CIPC• Combination treatment of CIPC (total dose 9ppm) and 10ppm ethylene improved control of sprouting in all varieties compared to either suppressant alone.

• Ethylene may affect fry colour even in the presence of CIPC. 

• There were no statistically significant differences in fry colour with ethylene treatments for Markies, Maris Piper or Russet Burbank whereas Fontane, Ramos and Royal were significantly affected. However, fry colour in the latter varieties was still acceptable.

This approach shows great promise for varieties that are inadequately sprout controlled by ethylene alone and which are not adversely fry colour affected by ethylene including Maris Piper. 

1‐MCP Treatment

• 1‐MCP (0, 330, 660, 1000 ppb) applied on arrival (+/‐ 2 days) of crop at SBCSR, at crop intake temperature. Following overnight exhaust, tuber pull down to 9°C at 0.5°C/day. 

• Following 1‐MCP application and pull down to storage temperature of 9°C, a gradual manual ethylene ramp imposed from 0 to 10 ppm, atmosphere maintained at 10 ppm ethylene.

• Assessment at two and four months for sprouting and fry colour with Markies and Russet Burbank (French fry).

• Sugar analysis on tuber cores (NRI)

1- MCPSmartFreshTM

1‐MCP mitigation of ethylene effect on French fry colour

SBCSR 1 2 3 4 5 6 7

USDA 000 00 0 1 2 3 4

0.0000.0040.0080.0120.0160.020

0 330 660 1000 0 330 660 1000

Intake 2 month 4 month%

Fru

ctos

e FW

Sampling occasion and 1-MCP treatment (ppb)

Russet Burbank Fructose

0.0000.0020.0040.0060.0080.0100.012

0 330 660 1000 0 330 660 1000

Intake 2 month 4 month

% F

ruct

ose

FW

Sampling occasion and 1-MCP treatment (ppb)

Markies FructoseSamplingoccasion(months)

1‐MCP(ppb)

SBCSR French fry  score

sd

Markies

Intake ‐ 2.9 0.52

2 months

0 3.2 0.43330 2.7 0.53660 2.6 0.621000 2.6 0.61

4 months

0 3.1 0.52330 2.8 0.81660 2.8 0.741000 2.7 0.82

RussetBurbank

Intake ‐ 2.9 0.45

2 months

0 3.2 0.39330 3.1 0.48660 3.3 0.511000 3.2 0.43

4 months

0 3.4 0.58330 3.2 0.46660 3.3 0.551000 3.3 0.59

Overall Summary• Varieties differ markedly in their response to ethylene.

• Ethylene reduced sprouting compared with untreated control and was practically useful for some varieties

• At 9°C ethylene treatment caused a slight increase in fry colour in some varieties

• A combination of CIPC/ethylene treatment is an effective strategy of sprout control.

• 1‐MCP has no effect on sprouting but may help to reduce the increase in fry colour caused by ethylene treatment.

Current workCharacterisation of varieties

• Storage temperature 9ºC•4 replicates/variety sampling occasion• Sample tubers netted within 1 tonne boxes of Markies

Treatments (3) •10ppm ethylene/9ppm CIPC; 10 ppm ethylene/16ppm CIPC; CIPC (best practice)

• Gradual ethylene ramp imposed from 0 to 10 ppm over 18 days and thereafter atmosphere maintained at 10 ppm ethylene.

• Assessment at two monthly intervals over eight months, for longest length and number of sites of sprouting, and for fry colour (French fries/crisps)

Acknowledgements

• Colleagues at SBCSR• AHDB Potatoes 

• Defra Link Consortium

• Restrain