potato biology and biotechnology

Bradshaw Scottish Crop Research Institute, Invergowrie, Dundee DD2 5DA, United Kingdom Glen J.. Bryan Scottish Crop Research Institute, Invergowrie, Dundee DD2 5DA, Scotland, United King

Elsevier AMS Prelims-N51018 Job code: PBBA 2-5-2007 12:33 p.m Page:i Trimsize:165×240 MM

POTATO BIOLOGY AND BIOTECHNOLOGY

Cover images:

The images are credited to the Scottish Crop Research Institute We are grateful for the

use of the photographs they provided

Elsevier AMS Prelims-N51018 Job code: PBBA 2-5-2007 12:33 p.m Page:iii Trimsize:165×240 MM

POTATO BIOLOGY AND

Laboratory of Plant Physiology

Wageningen University and Research Centre

Amsterdam – Boston – Heidelberg – London – New York – Oxford

Paris – San Diego – San Francisco – Singapore – Sydney – Tokyo

The Boulevard, Langford Lane, Kidlington, Oxford OX5 1GB, UK

Radarweg 29, PO Box 211, 1000 AE Amsterdam, The Netherlands

First edition 2007

Copyright © 2007 Elsevier Ltd All rights reserved

No part of this publication may be reproduced, stored in a retrieval system

or transmitted in any form or by any means electronic, mechanical, photocopying,

recording or otherwise without the prior written permission of the publisher

Permissions may be sought directly from Elsevier’s Science & Technology Rights

Department in Oxford, UK: phone ( +44) (0) 1865 843830; fax (+44) (0) 1865 853333;

email: permissions@elsevier.com Alternatively you can submit your request online by

visiting the Elsevier web site at http://elsevier.com/locate/permissions, and selecting

Obtaining permission to use Elsevier material

Notice

No responsibility is assumed by the publisher for any injury and/or damage to persons

or property as a matter of products liability, negligence or otherwise, or from any use

or operation of any methods, products, instructions or ideas contained in the material

herein Because of rapid advances in the medical sciences, in particular, independent

verification of diagnoses and drug dosages should be made

British Library Cataloguing in Publication Data

A catalogue record for this book is available from the British Library

Library of Congress Cataloging-in-Publication Data

A catalog record for this book is available from the Library of Congress

ISBN-13: 978-0-444-51018-1

For information on all Elsevier publications

visit our website at books.elsevier.com

Printed and bound in Italy

Elsevier AMS Prelims-N51018 Job code: PBBA 2-5-2007 12:33 p.m Page:v Trimsize:165×240 MM

Preface

The potato is the fourth most important food crop in the world after wheat, maize and rice

with 311 million tonnes produced from 19 million hectares at an average fresh weight

yield of 16.4 t/ha in 2003 (FAO statistics), but with a huge range from 2 to 44 t/ha by

country As well as being a staple food the potato is grown as a vegetable for table

use, is processed into French fries and chips (crisps) and is used for dried products and

starch production Processing is the fastest growing sector of the world potato economy,

and today, processors are building factories in countries where the potato is primarily

grown as a staple food In some countries, the potato is still fed to animals but this

use is decreasing In many countries in Asia, Africa and Central and South America,

there is a need for increased and stable potato production to meet increasing demands for

food from human population growth during a period of environmental (including climate)

change Potatoes with improved nutritional and health properties are desirable, but the

overriding need is for increased and stable yields to eradicate human hunger and poverty

In those countries where food security has been achieved, the potato industries are trying

to increase potato usage in an economically and environmentally sustainable way The

emphasis is on more yield of saleable product at less cost of production, reduced use

of pesticides and fungicides, better use of water and fertilizers and meeting consumer

demands for healthy convenience foods and novel products These objectives will be met

only through new cultivars, better crop management and utilization of resources, better

post-harvest storage, better control of pests and diseases and a better understanding of the

social, economic and market factors that influence global production and distribution

Today there is a tremendous opportunity to harness recent advances in potato biology

and biotechnology in these endeavours We therefore considered it timely to ask a number

of experts to help us review the current state-of-knowledge in all aspects of the potato

crop, from basic science to production, processing and marketing Therefore, this book

includes a wide variety of chapters, describing potato markets, genetics and genetic

resources, plant growth and development, response to the environment, tuber quality, pests

and diseases, biotechnology and crop management We gave authors as much freedom

as possible over the content and style of their chapters, consistent with the subject matter

forming a comprehensive and coherent book without unnecessary duplication We did

our best to help authors make their contributions as readable and free from errors as is

possible in a human enterprise The idea to compile such a comprehensive volume was

put forward and initiated by our colleagues Howard Davies and Roberto Viola We are

indebted to them and to many other colleagues for their support, especially Philip Smith

for his proof reading, and to the publishers for their advice and encouragement

We hope that the finished product will be of value not only to potato biologists but also

to all those people throughout the world interested in ensuring that the potato continues

to make a major contribution to the feeding of humankind

Dick VreugdenhilJohn BradshawChristiane GebhardtFrancine GoversDonald K.L MacKerron

Mark A TaylorHeather A Ross

Elsevier AMS Prelims-N51018 Job code: PBBA 2-5-2007 12:33 p.m Page:vii Trimsize:165×240 MM

Acknowledgement

The editors are grateful for the funding of colour prints received from those listed below

The British Potato Council

This page intentionally left blank

Elsevier AMS Prelims-N51018 Job code: PBBA 2-5-2007 12:33 p.m Page:ix Trimsize:165×240 MM

Contents

Kees D van Loon

Elsevier AMS Prelims-N51018 Job code: PBBA 2-5-2007 12:33 p.m Page:xi Trimsize:165×240 MM

Christiane Gebhardt

5.2.4 Cleaved amplified polymorphic sequence, sequencecharacterized amplified region and allele-specific

Herman J van Eck

6.1.3 Morphological and tuber traits discussed in this chapter 92

6.5.5 Growing defects (hollow hearts, growth cracks, second growth,

7 Genetics of Resistance to Pests and Disease 117

Ivan Simko, Shelley Jansky, Sarah Stephenson and David Spooner

7.3.1 Experimental strategies for gene mapping and cloning 130

John E Bradshaw

8.6.1 Sexual and somatic hybridization of S tuberosum with

8.6.2 Molecular-marker-assisted introgression and gene

8.7 Breeding Cultivars at the Tetraploid Level for Clonal Propagation 167

8.7.4 Genetic knowledge and molecular-marker-assisted

Elsevier AMS Prelims-N51018 Job code: PBBA 2-5-2007 12:33 p.m Page:xiii Trimsize:165×240 MM

9.3.3 Use of candidate gene approaches for gene isolation 182

9.7.2 Transgenic approaches for the study of gene function 193

10.3.1 Genomic designation and relationships of diploid potato

10.3.2 Genomic nature and relationships in polyploid potato

10.3.3 Genomic designation and relationships of potato and

non-tuber-bearing species from closely related sections

10.4.1 Fluorescent in situ hybridization-based cytogenetic

Part III Plant Growth and Development 217

11.10 Association Between Development of Above-Ground and

12.5.1 A MADS box protein that regulates axillary branching and

12.5.3 Overexpression of POTH1 negatively regulates

12.5.4 POTH1 protein interacts with seven unique potato BEL

12.5.5 Over-expression of POTH1 and StBEL5 produces an

12.5.6 Mechanism for transcription factors in regulating

Elsevier AMS Prelims-N51018 Job code: PBBA 2-5-2007 12:33 p.m Page:xv Trimsize:165×240 MM

13 Photosynthesis, carbohydrate metabolism and source–sink relations 257

Daniel Hofius and Frederik A.J Börnke

13.4.1 Pathway from the mesophyll to the

13.5.1 Symplastic and apoplastic routes of

13.6.1 Production of hexose phosphates in the

Jeffrey C Suttle

14.5.7 Hormonal regulation of tuber dormancy:

15 Molecular Physiology of the Mineral Nutrition of the Potato 311

Marcel Bucher and Jens Kossmann

Part IV Response to the Environment 331

J Vos and A.J Haverkort

16.2.1 The transport of water in the soil–plant–atmosphere

16.4.2 Effect of drought on plant calcium and13C

A.J Haverkort

17.1.3 Environmental effects on interception of solar

Elsevier AMS Prelims-N51018 Job code: PBBA 2-5-2007 12:33 p.m Page:xvii Trimsize:165×240 MM

18.8 Photosynthesis, Dry Matter Production and Dry Matter Partitioning 384

Ludwig De Temmerman, Karine Vandermeiren and Marcel van Oijen

19.2 Effects of Increased CO2 on Crop Growth and Development 396

19.3 Effects of Increased CO2on Potato Physiology 397

19.5 Interactions Between Yield and Stresses at Elevated CO2 405

19.6.3 Applications of potato models to CO2-related issues:

D.J Donnelly, S.O Prasher and R.M Patel

20.4.1 What is known of salinity tolerance mechanisms in potato? 420

20.6.1 Field and greenhouse evaluations of salinity tolerance in

20.8.1 Salinity-tolerant wild and/or primitive potato species 429

20.8.4 Obtaining salinity tolerance through cell and tissue culture

20.8.5 Obtaining salinity tolerant potato through genetic engineering 433

Michael Storey

Elsevier AMS Prelims-N51018 Job code: PBBA 2-5-2007 12:33 p.m Page:xix Trimsize:165×240 MM

Edward C Lulai

22.3.5 Characteristics of the biopolymers that form suberin 48322.3.6 Suberization: closing layer and wound periderm formation 484

23 Internal Physiological Disorders and Nutritional and Compositional

Joseph R Sowokinos

23.2 General Nature, Incidence and Severity of Internal

23.4 Compositional and Nutritional Changes Affecting End-Use

23.4.3 Factors affecting RS concentration in stored potatoes 517

Mark A Taylor, Gordon J McDougall and Derek Stewart

Part VI Pests and Diseases 541

Edward B Radcliffe and Abdelaziz Lagnaoui

Elsevier AMS Prelims-N51018 Job code: PBBA 2-5-2007 12:33 p.m Page:xxi Trimsize:165×240 MM

Didier Mugniéry and Mark S Phillips

26.1 Potato Cyst Nematodes (Globodera Rostochiensis and Globodera

26.5 The Root Lesion Nematodes (Pratylenchus SPP.) 582

Jan M van der Wolf and Solke H De Boer

Elsevier AMS Prelims-N51018 Job code: PBBA 2-5-2007 12:33 p.m Page:xxiii Trimsize:165×240 MM

28.4.4 Yield loss depending on cultivar resistance and

28.5 Infectious cDNA Clones of Potato Viruses and their use as

28.5.2 Studies on viral infection cycle using infectious cDNAs of

Aad J Termorshuizen

30 Developments in Transgenic Biology and the Genetic Engineering of

Steve Millam

30.3.2 Enhanced or alternative transformation

A.J Conner

31.2 Transgenic Potatoes in the Context of Potato

31.3 The Importance of Field-Testing Transgenic Potatoes 691

Elsevier AMS Prelims-N51018 Job code: PBBA 2-5-2007 12:33 p.m Page:xxv Trimsize:165×240 MM

Philip J White, Ron E Wheatley, John P Hammond and Kefeng Zhang

Elsevier AMS Prelims-N51018 Job code: PBBA 2-5-2007 12:33 p.m Page:xxvii Trimsize:165×240 MM

List of contributors

Eric J Allen Agronomy Centre, Cambridge University Farm,

219b Huntingdon Road, Cambridge CB3 0DL,United Kingdom

Frederik A.J Börnke Department of Biochemistry,

Friedrich-Alexander-Universität, Erlangen-Nürnberg,Staudtstr 5, 91058 Erlangen, Germany

John E Bradshaw Scottish Crop Research Institute, Invergowrie, Dundee

DD2 5DA, United Kingdom

Glen J Bryan Scottish Crop Research Institute, Invergowrie, Dundee

DD2 5DA, Scotland, United Kingdom

Marcel Bucher ETH Zurich, Institute of Plant Sciences,

Plant Biochemistry & Physiology Group,Experimental Station Eschikon 33, CH-8315 Lindau,Switzerland

A.J Conner New Zealand Institute for Crop and Food Research,

Private Bag 4704, Christchurch, New Zealand

Solke H De Boer Canadian Food Inspection Agency, Charlottetown

Laboratory, 93 Mount Edward Road, Charlottetown,C1A 5T1, Canada

Ludwig

De Temmerman

Section Agro-ecochemistry, Veterinary andAgrochemical Research Centre, VAR-CODA-CERVA,Leuvensesteenweg 17, B-3080 Tervuren, Belgium

Danielle J Donnelly Department of Plant Science, Macdonald Campus of

McGill University, 21,111 Lakeshore Rd., Ste Anne deBellevue, QC, H9X 3V9 Canada

David M Firman Agronomy Centre, Cambridge University Farm,

219b Huntingdon Road, Cambridge CB3 0DL,United Kingdom

Tatjana Gavrilenko Plant Genetics, Cytogenetics and Biotechnology, N.I.

Vavilov Institute of Plant Industry (VIR), BolshajaMorskja Street, 42/44, St.-Petersburg 190 000, Russia

Christiane Gebhardt Plant Breeding and Genetics, Max Planck Institute for

Plant Breeding Research, Carl-von-Linné-Weg 10,

50829 Köln, Germany

Francine Govers Laboratory of Phytopathology, Wageningen University,

Binnenhaven 5, 6709 PD Wageningen, TheNetherlands

John P Hammond Warwick HRI, University of Warwick, Wellesbourne,

Warwick CV35 9EF, United Kingdom

David J Hannapel Interdepartmental Plant Physiology Major, 253

Horticulture Hall, Iowa State University, Ames, IA50011-1100, USA

Anton J Haverkort Wageningen University and Research Centre, Plant

Research International, P.O Box 16, 6700 AAWageningen, The Netherlands

Daniel Hofius Institute of Molecular Biology and Physiology,

University of Copenhagen, Øster Farimagsgade 2A,

1353 Copenhagen K, Denmark

Mirjam M.J Jacobs Plant Research International (PRI), Wageningen

University, 6700 AA Wageningen, The Netherlands

Shelley H Jansky USDA-ARS, Department of Horticulture, University of

Wisconsin-Madison, 1575 Linden Drive, Madison, WI

53706, USA

Michael A Kirkman 3, The Coach House, Main Street, Ravenstone LE67

2AS, United Kingdom

Jens Kossmann Director, Institute for Plant Biotechnology, Botany and

Zoology Department, Stellenbosch University, PrivateBag X1, Matieland, South Africa 7602

Abdelaziz Lagnaoui The World Bank, 1818 H Street NW, Washington, DC

20433, USA

Edward C Lulai Sugarbeet & Potato Research Unit, USDA-ARS,

Northern Crop Science Laboratory, 1307 18th St N,Fargo, North Dakota 58105-5677, USA

D.K.L MacKerron (formerly) Scottish Crop Research Institute,

Invergowrie, Dundee DD5 1QX, United Kingdom

Bruce Marshall Scottish Crop Research Institute, Invergowrie, Dundee,

Scotland DD2 5DA, United Kingdom

Elsevier AMS Prelims-N51018 Job code: PBBA 2-5-2007 12:33 p.m Page:xxix Trimsize:165×240 MM

Gordon J McDougall Quality Health and Nutrition Department, Scottish

Crop Research Institute, Invergowrie, Dundee DD25DA, Scotland, United Kingdom

Iain McGregor John Hannah Building, Auchincruive, Ayr KA6 5HW,

United Kingdom

Steve Millam Institute of Molecular Plant Sciences, University of

Edinburgh, Daniel Rutherford Building, KingsBuildings, Edinburgh EH9 3JR, United Kingdom

Didier Mugniéry UMR Bio3P, INRA Domaine de la Motte-au-Vicomte,

BP 32327, 35653 Le Rheu, France

R.M Patel Department of Plant Science, Macdonald Campus of

McGill University, 21,111 Lakeshore Rd., Ste Anne deBellevue, QC, H9X 3V9 Canada

Mark S Phillips Scottish Crop Research Institute, Invergowrie, Dundee,

Scotland DD2 5DA, United Kingdom

S.O Prasher Bioresource Engineering, Macdonald Campus of

McGill University, 21,111 Lakeshore Road, Ste Anne

de Bellevue, QC, H9X 3V9, Canada

Edward B Radcliffe Department of Entomology, 219 Hodson Hall, 1980

Folwell Ave., St Paul, MN 55108-6125, USA

Heather A Ross Quality Health and Nutrition Department, Scottish

Crop Research Institute, Invergowrie, Dundee DD25DA, Scotland, United Kingdom

Sanjeev Kumar Sharma Gene Expression Programme, Scottish Crop Research

Institute, Invergowrie, Dundee DD2 5DA, Scotland,United Kingdom

Research Unit, 1636 East Alisal Streets, Salinas, CA

93905 USA

Joe R Sowokinos Department of Horticultural Science, University of

Minnesota, 311 5th Avenue NE, East Grand Forks,

MN 56721, USA

David M Spooner USDA-ARS, Department of Horticulture, University of

Wisconsin-Madison, 1575 Linden Drive, MadisonWisconsin 53706-1590, USA

Sarah A Stephenson Biological Science Aid, USDA-ARS, Department of

Horticulture, University of Wisconsin-Madison,

1575 Linden Drive, MadisonWisconsin 53706-1590, USA

Derek Stewart Quality Health and Nutrition Department, Scottish

Crop Research Institute, Invergowrie, Dundee DD25DA, Scotland, United Kingdom

Michael Storey British Potato Council, 4300 Nash Court, Oxford

Business Park South, Oxford OX4 2RT,United Kingdom

Paul C Struik Crop and Weed Ecology, Plant Sciences Group,

Wageningen University, Haarweg 333, 6709 RZWageningen, The Netherlands

Jeffrey C Suttle Sugarbeet & Potato Research Unit, USDA-ARS

Northern Crop Science, Laboratory, 1307 18th St

N, Fargo, North Dakota 58105-5677, USA

Mark A Taylor Quality Health and Nutrition Dept., Scottish Crop

Research Institute, Invergowrie, Dundee DD2 5DA,Scotland, United Kingdom

Aad J Termorshuizen Biological Farming Systems, Wageningen

University, Marijkeweg 22, 6709 PG Wageningen,The Netherlands

Jari P.T Valkonen Department of Applied Biology, PO Box 27 (Street

address: Latokartanonkaari 7), FIN-00014, University

Cees D van Loon Oostrandpark 103, 8212 AT Lelystad, The Netherlands

Karine Vandermeiren Department Agro-Ecochemistry, Veterinary and

Agrochemical Research Centre, VAR-CODA-CERVA,Leuvensesteenweg 17, B-3080 Tervuren, Belgium

Marcel van Oijen CEH-Edinburgh, Bush Estate, Pinicuik, EH26 0QB UK

Elsevier AMS Prelims-N51018 Job code: PBBA 2-5-2007 12:33 p.m Page:xxxi Trimsize:165×240 MM

Research Centre, Haarweg 333, 6709 RZ Wageningen,The Netherlands

Dick Vreugdenhil Laboratory of Plant Physiology, Wageningen

University, Arboretumlaan 4, 6703 BD Wageningen,The Netherlands

Ron E Wheatley Environment-Plant Interactions, Scottish Crop Research

Institute, Dundee DD2 5DA, United Kingdom

Philip J White Scottish Crop Research Institute, Invergowrie, Dundee

DD2 5DA, Scotland, United Kingdom

Kefeng Zhang Warwick HRI, University of Warwick, Wellesbourne,

Warwick CV35 9EF, United Kingdom

This page intentionally left blank

Elsevier AMS Ch01-N51018 Job code: PBBA 28-4-2007 9:23 a.m Page:1 Trimsize:165×240 MM

Part I

THE MARKETS

This page intentionally left blank

Elsevier AMS Ch01-N51018 Job code: PBBA 28-4-2007 9:23 a.m Page:3 Trimsize:165×240 MM

Chapter 1

The Fresh Potato Market

Iain McGregor

SAC, Auchincruive, Ayr KA6 5HW, United Kingdom

The potato has arguably revolutionized western society as much as trains, planes and automobiles.

It has been and still is a delicacy, a fast food and a hedge against famine This chapter will review the

market for fresh potatoes largely within the UK, a market that is generally accepted as one of the most

sophisticated potato markets worldwide.

The importance of potatoes within the UK’s agricultural industry and how the cropcompares with other crop enterprises are summarized in Table 1.1 The potato sectorcontributes £482 million in total to food and agricultural output in the UK (Table 1.2)and represents the second most important crop economically after wheat

Potato growing in the UK accounts for an area equivalent to approximately 5% of thecereals’ area Yet its contribution per hectare to the agriculture industry’s revenue is morethan seven times that generated by cereals Potato growing produces a much higher valuecrop per hectare than cereal enterprises, but potato growers face much greater fluctuations

in the level of prices and revenue as mentioned in the section 1.7

According to the calendar-year accounts of the Department of the Environment andRural Affairs (DEFRA) between the mid-1990s and 2005, the value of output fromthe potato sector fell by 41% albeit with significant fluctuations in output during theintervening years and the cereal sector’s receipts fell by a similar amount (43%) over thesame period

Although the registered planted area of potatoes has declined from around 250 000hectares in the early 1960s to 116 400 hectares in 2005 (Fig 1.1), gross production overthe same period has remained relatively constant at around 6 million tonnes (Fig 1.2).The fresh supply chain accounted for around half of this (49%) at 2 958 000 tonnes in2004–05

In 2005, plantings were 4% down, average yields were 2% down and the associatedproduction figure of 5.65 million tonnes represented the lowest production figure recorded

in the UK since 1984 With significant annual variations in value due, among other

Potato Biology and Biotechnology: Advances and Perspectives

D Vreugdenhil (Editor)

© 2007 Elsevier B.V All rights reserved.

Table 1.1 Agricultural output in the UK at current market prices (£ million).

Source: DEFRA, 2006a.

Note: Calendar-year accounts.

Table 1.2 Output from potatoes in the UK, 1999–2005

Source: DEFRA, 2006a.

‘Change’ denotes percentage change between 2004 and 2005.

things, to weather patterns, the underlying trend in average yield has been an increasefrom around 23 tonnes per hectare in 1960 to around 47 tonnes per hectare currently(Fig 1.2) This information, including a breakdown between early and maincrop varieties,

is available in more detail on the web site of the British Potato Council (BPC) athttp://www.potato.org.uk/ The increases in yield have only been possible as a result ofimproved agronomy and crop management, skills which have developed in line withincreasing concentration and specialization among growers in the UK

One may question whether it was as a result of these improved yields that productionhas remained relatively stable despite the significant reduction in the area planted or was

it the rising yields that enabled lower prices and led to the reduction in planted area or,thirdly, was it lower prices that forced the smaller producers from the market

Elsevier AMS Ch01-N51018 Job code: PBBA 28-4-2007 9:23 a.m Page:5 Trimsize:165×240 MM

50 100 150 200 250 300

-1960

Year

5 10 15 20 25 30 35 40

-Planted area Area per grower

Copyright© British Potato Council, 2005.

Total production Net yield/ha Trend of production Trend of net yield

Fig 1.2 Total production of potatoes in Great Britain, 1960–2004 [with permission of British Potato Council (BPC, 2006), Market Information and Statistics] Since 1960, total production in Great Britain has remained

at about 6 million tonnes Annual fluctuations are mainly due to weather – see drought of 1975–76 Yield per hectare has increased steadily compensating for decreasing planted areas.

Grower numbers in Great Britain (GB) have declined dramatically over the last

45 years and continue to decline year on year as the trend in specialization and centration continues To illustrate the scale and significance of the industry shakeout,the author points out that in 1960 there were 76 825 registered growers in the country

con-whereas in 2005 only 3064 (4%) remain The average area planted per grower is nowaround 10 times more than it was back in 1960 (Fig 1.1) In 2005 the average plantingper grower is 38 hectares compared with 3.65 hectares in 1960 The trend in concentration

at production level continues to gain momentum illustrated by the fact that in 1996, 28%

of registered growers were within the 20-hectare-plus size band Almost 10 years later in

2005, 50% of growers are within the over 20-hectare size band (Table 1.3)

Variety choice for the ware market as summarized in Table 1.4 has changed very littleover the years with the top 10 varieties grown accounting for two-thirds (66%) of thetotal national ware crop and with Maris Piper and Estima continuing to dominate themarket in 2005, the former with 20% of the ware area and the latter with 13% MarisPeer and the crisping variety Lady Rosetta swapped places in the 2005 rankings at thirdand fourth places, respectively Marfona moved up a couple of places to the number eight

Table 1.3 Distribution of British Potato Council (BPC)-registered growers by size band (withpermission of BPC, 2006, Market Information and Statistics)

Size band (ha) 2005 2004 2003 2002 2001 2000 1999 1998 1997 1996

Elsevier AMS Ch01-N51018 Job code: PBBA 28-4-2007 9:23 a.m Page:7 Trimsize:165×240 MM

slot probably on the back of continued demand from the domestic buyer and from thepubs and high-street cafes for good-quality baking potatoes

Between 2000 and 2005 there has been a continuous change among the less frequentlyoccurring varieties; for example, Hermes, King Edward (long-standing in the market),Osprey and Harmony all recently achieved higher proportions of the planted area, whereasDésirée, Cara and Maris Bard all declined in popularity The second early Osprey variety

is suited to the pre-pack and general ware market and may end up replacing Cara inthe market Harmony, with 1268 hectares grown for ware in 2005, is an early maincropvariety Whether any of these changes will become progressive and ‘permanent’ remains

to be seen

Market research carried out by the BPC clearly demonstrated that many consumerswant to know more about potato varieties They were in agreement that more should bedone to tell customers about the differing qualities of varieties – a King Edward comparedwith a Maris Piper for example This is an area that will be explored in Section 1.6

1.3 SUPPLY

Total consumption of potatoes in GB is around 6 million tonnes similar to the total GBsupply However, the figure for supply includes 18% waste and 7% seed supply so thatthe net GB supply is around 4.5 million tonnes Processed products are the main import,totalling 1.3 million tonnes raw equivalent with some fresh imports for processing Freshware imports and exports are nearly in balance, with a slight surplus (77 000 tonnes)

on imports The supply chains for fresh and processed potatoes are currently similar involume The volume of potatoes entering the fresh supply chain in GB is estimated bythe BPC to have been 2.96 million tonnes in 2004–05 This represents almost half (49%)

of the total GB consumption figure of 6076 tonnes Figure 1.3 provides a schematicflowchart representing the several market components Table 1.5 gives further details onthe supply and disposal of potatoes in GB and indicates the annual variation betweencomponents The proportions of the planted area that are intended for processing, pre-pack or other fresh variety have been fairly stable between 2000 and 2006, but there is atrend towards increasing fractions that are planted and grown under contract rather thanwithout contract (free-buy) (Table 1.6)

Shoppers in UK spent £81938 million (Table 1.7) on fresh potatoes purchased fromretail outlets in the year ending 18 June 2006 This showed a small reduction (2.2%) inthe previous year’s total consumer outlay, although the quantity of potatoes purchasedwas up by 1.7% because the average price of potatoes in the fresh market was £052 perkilogram, down by 2 pence over the year That change could be explained by the multipleretailers’ continuing quest to drive down prices

Over 80% of fresh potato sales are now made in supermarkets, 70% in the four biggestones, and this gives the multiple retailers massive purchasing power and influence over