FINLAY DALE, JAMES HUTTON INSTITUTE International Storage Conference Sponsored by Certis, 13 February 2014
JHI Potato R&D Pests and Pathogens Late blight Powdery scab (Spongospora) Blackleg (Pectobacterium) Viruses (PVY, PLRV, TRV) Nematodes Quality Flavour Texture Nutritional enhancement (e.g. carotenoids) Anti-nutritionals e.g. acrylamide Storage and sprouting Genetics Gene discovery Development and application of molecular markers Maintenance, characterisation and utilization of genetic resources (e.g. Commonwealth Potato Collection) Genetic enhancement through GM Potato genome sequencing Pre-breeding and commercial breeding Environment Stress tolerance Adaptability to climate change Water and nutrient efficiency (N&P) Environmental impact assessment of new technologies e.g. GM
Approximately half the crop sold off-the-field as fresh produce for immediate use, whilst the rest is stored for periods ranging from a few weeks up to 10 months. Crop destined for pre-pack sales, especially through the major supermarkets, tends to be cold stored using refrigerated stores at temperatures typically in the range 2.5-3.5 C. Minimise development of skin blemish diseases and sprouting. Crops for chipping / crisping are stored at temp.s typically within the range 8-11 C. These higher temperatures minimise the build-up of reducing sugars (glucose and fructose), which cause potatoes to produce dark-coloured chips or crisps after frying. Crops stored at these temperatures for periods longer than a few weeks normally require chemical sprout suppression. 3.5 and 4 million tonnes stored/annum Total costs vary from c. 20 per tonne for short duration, bulk stores for the processed market - to c. 54 per tonne for nine months refrigerated box storage with 15% outgrades going into pre-packing.
Dormancy description No. varieties Very Poor 10 V. poor to Poor 31 Poor 74 Poor to Moderate 64 Moderate 139 Moderate to Good 80 Good 148 Good to Very Good 32 Very Good 24 160 140 120 100 80 60 40 20 0 No. Varieties according to dormancy Series1
<<>> Breeding for Storage Dormancy period: described as long or very long 168 from 981 varieties. 168 varieties found << < 1-100 > >> Ackersegen Bildstar DH 81 7 1463 Hanne Activa BL 81 2 259 DH 84 13 589 Hansa Afra Bodenkraft DH 84 14 780 Hermes Agria Bonita DH 84 22 2076 Hessenkrone Aiko Brenda DH 84 9 162 Hilta Akkord Britta (1980) Diana (NLD) Humalda Alpha Carlita Dinia Ibis Alwara Carrick Domina Ida AM 66 42 Caspar Donella Ilse AM 71 1578 Certa Dorett Indira AM 76 1227 Certo Doris Iris AM 81 940 Champion Draga (1970) Jessica AM 82 137 Ciklamen Elena Karnico AM 83 307 Cilena Elles Karsta Amalia Cinja Eroica Katja Amyl Clarissa Escort Kerpondy Angela Claudia Esta Lajana Arnika (1988) Claustar Exodus Libertas Atlanta (1981) Combi Fortuna (1981) Lori Atlanta (1990) Cosima Fox Lotte Aula Culpa Freia Lucia Barbara Datura Grandifolia Luna (1982) Benol Delcora Granit Mandy Berolina Delica Granola Marco Bettina Deodara Gusto Mazur 168 varieties found Melo Reine Laure Tarago Miriam Remarka Tarpan Miss Malina Renska Tella Monza Rex Tempora Natalie Roeslau Terrina Nena Romano Thomana Nora Rosa (1935) Thynia Nordlicht Rosine Titana Octavia Roxy Toccata Olga Russet Burbank Tomensa Optima Salami Ulme Pamir (1989) Sandra Ute Panda Saturna Vakon Pavo Semena VE 8044 Pentland Javelin SH 82 25 41 Vineta (1972) Pimpernel Sigma Wachtel Pink Fir Apple Solara Warta Pinki Solta Wega (1978) Pino Pomorski Puntila Quarta Sovereign Stania Star Stemster Quinta Switez Ragna TA 11 605 Regale Tanja
<<>> Breeding for Storage Dormancy period: GB Plantings by Variety 2013, top 10 UK varieties by area Variety Hectares 2013 Dormancy description Maris Piper 18,643 Medium [9] Medium to long [13] Markies 6,748 Good dormancy Maris Peer 6,638 Short to medium [13] Lady Rosetta 6,001 Medium to long [9] Long [13, 19] Estima 4,443 Medium to long [9] Long [13, 19] Melody 4,116 Medium to long Harmony 3,886 long natural dormancy Marfona 3,568 Medium to long Hermes 3,161 Long to very long [9] King Edward 3,011 Medium [13] Medium to long [9]
Dormancy in potato Dormancy major problem in potato storage, limits for CIPC use under review in EU Low temperature storage negative effect on tuber quality expensive Common mechanisms in bud dormancy? Genetic, genomic, transgenic resources well-developed in potato Reducing energy use and wastage by improving ethylene control of potato sprouting
Dormancy an important part of the tuber life-cycle Ethylene Reducing sugars Acrylamide Sprouting/dormancy
The length of the dormancy period is under environmental, physiological and hormonal control. Sucrose availability is prerequisite for bud break. In the absence of sucrose, no bud break occurs. Sucrose is likely to serve as a nutrient and signal molecule at the same time. The mode of sucrose sensing most likely involves trehalose-6-phosphate and SnRK1 signalling networks. Once physiological competence is achieved, sprouting is controlled by the level of phytohormones. Two phytohormones: ABA and ethylene, are supposed to suppress tuber sprouting. The exact role of ethylene remains to be elucidated. Cytokinins and gibberellins are required for bud break and sprout growth, respectively. Sonnewald & Sonnewald. Regulation of potato tuber sprouting. Planta (2014) 239:27 38
No ethylene plus ethylene
Sprout Length (mm) Breeding for Storage Inspection 3 Sprout data response to ethylene Negative effect of ethylene Poor response to ethylene Respond well to ethylene Good response to ethylene - Clone Number Red - ethylene Blue - air
Inspection 3 Sprout data response to ethylene Ethylene response associated SNP maps to chr 3 to same scaffolds as microarray genes from bulking experiment Initial inspection reveals potential causative genes auxin response factors, Rb etc, in same scaffold as SNP
Fry colour (4 C) on a 1 (dark) to 9 (pale) scale 70 60 50 40 30 20 Clones Stirling 12601ab1 10 0 2.5 3 3.5 4 4.5 5 5.5 6 6.5 7 Fry colour 1 poor to 9 very good Normal distribution with 79% of variation genetic. Highly heritable trait but no genes of large effect. A low frequency of clones as good as the better parent. More than 69 genes known to be involved.
Offspring on mid-parent regression 15 15 diallel set of crosses: compare parents (mid-parent values) and their offspring (full-sibs). Slope of regression line is measure of narrow -sense heritability.
micrograms acrylamide/kg Breeding for Storage Reducing sugars are important determinant of acrylamide formation in potato products Use cultivars of potatoes that have low levels of reducing sugars Control storage of raw materials (esp. potatoes) 1400 1200 1000 800 600 400 200 0 Klondike Rose y = 0.0745x + 198.61 R 2 = 0.9215 0 2500 5000 7500 10000 12500 15000 17500 glucose + fructose (mg/kg) From Amrein et al. (2003)
micrograms acrylamide/kg French fries micrograms acrylamide/kg French fries Breeding for Storage CONTROL OF SURFACE BROWNING POTATO PRODUCTS Acrylamide levels increased with degree of browning Brown colour as measured by L and a values correlated highly with acrylamide levels 45 µg/kg 76 µg/kg 262 µg/kg 516 µg/kg 866 µg/kg 1512 µg/kg 10000 1000 R 2 = 0.8551 10000 R 2 = 0.8558 1000 100 100 10 45 55 65 75 "L" value 10 5 10 15 20 "a" value
micrograms acrylamide/kg Breeding for Storage Potato Storage Conditions Two cultivars of potatoes Russet Klondike Rose Storage Conditions Room temperature (22-26 o C) Refrigerated storage (6-8 o C) 0 to 4 weeks Klondike Rose Prepared French fries from stored potatoes 180 o C, 3 min Corn oil Acrylamide levels greatest in French fries made from refrigerated potatoes 1400 1200 1000 800 600 400 200 0 Room Temperature (22-26 C) Refrigerated Storage (6-8 C) Day 0 Day 1 Day 7 Day 14 Day 21 Day 28
Acrylamide Controls & parents Lower levels High levels
06H1 diploid population - sprouting Segregates for resistance to Late blight, PVY, PVS, powdery scab, Pectobacterium. Genetic map with ~2500 mapped markers (submitted to TAG) Population segregates for sprouting/dormancy
06H1 linkage map Dense genetic map Anchored to potato genome high level of collinearity Prashar et al. TAG (submitted)
Sprout data collected at JHI 2009-2011 Data scored on 1-9 scale Scores highly correlated Vanessa Young & Karen McLean
Are sprout data relevant to dormancy break? Slow sprout growth at 18 5 spt7_18c 4 3 2 Early sprouters at 4 Data suggest it may be possible to separate dormancy break from sprout growth 1 7.00 7.25 7.50 7.75 8.00 8.25 8.50 8.75 9.00 spt1_4c
Tuber dormancy break and sprout growth 10 9 8 7 6 22 20 18 16 14 12 5 4 Chromosome 3-2009 3 6 0 10 20 30 40 50 60 70 80 Use map, microarray data and genome to identify candidate genes 5 genes being assessed for polymorphism & expression levels 10 8 Karen McLean, Vanessa Young
Sample of other traits considered by potato breeders Disease and pest resistance Late blight - tuber and foliage Common viruses, PVX, PVY, PLRV Cyst nematodes, rostochiensis & pallida Common scab Gangrene Wart Skinspot Powdery scab Spraing (tobacco rattle virus) Soft rot Dry rot Other traits Plus many other (>50) quality & agronomic traits Sugars & acrylamide are two of many important storage traits
Thank you Wish to acknowledge discussions, input and research of colleagues at James Hutton Institute who have contributed to presentation