Pre-breeding for Future Challenges in Nordic apples: European canker European canker M. Lateur • A serious disease which affects more than 100 species • Caused by a fungal pathogen, Neonectria ditissima (formerly Nectria galligena), which is able to cross-infect a wide range of hosts Marc Lateur Sporodochia contain Perithecia contain ascospores (genetic conidia (vegetative recombination) reproduction of a fungus) • The fungus uses both (ascospores and conidia) to enter the host • Damages side branches and the main trank • The infection is spred aerially and with rain splash • There are considerable differences among cultivars in susceptibility to canker • Resistance to canker is a highly quantitative trait: information about cultivar performance can be conflicting Methodology: Inoculations: • Wound inoculations of cut shoots, 3 inoculations/shoot, 1000 conidia/ wound, spring, in a climate chamber, 16 C, 70% RH • Wound inoculations of one-year old trees, 3 inoculations/tree, 1000 conidia/wound, fall-winter and spring, in an unheated greenhouse • ’Natural’ infection under high infection pressure, field Assessments: • Colonization rate through measurements of lesions at regular time intervals; comparisons mellan cultivars are based on AUC • Infection percentage. Comparisons mellan cultivars are based on ratio of infected leaf scars to the total amount of leaf scars Comparisons of the results on colonisation rate obtained for cut shoots in Sweden and Norway and on trees in Sweden 45 70 60 Aroma Aroma 40 Aroma 60 Discovery 50 Discovery 35 Discovery 50 30 Elise 40 Elise Elise 40 25 Ingrid Marie Ingrid Marie Karin 30 Schneider 20 30 Katja Katja Katja 15 20 20 Liberty Liberty 10 Liberty 10 10 5 Santana Santana Santana 0 Williams 0 William's 0 William's Pride Pride Pride Time1 Time2 Time3 Time4 Time5 Time6 Time7 a) Cut shoots, Balsgård, 2013 b) Cut shoots, Njos, 2013 c) Trees, Alnarp, 2011-2012 Results Santana, tree, 57 dpi Discovery, tree, 57 dpi Cox Orange, tree, 57 dpi Fall – winter, 2011-2012 Colonisation rate: Balsgård, 2013: Elise>Discovery>Katja,IngridMarie>William’s Pride>Liberty, Santana>Aroma Njos, 2013: William’s Pride>Elise>Karin Schneider>Katja,Liberty>Aroma>Santana>Discovery(?) Trees, Alnarp, 2011-2012 : Katja>Discovery,Ingrid Marie>Elise>William’sPride>Liberty>Santana>Aroma Infection % Trees, Alnarp, 2011-2012: Elise>Katja>Liberty>Ingrid Marie>Santana>William’s Pride (?)>Aroma 45 Aroma Discovery 40 Elise Enterprise Frösåker 35 Golden Delicious Gyllenkroks Astrakan 30 Heta Hornö Ingrid Marie 25 Jonatan Katja 20 Konsta Liberty Linda 15 Prairefire Risäter 10 Rubinola Red Gravensteiner Rödluvan 5 RöT kaneläpple 0 1 2 3 4 5 70 Angold Aroma 60 ARX 49-18 COOP 12 Discovery 50 Eir Elise Elshof 40 Gala Gloster 30 Idunn Julyred Karin Schneider 20 Katja Leiknes Liberty 10 Martaeple Michinoku Nanna 0 Time1 Time Time3 Time4 Time5 Differences in resistance Level among 58 apple cvs. Potted trees, 2011-2012 25 20 15 10 5 0 Infection percentage under ’natural’ inoculations of one year-old trees QPCR procedure • Novel primers from a variable region in the N. ditissima genome were developed at our laboratory • Allows for estimation of the biomass of N. ditissima in the presumably infected tissue, but we were not able to detect the fungus in presumably healthy tissue Test of the QPCR primers for their specificity PCR-products obtained with qPCR primer pairs on the following DNA-samples: 1. N. ditissima grown on apple leaves placed on PDA; 2. Clean culture of N. ditissima grown on PDA; 3. Alternaria solani; 4. In-vitro M26; 5. Infected tissue; 6. Negative control We, who are involved: Larisa Gustavsson, Marjan Ghasemkhani, Anna Zborowska (Alnarp) Hilde Nybom, Jasna Sehic (Balsgård) Dag Roen, Kurab Roen (Njos) Support in statistical analyses: Jan-Eric Englund International projects: ’FruitBreedomics’ (coord. by Francois Laurens, INRA) WP3 ’Identification of QTL for fruit quality and disease resistance’ WP4 ’Exploring of phenotypic and genetic diversity in European apple and peach WUR, Netherlands: Eric van de Weg CRA-W, Belgium: Marc Lateur Plant & Food Lmt, New Zealand: Reiny Scheper, Kerry Everett Thanks! Cox Orange Liberty .