Downy Mildew Milestones in Grapevine Breeding

Home , Hibernal (grape), Orion (grape), Phoenix (grape), Regent (grape), Rondo (grape)

Needs for new disease resistance

Reinhard Töpfer and Rudolf Eibach

Institute for Grapevine Breeding Geilweilerhof www.jki.bund.de powdery mildew downy mildew Milestones in Grapevine Breeding

Poor quality fungus High quality fungus resistant genotypes resistant varieties

French hybrids

American hybrids classically bred cultivars

rootstocks (in use for grafting to combat phylloxera)

1800 1900 2000 year

powdery phylloxera downy discovery of fungicidal mildew mildew properties of sulphur and copper

www.jki.bund.de Occurrence of Fungicide Resistances (according to HG Hewitt (1998) Fungicides in Crop Protection, modified by Deising et al.)

Class of First Years prior to Pathogen Fungicides occurrence occurrence of of resistance resistance Organic mercury 1964 40 Pyrenophora avenae

Benzimidazole 1970 2 Venturia inaequalis, Botrytis cinerea Phenylamide 1980 2 Phytophthora infestans, Plasmopara viticola Dicarboximide 1982 5 Botrytis cinerea DMIs 1982 4 Blumeria graminis Carboxanilide 1986 14 Ustilago nuda Morpholine 1994 34 Blumeria graminis Strobilurine 1998 2 Blumeria graminis f.sp. tritici Grapevine Resistance Breeding cultivated Vitis vinifera Vitis wild species – High quality – Poor quality – No mildew resistance – High mildew resistance

Repetitive pseudo backcrosses using various V. vinifera cultivars e. g. Vitis amurensis

New cultivars

e.g. `Müller-Thurgau´ – High quality – High mildew resistance

e.g. `Solaris´ (Breeder WBI Freiburg) www.jki.bund.de Resistance Breeding in Germany

1925 beginning of resistance breeding … identification of resistance loci: 1950 Aris, Siegfriedrebe 1950 1990 Phoenix 1990 Orion, Staufer Regent, Sirius, Merzling

Hibernal, Rondo, Prinzipal, Bronner 2000 2000 Johanniter Ren2

Rpv1 Saphira, Solaris 2005 Helios Run1 C.Carbon, C.Carol, C.Cortis, Rpv2 Prior, Monarch, Bolero Rpv3.1, Rpv4 Ren3 Ren1 Allegro Rpv5, Rpv6, Rpv7 2010 Accent, Piroso Villaris, Reberger, Calandro Rpv8, Rpv9, Rpv11,Rpv13 Run2.1, Run2.2 Baron Rpv10,Rpv3.2 Ren4, Ren5 Muscaris, Souvignier gris, Rpv12 Pinotin, Cabernet blanc 2015 2015 Rpv14 Ren6, Ren7, Ren8 Rpv15 (in preparation) Ren9 (in preparation) 2020

www.jki.bund.de Durability of resistances

Plasmopara viticola (downy mildew) 6 dpi

Peressotti et al.(2010) BMC Plant Biol. 10: 147

Rpv3-1 Rpv10 Isolate SL Rpv3-1 Rpv10

QTL Rpv3 disappears Ren3 applying isolate SL Ren3

Bianca → formation of P. viticola races Bianca www.jki.bund.de Classical Boom-and-Bust Cycle

(Form: Mundt et al. 2014, modified; original data from Browning andwww.jki.bund.de Frey 1969) Specific Considerations: Durability of resistance

Riesling Weisser Heunisch x (Vitis vinifera ssp. sylvestris x Traminer) ?

First mentioning: 1435Rüsselsheim: bill for plants Diebach: vines in a vineyard 1464/1465 Trier: plants for cultivation 1490First documented mentioning of a vineyard 1491(“Ruslingwingart”) near Worms. Downy Mildew: Example I

Bacchus Villard blanc Merzling

Rpv10 Severnyi X X X Muscat Ottonel

Rpv3

Gf.Ga-52-42 Solaris X

Rpv3 Rpv10

Rpv10 Gf.2008-059 Rpv3

Rpv3 Rpv10 Rpv3 Rpv10 Rpv3 Rpv10 Rpv3 Rpv10

www.jki.bund.de 11 Variability of Downy Mildew resistance within the whole progeny (Example I)

Müller-Thurgau (1.6) 40 Gf.Ga-52-42 (4.4) Solaris (4.6)

34 30

20 22

carpet

carriers

population

carriersr

carriers

% % % der Population der % 10

sporangia 9

sporangia 8

sporangia

20 20

5 5

Dense >20 6 No 0 1 1 3 5 7 9 Schwander et al. 2011 Downy Mildew: classes of resistance susceptible Downy mildew resistance level resistent

www.jki.bund.de • individual resistance loci: degree of resistance ? • effect of combination ?

Downy Mildew: classes of resistance Downy Mildew: classes of resistance

Downy Mildew: classes of resistance Downy Mildew: classes of resistance Schwander et al 2011

www.jki.bund.de Downy Mildew: Example II Cab. Sauvignon Solaris X

Rpv10

MTP3082-1-42 Cab. Cortis X

Rpv3

Rpv10 Rpv1 Rpv10 Gf.2015-127 Rpv1

Rpv1 Rpv10 Rpv1 Rpv10 Rpv1 Rpv10 Rpv1 Rpv10 www.jki.bund.de 14 Downy Mildew: Example II

Influence of individual resistance loci and their different combinations on degree of resistance

degree degree degree degree fofoforesistance resistance resistance 3

1 -Rpv1,-Rpv1 -Rpv9 +Rpv1,+Rpv1 -Rpv10 -Rpv1,-Rpv1 +Rpv10 +Rpv1,+Rpv1 +Rpv10 -Rpv10 -Rpv10 +Rpv10 +Rpv10

www.jki.bund.de MTP3082-1-42 X Regent Downy Mildew: Example III

Rpv1 Rpv3 Gf.2005-305-119 X Petra

Rpv1 Rpv3 Rpv12 Kishmish Gf.2011-7-128 X vatkana

Rpv12

Rpv1 Rpv3 Gf.2015-72

Rpv12 Rpv12 Rpv12 Rpv12 Rpv12 Rpv12 Rpv12 Rpv12

Rpv1 Rpv3 Rpv1 Rpv3 Rpv1 Rpv3 Rpv1 Rpv3 Rpv1 Rpv3 Rpv1 Rpv3 Rpv1 Rpv3 Rpv1 Rpv3

www.jki.bund.de Downy Mildew: Example III Influence of individual resistance loci and their different combinations on degree of resistance

Resistenz 5 der

Grad

Grad der der Resistenz Grad degree of resistanceof degree

1 -Rpv1,---Rpv1Rpv1Rpv11 - +Rpv1,+Rpv1+Rpv1+Rpv12 - ---Rpv1Rpv1-Rpv1,Rpv1-Rpv1,3 -Rpv1,-Rpv1,---Rpv1Rpv1Rpv14 -- +Rpv1+Rpv1+Rpv1,+Rpv1,5 +Rpv1,+Rpv1,+Rpv1+Rpv16 -- ---Rpv1,Rpv1Rpv1-Rpv1,7 +Rpv1,+Rpv1+Rpv1,8 -Rpv3,--Rpv3.1Rpv3.1Rpv3.1 - Rpv3,---Rpv3.1Rpv3.1Rpv3.1 - +Rpv3,+Rpv3,+Rpv3.1+Rpv3.1+Rpv3.1 -- ---Rpv3,Rpv3.1Rpv3.1Rpv3,Rpv3.1 +Rpv3,+Rpv3,+Rpv3.1+Rpv3.1 -- -Rpv3,-Rpv3,Rpv3.1Rpv3.1 +Rpv3.1+Rpv3.1+Rpv3,+Rpv3, +Rpv3,+Rpv3.1+Rpv3, ---Rpv12Rpv12Rpv12Rpv12 ---Rpv12Rpv12Rpv12 ---Rpv12Rpv12Rpv12Rpv12 +Rpv12+Rpv12+Rpv12 --Rpv12Rpv12 +Rpv12+Rpv12+Rpv12+Rpv12 +Rpv12+Rpv12+Rpv12 +Rpv12+Rpv12+Rpv12

www.jki.bund.de Downy Mildew no resistance locus Leaf disc essays

Rpv1 Rpv3.1 Rpv12

1 resistance locus

Rpv1+Rpv3.1 Rpv1+Rpv12 Rpv3.1+Rpv12

2 resistance loci

Rpv1+Rpv3.1+Rpv12

3 resistance loci

www.jki.bund.de Comparison of different Downy Mildew resistance loci for their individual degree of resistance - Results deduced from different experiments -

4 degree degree ofresistance 3

1 Rpv1 Rpv3.1 Rpv3.2 Rpv10 Rpv12

www.jki.bund.de Aim: combining 3 resistance loci for powdery mildew ( ) and 3 for downy mildew( )

Downy mildew Powdery mildew

Rpv1 Rpv3-1Rpv3-2 Rpv10 Rpv12 Run1 Ren1 Ren3 Ren4

Rpv1 Rpv3-1 Rpv10 Rpv1 Rpv3-2 Rpv12

Run1 Ren1 Run1 Ren3

Ren3 Type of resistance: 3&3 Ren4 1 …………..……..further combinations……………………40 www.jki.bund.de Specific Considerations: Other Diseases showing up e.g. Black Rot

• caused by Guignardia bidwellii (Ellis) (ascomycete) • nativ to North America, introduced in 1885

www.jki.bund.de What could/should be done from a breeding point of view?

• Focus on major pathogens but look also for the next pathogen • Identify new and strong sources of resistance • Combine different resistance loci  ideally 3 loci (mechanisms) • Do not „burn“ resistances  by using stepwise new single resistances • Use a minimum of plant protection  „add a kind of a chemical resistance mechanism“ • Create varieties with different combinations of resistances • Look for adaptation to climate change

 Make a good compromise on the time scale!  We need international research and pre-breeding!