Original research articles The current strategy to control grapevine downy and powdery mildew relies on chemical treatments. An alternative solution to the use of chemicals is the development of varieties resistant to pathogens. Several genetic factors derived from Vitis species closely related to cultivated grapevine and conferring protection against downy mildew or powdery mildew have already been identified.

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Confirmation and Fine Mapping of the Resistance Locus Ren9 from the Grapevine Cultivar 'Regent'

Grapevine ( Vitis vinifera ssp. vinifera) is a major fruit crop with high economic importance. Due to its susceptibility towards fungal and oomycete pathogens such as Erysiphe necator and Plasmopara viticola, the causal agents of powdery and downy mildew (PM and DM, respectively), grapevine growers annually face a major challenge in coping with shortfalls of yield caused by these diseases.

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Confirmation and Fine Mapping of the Resistance Locus Ren9 from the Grapevine Cultivar 'Regent'

Table 1. Resistance factors to downy and powdery mildew identified in grapevine

Factor	Controlled disease	Origin of resistance	Chromosome	Resistance level	Reference
Rpv1	Downy mildew	V. rotundifolia	12	High	Merdinoglu et al., 2003
Rpv2	Downy mildew	V. rotundifolia	18	Total	Wiedemann-Merdinoglu et al., 2006
Rpv3	Downy mildew	V. rupestris	18	Partial	Bellin et al., 2009; Welter et al., 2007
Rpv4	Downy mildew	American Vitis	4	Weak	Welter et al., 2007
Rpv5	Downy mildew	V. riparia	9	Weak	Marguerit et al., 2009
Rpv6	Downy mildew	V. riparia	12	Weak	Marguerit et al., 2009
Rpv7	Downy mildew	American Vitis	7	Weak	Bellin et al., 2009
Rpv8	Downy mildew	V. amurensis	14	High	Blasi et al., 2011
Rpv9	Downy mildew	V. riparia	7	Weak	Moreira et al., 2011
Rpv10	Downy mildew	V. amurensis	9	High	Schwander et al., 2012
Rpv11	Downy mildew	American Vitis	5	Weak	Fischer et al., 2004
Rpv12	Downy mildew	V. amurensis	14	High	Venuti et al., 2013
Rpv13	Downy mildew	V. riparia	12	Weak	Moreira et al., 2011
Rpv14	Downy mildew	V. cinerea	5	-	Ochssner et al., 2016
Run1	Powdery mildew	V. rotundifolia	12	Total	Pauquet et al., 2001
Run 2.1	Powdery mildew	V. rotundifolia	18	Partial	Riaz et al., 2011
Run 2.2	Powdery mildew	V. rotundifolia	18	Partial	Riaz et al., 2011
Ren1	Powdery mildew	V. vinifera	13	Partial	Hoffmann et al., 2008
Ren2	Powdery mildew	V. cinerea	14	Partial	Dalbó et al., 2000
Ren3	Powdery mildew	American Vitis	15	Partial	Welter et al., 2007
Ren4	Powdery mildew	V. romanetii	18	Partial	Riaz et al., 2011
Ren5	Powdery mildew	V. rotundifolia	14	Total	Blanc et al., 2012
Ren6	Powdery mildew	V. piasezkii	9	Total	Pap et al., 2016
Ren7	Powdery mildew	V. piasezkii	19	Partial	Pap et al., 2016
Ren8	Powdery mildew	American Vitis	18	Partial	Zyprian et al., 2016

Resistance Table