Identification and mapping of quantitative resistance to late
blight (Phytophthora infestans)inSolanum habrochaites
LA1777
Junming Li
•
Lei Liu
•
Yuling Bai
•
Richard Finkers
•
Feng Wang
•
Yongchen Du
•
Yuhong Yang
•
Bingyan Xie
•
Richard G. F. Visser
•
Adriaan W. van Heusden
Received: 19 November 2009 / Accepted: 28 December 2010 / Published online: 19 February 2011
Ó The Author(s) 2011. This article is published with open access at Springerlink.com
Abstract Late blight (Phytophthora infestans) can
have devastating effects on tomato production over
the whole world. Most of the commercial cultivars of
tomato, Solanum lycopersicum, are susceptible.
Qualitative and quantitative resistance has been
described in wild relatives of tomato. In general
qualitative resistance can more easily be overcome by
newly evolved isolates. Screening of three S. habro-
chaites accessions (LA1033, LA2099 and LA1777)
through a whole plant assay showed that accession
LA1777 had a good level of resistance to several
isolates of P. infestans. To explore the potential in
this wild species, an introgression line (IL) popula-
tion of S. habrochaites LA1777 was used to screen
individual chromosome regions of the wild species by
a detached leaf assay. Two major isolates (T
1,2
and
T
1,2,4
) were used and two parameters were measured:
lesion size (LS), and disease incidence (DI). Sub-
stantial variation was observed between the individ-
ual lines. QTLs were identified for LS but not for DI.
The presence of five QTLs derived from LA1777
(Rlbq4a, Rlbq4b, Rlbq7, Rlbq8 and Rlbq12) results in
unambiguous higher levels of resistance. All QTLs
co-localized with previously described QTLs from
S. habrochaites LA2099 except QTL Rlbq4b, which
is therefore a novel QTL.
Keywords Tomato Á Late blight Á Phytophthora
infestans Á Quantitative resistance Á Solanum
habrochaites Á Introgression lines
Introduction
The oomycete Phytophthora infestans (Mont.) de
Bary, the causal agent of late blight, is one of the
most destructive pathogens of potato and tomato.
Late blight causes serious yield and economic losses
especially under favorable conditions for the patho-
gen (wet and cool temperatures) both in the open field
as well as in non-heated greenhouses. The responsi-
ble pathogen is heterothallic and forms oospores with
A1 and A2 mating types and has been found in
different areas of the world (Gotoh et al. 2005). The
co-existence of mating types and the sexual repro-
duction increase the chance of developing resistance
to fungicides such as metalaxyl (Goodwin et al. 1998;
Gotoh et al. 2005). In addition, the spread of the
disease may be also initiated from spores present in
the soil (Widmark et al. 2007). The genetic diversity,
J. Li (&) Á L. Liu Á F. Wang Á Y. Du Á Y. Yang Á B. Xie
Institute of Vegetables and Flowers, Chinese Academy of
Agricultural Sciences, No. 12 Zhongguancun Nandajie,
Haidian District, Beijing 100081, China
e-mail: junmingli@mail.caas.net.cn
J. Li Á Y. Bai Á R. Finkers Á R. G. F. Visser Á
A. W. van Heusden
Graduate School Experimental Plant Sciences,
Wageningen UR Plant Breeding, Wageningen University
and Research Center, PO box 386, 6700 AJ Wageningen,
The Netherlands
123
Euphytica (2011) 179:427–438
DOI 10.1007/s10681-010-0340-7