© Benaki Phytopathological Institute
Hellenic Plant Protection Journal
9:
60-65, 2016
DOI 10.1515/hppj-2016-0007
1
Department of Viticulture, Vegetable Crops, Flori-
culture and Plant Protection, Institute of Olive Tree,
Subtropical Crops and Viticulture, N.AG.RE.F., Hellen-
ic Agricultural Organization-DEMETER, PO BOX 2228,
71003, Heraklion, Crete, Greece
2
CFE-Center for Functional Ecology, Department of
Life Sciences, University of Coimbra, P 3000-456
Coimbra, Portugal
* Corresponding author:
Greece has been published for the period
1996-2010 (Tzortzakakis
et al
., 2011); no in-
formation on the presence of virulent pop-
ulations on resistant tomato was includ-
ed. Since 1994, there have been 13 records
of resistance-breaking populations of RKN
fromGreece (Tzortzakakis and Gowen, 1996;
Tzortzakakis
et al.
, 1999; Tzortzakakis
et al.
,
2005; Tzortzakakis and Blok, 2007; Tzort-
zakakis
et al.
, 2008; Tzortzakakis
et al.
, 2014).
The aim of the current study was: a) to
review the published records on the occur-
rence of RKN populations able to reproduce
on resistant tomato in Greece and b) to eval-
uate the reproduction of 20 populations of
RKN, collected randomly from greenhous-
es and outdoor crops of Crete during 2013-
2014, on a resistant tomato and a suscepti-
ble pepper cultivar, and update the existing
information.
Materials and Methods
From June 2013 until December 2014, 20
populations of RKN were collected from
greenhouses and outdoor crops, from vari-
ous areas of Crete. All originated from sus-
SHORT COMMUNICATION
An update on the occurrence of resistance-breaking
populations of root-knot nematodes (
Meloidogyne
spp.) on
resistant
tomato in Greece with six new records from Crete
E.A. Tzortzakakis
1*
, M.-C. Vieira dos Santos
2
and I. Conceição
2
Summary
The available published information on the occurrence of resistance-breaking populations
of root-knot nematodes (
Meloidogyne
spp.) on resistant tomato in Greece is updated. Within the peri-
od 1994-2013, 13 populations (11
M. javanica
and 2
M. incognita
) able to reproduce on resistant tomato
had been recorded in the regions of Crete, Epirus, Thrace, Peloponissos and Macedonia. Ιn the present
study six more resistance-breaking populations, four
M. javanica
and two
M. incognita
, were detect-
ed in the period 2013-2014, all originating from greenhouse vegetables in Crete. Four of these popula-
tions, two
M. javanica
and two
M. incognita
, originated from the region of Ierapetra. This is the first time
that such populations are found in this major area of greenhouse vegetable production of Crete.
Additional keywords
:
Meloidogyne javanica
,
M. incognita , Mi
gene, pathogenicity, pepper, virulence
Root-knot nematodes (RKN),
Meloidogy-
ne
spp., are among the most economical-
ly important nematodes in agriculture with
a broad host range (Karssen and Moens,
2006) and a wide distribution in the Medi-
terranean region (Lamberti, 1981) especially
in greenhouses with vegetables. In tomato,
there are commercially hybrids with resis-
tance to RKN, which is conferred by the
Mi
gene being effective against
M. arenaria, M.
javanica
and
M. incognita
at moderate soil
temperatures (Williamson, 1998). However,
there are several reports concerning viru-
lent populations of these
Meloidogyne
spe-
cies, able to reproduce on resistant tomato
cultivars, occurring either naturally (William-
son, 1998) or after repeated selection on to-
mato plants with the
Mi
gene (Castagnone-
Sereno
et al
., 1994).
A review on the occurrence of RKN in
