Corky Rot

Corky root rot is caused by Pyrenochaeta lycopersici Schn. & Ger. and causes root lesions that form a corky textureprogressively destroyingtherootsystem(Ger-lach and Schneider 1964). Resistance in the form of a recessive gene, py-1, has been integrated into culti-vars from S. peruvianum (Laterrot 1983) and is found on the short arm of chromosome 3 between markers TG40 and CT31 (Doganlar et al. 1998). A new source of resistance controlled by a single dominant gene was reported by Stamova (2004) from a tomato line called Pirelly 38. Field tests with py-1 and the new

Table 13. Resistance genes and markers for the most common tomato fungal diseases

Disease (pathogen)

Resistance gene(s) and/or QTLs

Molecular marker(s)

Chromosome(s)

Source

Reference

Alternaría Stem Canker

Asc

RFLP

3

S. pennellii

van der Biezen et al. 1995;

(Alternaria alternata

Stommel and Zhang 1998;

f. sp. lycopersici)

Mesbah et al. 1999

Anthracnose ripe rot

Several QTLs

RAPD

Various

S. lycopersicum

Stommel and Zhang 1998,2001

(Colletotrichum coccodes)

Blackmold

Several QTLs

naa

2,3,9, 12

S. cheesmaniae

Robert et al. 2001

(Alternaría alternata)

Corky Root

py-1

RFLP

3

S. peruvianum

Doganlar et al. 1998

(Pyrenochaeta lycopersici)

Early Blight

Several QTLs

na

Various

S. lycopersicum,

Foolad et al. 2002; Zhang et al. 2003;

(Alternari solani)

S. habrochaites, S. pimpinellifolium

Foolad and Sharma 2005

Fusarium Crown

Frl

linked to

9

S. peruvianum

Vakalounakis et al. 1997

and Root Rot

Tm22 gene

(Fusarium oxysporiim

f. sp. radidicis-lycopersici)

Fusarium Wilt

1,1-1,1-2,1-2C, 1-3

RFLP

7, 11

S. pimpinellifolium,

Bournival et al. 1990;

(Fusarium oxysporiim

S. pennellii

Sarfattiet al. 1991;

f. sp. lycopersici)

Tanksley and Costello 1991; Ori et al. 1997; Simons et al. 1998

Gray Leafspot

Sm

RFLP

11

S. pimpinellifolium

Behare et al. 1991

(Stemphyllium spp.)

Late Blight

Ph-1, Ph-2, Ph-3,

RFLP

7,9,10 and all

S. pimpinellifolium,

Pierce 1971; Fraryet al. 1998;

(Phytophthora infestans)

Ph-4 and several QTLs

chromosomes

S. habrochaites

Moreau et al. 1998; Chunwongse et al. 2002; Brouwer and St. Clair 2003; Brouwer et al. 2004; Kole et al. 2006

Leaf Mold

Cf-1, Cf-2, Cf-4,

RFLP

1,6

S. habrochaites,

Jones et al 1993; Balint-Kurti et al. 1994;

(Cladosporium fiilvum)

Cf-5, Cf-9

S. pimpinellifolium

Lauge et al. 1998

a Not available a Not available a -Q

T3 G

T3 G

resistance showed py-1 did not resist the pathogen from the infested soil. However, more work needs be to be done on the inheritance of the gene and effectiveness of this new resistance against other isolates.

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