Organization of Genes Conferring Resistance to Anthracnose in Common Bean - Translational Genomics for Crop Breeding: Biotic Stress - page 155

sets of bean genotypes to describe pathogenic
variants and different designation codes such
as Greek letters or specific codes. Cultivars
Michelite, Dark Red Kidney, and Perry Mar-
row were typically used to differentiate races
alpha, beta, gamma, Mex I, II, and III (Yerkes
and Teliz 1956); cvs. Imuna, Kaboon, Coco
alacreme, Widusa and Cornell 49242 were
used in differentiation of the isolates PV 6 ,D 10 ,
E 8 b, I4, alpha1, and alpha 5 (Bannerot 1965);
cvs. Dark Red Kidney, Widusa, Kaboon, Miche-
lite, Sanilac, Prelude, and Cornell 49242 were
used in differentiation of the races alpha, alpha-
Brazil, beta, gamma, delta, kappa, lambda, and
epsilon (Tu et al. 1984; Tu 1994). However,
virulence of isolates classified as one of these
races, or pathogenic groups in other bean geno-
types can reveal additional variation (Leakey
and Simbwa-Bunnya 1972). For example, races
alpha and alpha-Brazil differ in the reaction
on

The standardization of a differential set of
common bean cultivars for the purpose of char-
acterizing the pathogenic variability of C. linde-
muthianum and comparison of research results
was first proposed by Drijfhout and Davis
(1989). However, the proposal did not include
a standardized method to name new pathogenic
variants. Pastor-Corrales (1991) suggested a
standardized method to characterize and des-
ignate new races of C. lindemuthianum . Iso-
lates are characterized based on the response to
twelve differential cultivars (Table 9.1), many
of them included in a previous set of differen-
tial cultivars. Races are designated numerically
according to standardized nomenclature system.
A binary value is assigned to each differential
cultivar and an isolate is classified as the sum
of values of all susceptible differential cultivars.
For example, the majority of isolates collected in
northern Spain (Ferreira et al. 2008) attacked the
following cultivars: Michigan Dark Red Kidney
(MDRK, binary value 2), Perry Marrow (binary

cultivar Cornell 49242 (Tu et al. 1984;

Tu 1994).

Table 9.1. Set of twelve differential common bean cultivars, gene pool origin, and binary nomenclature system used to
characterize and name pathogenic variability of Colletotrichum lindemuthianum . Reaction of twelve differential bean
cultivars against nine different isolates of C. lindemuthuanum is shown.

Isolate

Host
Gene
Pool

CL.
RW
2.0

CL.
USA
2.1

CL.
USA
8.1

CL.
CA
1.0

CL.
CR
2.0

CL.
Hond
1.1

Differential
cultivars

Binary
value

CL
124

CL
63

CL
18

Michelite MA 1 S R R S S S S S S

MDRK AND 2 S S S S R R R R R

Perry Marrow AND 4 R S S S R R R R R

Cornell 49242 MA 8 R R R R R S S S S

Widusa AND 16 R R R S R R R S R

Kaboon AND 32 R R S S R R S R R

Mexico 222 MA 64 R R R R S S S R S

PI 207262 MA 128 R R R R R R R S R

TO MA 256 R R R R R R R S R

TU MA 512 R R R R R R R R S

AB136 MA 1024 R R R R R R R S S

G2333 MA 2048 R R R R R R R S S

Race 3 6 38 55 65 73 105 3481 3657

Race Gene Pool Mx AND AND AND MA MA Mx Mx MA

CL, Colletotrichum lindemuthianum ; First 3-isolates from Spain (Ferreira et al. 2008); RW, Rwanda; CA, Canada; CR, Costa
Rica; Hond, Honduras; AND, Andean; MA, Mesoamerican; R, resistant; S, susceptible, Mx Mixed; References: Pastor-Corrales
1991; Balardin et al 1997; Kelly et al 1994; Kelly and Vallejo 2004.