REVIEW
Genetic control of Asian rust in soybean
Aliny Simony Ribeiro Æ Jose´ Ubirajara Vieira Moreira Æ
Pedro Henrique Braga Pierozzi Æ Breno Francovig Rachid Æ
Jose´ Francisco Ferraz de Toledo Æ Carlos Alberto Arrabal Arias Æ
Rafael Moreira Soares Æ Claudia Vieira Godoy
Received: 3 February 2006 / Accepted: 6 March 2007 / Published online: 27 March 2007
Ó
Springer Science+Business Media B.V. 2007
Abstract The objective of this study was to
investigate the genetic mechanisms of soybean
resistance to Asian rust (Phakopsora pachyrhizi
Syd. & P. Syd). F2 and F3 generations from 15
diallel crosses involving six soybean cultivars, FT-
2, EMBRAPA 48, BRS 154, BRS 184, BRS 214,
BRS 231, were used to analyze the genetic control
of Asian rust resistance in the soybean parents
tested. Genetic models were fitted to means and
variances of the generations tested in a com-
pletely randomized field experiment with 5,700
hill plots. The experiment was spray-inoculated
twice with an isolate that was first detected during
the 2002/03 season in Mato Grosso (MT) State
and presently prevail in Central Brazil, at a six-
day interval, on borders rows and on the useful
area, respectively, with a 10
4
spores/ml distilled
H
2
O suspension. Assessments were made using a
diagrammatic scale for disease severity at seven
and 39 days after the first detection of Asian rust
in the experiments. Evaluations made in the
second assessment (39 days) discriminated better
between genotypes. Selection at early plant
developmental stages may not result in adult
resistant plants. Cultivar FT-2, which had pre-
sented monogenic resistance to a rust isolated
that prevailed in the first two years of rust
occurrence in Brazil, showed no resistance to
the MT State rust strain used in this experiment,
but eleven crosses showed genetic variability for
resistance in the second assessment. Soybean rust
resistant genes showing predominantly additive
effects are dispersed among parents. Narrow
sense heritability values ranging from 0.42 to
0.74 at the F3 family level in the second assess-
ment suggested that selection of resistant geno-
types is feasible.
Keywords Asian rust Á Disease resistance Á
Genetic analysis Á Genetic inheritance Á
Phakopsora pachyrhizi
Introduction
Asian rust (Phakopsora pachyrhizi Syd & P. Syd)
is a soybean disease initially described in China
that has spread rapidly in several Brazilian
cropping States (Yorinori et al. 2004).
A. S. Ribeiro
Maringa State University, Maringa
´
, PR, Brazil
J. U. V. Moreira Á B. F. Rachid
J. Francisco F. de Toledo (&) Á
C. A. A. Arias Á R. M. Soares Á C. V. Godoy
Genetics and Breeding, Embrapa Soybean, Carlos
Joao Strass Road, Orlando Amaral Access,
P.O. Box 231, 86001-970 Londrina, PR, Brazil
e-mail: toledo@cnpso.embrapa.br
P. H. B. Pierozzi
Londrina State University, Londrina, PR, Brazil
123
Euphytica (2007) 157:15–25
DOI 10.1007/s10681-007-9404-8