Doubled haploid populations of CD87/Katepwa, Cranbrook/Halberd, and
Sunco/Tasman were assessed for seedling response to stem rust and stripe
rust. The CD87/Katepwa population was also screened as adult plants in the
field against stripe rust. The respective parents differed in presence or
absence of various stem rust and stripe rust resistance genes. At least 4
resistance loci controlled adult plant resistance to stripe rust in the
CD87/Katepwa population, and based on quantitative trait loci mapping
results, two of these were contributed by CD87. Pedigree information indicated
that these regions correspond to durable adult plant stripe rust resistance
genes Yr18 and Yr29.
Yr29 was mapped to the distal region of chromosome 1BL.
The third gene, contributed by Katepwa, YrKat, was
located in chromosome arm 2DS. Sr30 mapped distal to
markers abg3 and P36/M61-170 in chromosome arm 5DL. Genes
Yr7 and Pbc (completely linked
with durable stem rust resistance gene Sr2) showed close
associations with markers in chromosome arms 2BL and 3BS, respectively. A
distally located genomic region in chromosome 6AS also affected the expression
of Pbc. The temperature-sensitive stripe rust resistance
gene, YrCK, carried by Sunco showed monogenic
inheritance and was located in chromosome arm 2DS. Several markers showed
complete association with Triticum timopheevi derived
stem rust resistance gene Sr36. Microsatellite markers
stm773 and gwm271A were validated on a set of wheat genotypes and were found
to be diagnostic for the detection of Sr36.
TheSr36-linked Xstm773 allele
showed better amplification than the Sr36-linked
Xgwm271A allele. These markers could be used for marker
assisted identification of Sr36 in breeding populations.
Powdery mildew is an important disease in most of the wheat production areas of the world. The resistance gene Pm21 (6AL/6VS trans‐location) derived from Haynaldia villosa confers resistance to all available isolates of Erysiphe (Blumeria) graminis f. sp. tritici in China and Europe. The objective of this study was to develop fast and reliable sequence characterized amplified region (SCAR) markers linked to the Pm21 gene. A random amplified polymorphic DNA (RAPD) marker for Pm21, OPH171400, was converted to SCAR markers after sequencing the two ends of the polymorphic DNA fragment. Two SCAR markers, SCAR1265 and SCAR1400, were developed to detect the Pm21 gene in different genetic backgrounds. The specific SCAR1265 marker enable large‐scale accurate screening for the presence/absence of Pm21 allele.
Five sets of markers were assessed for their usefulness in breeding, two
linked to wheat stem rust gene Sr2, several markers
linked to a chromosome segment conferring
Yr17/Lr37/Sr38 resistance, two reported markers
for the linked genes Lr35 andSr39,
one for Lr28, and one linked to flour colour. The gene
for Sr2 confers adult plant resistance to stem rust
(Puccinia graminis f.sp. tritici)
and was originally transferred to bread wheat from the tetraploid emmer
(‘Yaroslav’) to the cultivars Hope and H-44. The gene is located
on the short arm of chromosome 3B and confers a durable adult plant resistance
to stem rust usually expressed only in the field. The chromosome segment
carrying the Lr37, Sr38,
Yr17 resistance genes is located on 2AS and was
originally introduced into wheat through an
Aegilops ventricosa
Triticum persicum cross, followed by a cross to the
cultivar Marne (VPM1). The flour colour quantitative trait locus was
originally described in a Yarralinka Schomburg cross and is located on
chromosome 7A. The primers as originally developed required optimisation for
more routine use in a breeding program.
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