A Database for Triticeae and Avena
THE UNIVERSITY OF SYDNEY
PBI Cobbitty and Department of Crop Sciences, Private Bag
11, Camden, NSW, 2570; and Sydney, 2006, Australia.
F. Afshari, H.S. Bariana, J. Bell, G.N. Brown, K.S. Gosal,
S. Haque, R.A. McIntosh, H. Miah, R.F. Park, C.R. Wellings, and
The 1999 wheat crop in Australia was one of the largest on
record, despite drought conditions in South Australia. The main
problems were failure to reach adequate protein levels for prime
hard segregation, the usual spate of frosting and sprouting, higher
than usual levels of black point, and a leaf rust epidemic in
A leaf rust epidemic in Western Australia caused losses of
about A$20 M. This epidemic involved susceptible varieties, and
new pathotypes were not involved. In Eastern Australia, considerable
rusting of long-season wheats was caused by mutant pathotypes
virulent for Lr17b (present in the Australian cultivar
Harrier, as well as Norin 10, Brevor 14, and several European
wheats and their derivatives) and Lr13. In New South Wales
and Queensland, the Lr26-virulent pathotype 1041,2,3,(6),(7),9,11
A localized stem rust epidemic in Western Australia occurred
on certain susceptible wheats and the cultivar Westonia, which
has Sr9g. This epidemic was caused mainly by the 'old'
pathotype 34-2,7 which is virulent for Sr9g.
Wheat stripe rust occurred in very low levels in Eastern Australia,
and reports of concern were limited to a few early flowering fields
in Queensland, prior to increases in spring temperatures. Despite
this, two isolates of cultures virulent for Yr17 (VPM1),
designated 104 E137A- Yr17+, are quite distinctive from
the Yr17 pathotype occurring in New Zealand (234 E139A-
Yr17+). Several Australian wheats carry Yr17, and
at least some may be too susceptible to the new pathotype for
continued production; others should have additional adult plant
The new barley grass stripe rust first identified in 1998 continued
to spread throughout most of Eastern Australia. A group of related
barleys appear to be moderately susceptible to this rust, and
its potential as a barley pathogen must now be addressed. We
do not see it as an immediate threat to wheat.
Seedling-resistance genes derived from the Carstens V and Spaldings
Prolific stripe rust differentials were located on chromosomes
2A and 2B, respectively. Both the Spaldings Prolific gene and
Yr27 (Selkirk gene) show close repulsion linkage with Lr13.
Collaborative studies with researchers in Canada have shown that
a stripe rust-resistance gene derived from T. vavilovii
is Yr10. In this stock, Yr10 is associated closely
with a unique gliadin allele.
More than 30,000 lines were tested as seedlings and/or in field
tests for all Australian breeding groups. Two generations of
backcrossing to a wide range of breeding lines were achieved.
THE UNIVERSITY OF SYDNEY
IA Watson Wheat Research Centre, Narrabri, 2390, NSW Australia.
K. Mrva and Daryl Mares.
Some of the Veery lines (CIMMYT) used in breeding programs
in Australia are prone to LMA; that is they have unacceptably
high levels of alpha-amylase (low falling number) in harvest-ripe
grain in the absence of preharvest sprouting. Veery 1, Veery
5, and Veery 7 samples from trials in 1999 had falling numbers
less than 260 sec, whereas the other Veery lines and locally adapted
cultivars had falling numbers between 350 and 480 sec (Table 1).
These results were consistent with previous observations suggesting
that Veery 1, 5, and 7 were similar to genotypes such as Spica,
Mentana, and Lerma 52, which have low falling numbers over a wide
range of environments. These lines contrast with another set
of LMA-prone genotypes that produce low falling number only if
exposed to cool temperatures during the mid-phase of grain development.
This set includes Suneca, derived from Spica, and Kennedy, derived
from Veery 5. One explanation for these observations would be
that the other parents in the pedigrees of Suneca and Kennedy
contribute a gene(s) that modifies the expression of LMA.
Sprouting was widespread in New South Wales in 1999 and also
affected crops in Queensland and Western Australia. Black point
also was prevalent and, as in 1998, we established that grains
affected by black point sprouted more readily than sound grains
from the same sample. This observation has important implications
for the development of tolerant genotypes to screen for sprouting
tolerance and sprouting risk assessment.
Crosses between locally adapted cultivars and the white-grained,
sprouting-tolerant genotype AUS1408 have produced two groups of
genotypes that have different levels of sprouting tolerance.
The first group appears to have recovered all the tolerance, or
grain dormancy, of AUS1408 and has maintained consistent performance
in germination and spike-wetting tests over several seasons.
Unfortunately, these lines are susceptible to crown rot and black
point, and further work is underway to determine whether any linkage
exists. The second group has an intermediate and more variable
level of tolerance. Genotypes in this group appear to have lost
one of the two major genes controlling dormancy in AUS1408 but,
nevertheless, provide some measure of protection, particularly
when compared with current Australian commercial cultivars.