P.O. Box 729, Bay, AR 72411, USA.
June Hancock and Craig Allen.
The mid-South experienced a very warm, dry fall in
1994, allowing farmers to get their fields ready earlier, which
lead to earlier planting of wheat. The winter was also very mild
and warm and lead to a higher level of aphids and Hessian fly.
Barley yellow dwarf virus was very widespread in our area. In
central Arkansas, a field of COKER 9543 was found with Hessian
fly; COKER 9543 is resistant to Biotype E. A sample was taken
and sent to Roger Ratcliffe, Department of Entomology, Purdue
University. The sample was identified as Biotype L. This field
was planted on September 28. We are currently working with Biotype
L resistance, but we have no commercial varieties with this resistance.
In the lower mid-South, a race change in leaf rust
apparently occurred. COKER 9835, which had previously had good
resistance, was showing susceptibility.
In this past year, we released `COKER 9663'
(L900819). COKER 9663 appears to be widely adapted and expresses
good leaf rust resistance. In 2- and 3-year averages, it has lead
our variety testing. The variety has a short vernalization requirement
and good winter hardiness. Registered seed sales are expected
in the fall of 1996 and certified sales in the following fall.
OR Melhoramento de Sementes Ltda, Rua João Battisti, 76
- Passo Fundo, RS, Brazil.
O.S. Rosa and A.C. Rosa.
Brazilian wheat production was 1.7 million tons in
1995, whereas consumption reached 8.5 million tons. The present
higher wheat prices probably will result in an increase of Brazilian
production to 3 million tons in 1996.
Release of OR 1.
The wheat cultivar `OR 1', selected
in Passo Fundo in an F3 bulk received from CIMMYT, was derived
from the cross `PF 83743/5/PF 83182/4/CNT 10*4/Lagoa Vermelha*5/Agatha/3/Londrina*4/Agent//Londrina*3/NYU
BAI/6/Bagula Sib' (CM 104628-0M-20U-51Y-1U-0U).
This cultivar was released for all regions of Parana
state. The recommended growing area for OR 1 includes soils with
or without aluminum and manganese at toxic levels. The yield of
OR 1 was 15 % higher than the mean yield of the checks, considering
the average of all regions where OR 1 was evaluated during 3 years
in official trials. OR 1 has hard grains, good quality (average
of 19 samplesóW 278, stability 10.35, P/L 0.47), good tolerance
to sprouting, and excellent adaptation to temperate and high temperature
regions. The cultivar is short in height, with a tendency to produce
good tillering and many small spikes per area, good fertility,
and very good resistance to lodging.
OR 1 is resistant to all races of Puccinia graminis
tritici found in Brazil, moderately resistant to scab, and
susceptible to powdery mildew and new races of P. recondita.
OR 1 has good tolerance to Septoria sp. and Helminthosphorium
sp. Although susceptible to soilborne mosaic under conventional
tillage, the symptoms and losses were reduced markedly in a no-till
system.
P.O. Box 17164, Bainsvlei, 9338, South Africa.
F. du Toit, S.S. Walters, A. Brummer, and P. Thorpe.
The 1995 wheat season in the Free State province
will be remembered for frost damage in July and again in September
to early maturing cultivars. Continuous rain during harvest time
in November and December resulted in the widespread occurrence
of sprouting and regrowth, which made harvesting of trials extremely
difficult.
Winter wheat program. One
wheat line, `PAN 3349', was released in April,
1995. PAN 3349 is an intermediate, hard red wheat with good test
weight and protein content and also is fairly tolerant to sprouting.
PAN 3349 has stable yields and is widely adapted in the Free State.
Spring wheat program.
Promising spring wheat lines will be submitted for provisional
release in the Western Cape province this year. One of these lines
yielded 5.5 % higher than `Palmiet', which is the
dominant cultivar in this province. Another elite line yielded
4 % higher than Palmiet in the irrigated areas of the North Cape.
Russian wheat aphid. A
number of highly effective resistance genes are in the backcrossing
program. According to our results, intermediate resistant lines
will make it even more difficult for the wheat farmer to make
decisions on application of insecticides. Our aim is to release
only RWA resistant cultivars with high levels of resistance and
yield potentials similar to those of current susceptible cultivars.
PIONEER HI-BRED INTERNATIONAL, INC.
Worldwide Wheat Research: Johnston, IA, USA.
Ian B. Edwards.
In 1995, three new soft red winter wheat varieties
received commercial numbers in the U.S., two varieties were licensed
in Canada, and our first three durum wheat varieties were registered
in Italy. We opened a new wheat station in England in September,
1995, and we field tested our first hybrids in Spain that utilize
a proprietary genetic system. Our first three durum wheat varieties
in Spain will repeat second year registration in 1995-96, because
drought destroyed the 1995 official tests. In Australia, four
spring wheats entered regional government trials in Queensland
and New South Wales.
Personnel:
Dr. Paul Wilson was appointed Station Manager at
our U.K. research facility at Blissworth, near Northampton. The
station will be fully operational by harvest 1996, the initial
support and crosses having come via our operation in France. A
testing and evaluation program has been operative in the U.K.
since 1990-91.
Gregory C. Marshall, William J. Laskar, and Kyle J. Lively.
The 1994-95 season.
Planting conditions were generally favorable in the fall of 1994.
The warm, moist weather that followed planting promoted abundant
fall growth and unusually high levels of foliar disease infection.
Winter damage was minimal, and by spring the wheat crop appeared to have tremendous yield potential. However, disease pressure began to increase as precipitation became frequent and humidity levels remained high from April to early June. Although several diseases, most notably leaf rust, developed, it soon became apparent that Fusarium head scab would have the most negative effect on yields. All of our yield test locations from Missouri to central Ohio had significant scab infections, and only our three northernmost sites were spared. The Fusarium head scab scores of our commercial test entries averaged across eight sites are listed in Table 1. The table illustrates the kind of significant differences observed at all levels of yield testing.
Table 1. Fusarium head scab ratings of commercial
test entries averaged across eight sites.
________________________________________
Cultivar Score Cultivar Score
________________________________________
Ernie 7.5 2552 5.4
XW531 7.0 2540 5.0
Freedom 6.9 XW548 5.0
2571 6.4 2545 4.9
Cardinal 6.4 Madison 4.8
2548 6.3 2737W 4.2
2510 6.1 Clark 4.1
Sawyer 5.6 Grant 3.7
2568 5.4 2555 2.8
________________________________________
LSD 0.66 CV 8.8
________________________________________
scaleó9 no symptoms, 1 severe symptoms.
The field data we collected tend to confirm the results
of our greenhouse inoculation technique, with the association
between field and greenhouse data being the strongest for those
lines with specific sources of resistance.
Varietal development.
All but two yield test locations were harvested. Fusarium head
scab was primarily responsible for dropping our elite test mean
yield 13 % from the previous year to 78.6 bu/acre. Lines with
more tolerance to head scab were favored, as seen by a highly
significant correlation (r = 0.56) of yield and scab score in
our elite test. However, an insignificant and only slight (r =
0.15) correlation occurred between scab score and flowering date
on this same set of material, indicating that all maturities were
affected similarly.
Selection pressure was very high in our breeding
nurseries for Fusarium head scab and leaf rust. Leaf rust was
particularly severe at our southern Indiana nursery and combined
with the scab and lodging to hold selection percentages well below
normal.
New releases. In August
of 1995, two new soft red winter wheat varieties, `2540'
and `2568' (XW535 and XW532, respectively,
in the 1995 UESRWWN), were released. These varieties will be commercially
available in the fall of 1996. 2540 is an awned, medium-maturing
variety, which has very good test weight, excellent tolerance
to soilborne viruses, and outstanding resistance to prevalent
leaf and stem rust races. 2540 has exhibited outstanding yield
performance and holds a 4 bu/acre advantage over 2548. 2568 is
an awned, early-heading variety with an exceptional yield record,
maintaining a 5.6 bu/acre advantage over 2548. In addition, 2568
has excellent test weight and resistance to leaf rust, stem rust,
and the soilborne viruses. Both varieties are adapted to most
of the soft-wheat growing areas in the northern US.