UNIVERSITY OF KENTUCKY
Wheat Breeding and Genetics, Department of Agronomy, N106 Agricultural
Science Building North, Lexington, KY 40546-0091, USA.
D.A. Van Sanford, C.T. MacKown, and C.S. Swanson.
Production.
The average wheat yield for the 1994-95 season
was 53 bu/acre, down 4 bu/acre from the record yield of the preceding
season. Several factors were responsible for the yield reduction,
including BYDV, leaf rust, and, in central KY, head scab. The
long Indian summer, which prevailed until December, favored aphid
buildup and BYDV infection. Leaf rust levels were higher than
they had been since 1985. Scab levels ranged from zero to sufficiently
high that some farmers abandoned their crop. (Van Sanford)
Chlorate is an analog of nitrate that is used to
nitrate uptake and assimilation in several species. We evaluated
six wheat cultivars, three previously classified as chlorate-tolerant
and three described as chlorate-sensitive, in a seedling
uptake study. One cultivar previously described as chlorate tolerant,
Pioneer Brand 2550, appeared to live up to that classification
in our study. Pioneer 2550 was the only entry that did not show
dry weight and chlorophyll reductions in response to chlorate.
However, in none of the cultivars were tissue nitrate or chlorate
concentrations related to presence or absence of chlorate in the
uptake medium. (MacKown, Van Sanford)
Germplasm and variety release.
`KY 83C-16-2'
soft red winter wheat germplasm was released for its unique combination
of winterhardiness and disease resistance.
Release of `Foster' soft red winter
wheat. The Kentucky Agricultural Experiment
Station announces the release of `Foster' soft
red winter wheat (Triticum aestivum L.). Foster was derived
from a single head selection in the F2 of the three-way cross'
KY 83-60/Tyler//KY 83-75'. KY 83-60 and KY 83-75 were
selections from bulk populations provided by T.M. Starling, formerly
small grains breeder at Virginia Polytechnic Institute and State
University. The pedigree of KY 83-60 is `Coker 65-20/Arthur/4/Chul*8CC//VA
68-22-7/Abe/3/VA 72-54-14'. The pedigree of KY 83-75 is
`Suwon 92/Arthur//Arthur/VA 70-52-2'.
A combination of pedigree and bulk selection methods
was used in subsequent generations. A single F8 progeny plot
was increased in the F9 and F10 generations to produce F11 breeder
seed. Foster was tested in Kentucky from 1992-95 and in
the Uniform Eastern Soft Red Winter Wheat Nursery in 1994 and
1995. Foster was tested as KY 85C-31-6 and was entry 30 in the
1993-94 Uniform Eastern Nursery and entry 12 in the 1994-95
Uniform Eastern Nursery. Foster was released for its excellent
yield potential, broad adaptation, high test weight, excellent
disease resistance, and outstanding milling and baking quality.
Foster is a white-chaffed, awnletted, soft red winter
wheat with midlong spikes and intermediate-size kernels. The
cultivar is of midseason maturity, heading approximately 3 days
earlier than Cardinal. Foster is of intermediate height, equivalent
to Jackson. Winterhardiness of Foster is similar to that of `Verne'.
In 3 years of testing in the seven-location Kentucky state variety
trial, grain yield of Foster was 115 % of Clark, and 103 % of
Northrup King Coker 9803. Foster was tested for 2 years in the
Uniform Eastern Soft Red Winter Wheat Nursery, where it was the
top-yielding entry across 33 locations in 1994, averaging 5,172
kg/ha and the third highest-yielding entry across 28 locations
in 1995, averaging 4,483 kg/ha. The test weight of Foster is
slightly higher than that of Madison. In several years of testing
at the USDA Soft Wheat Quality Lab in Wooster, OH, Foster has
demonstrated excellent milling quality, with high break flour
yield and softness equivalent, similar to those of Cardinal, and
excellent baking quality.
Foster has excellent resistance to powdery mildew
(caused by E. graminis (DC.) f. sp. tritici Em.
Marchal) and Septoria leaf blotch (caused by S. tritici
Roberge ex Desmaz.). Foster has moderate resistance to glume
blotch (caused by Phaeosphaeria nodorum (E. Muller) Hedjaroude)
and to some races of leaf rust (caused by P. recondita
Roberge ex Desmaz. f. sp. tritici Eriks. & E. Henn.).
Foster is moderately susceptible to barley yellow dwarf virus
and is susceptible to all biotypes of the Hessian fly (Mayetiola
destructor (Say)).
The breeding research that generated this cultivar
was supported in part by the Kentucky Small Grain Growers Association
/ Kentucky Small Grain Promotion Council. Exclusive marketing
rights to Foster have been granted to Agripro Seeds, Inc. Seed
classes of Foster will be breeder, foundation, registered, and
certified. Breeder seed will be maintained by the Foundation
Seed Project, Department of Agronomy, University of Kentucky,
Lexington, KY 40546-0091 USA. Application for plant variety
protection (Title V) of Foster will be submitted by the Kentucky
Agricultural Experiment Station.
Personnel changes.
Because of the USDA's decision to close their
Lexington location, Charles MacKown was transferred to a USDA
facility in Durant, OK, after 15 years in Lexington. Bill Pearce
completed his Master's degree and accepted a position with
the corn variety testing program.
Publications.
Van Sanford DA and Utomo H. 1995. Inheritance of tillering in a winter wheat population. Crop Sci 35:1566-1569.
Van Sanford DA, Pearce WL, Swanson CS, Tutt CR, Tomes
LJ, and Hershman DE. 1995. Registration of KY 83C-16-2
wheat germplasm. Crop Sci 3:1719.
Ma YZ, MacKown CT, and Van Sanford DA. 1995. Kernel
mass and assimilate accumulation of wheat: cultivar responses
to 50 % spikelet removal at anthesis. Field Crops Res 42:93-99.
MacKown CT, Van Sanford DA, and Rothwell CG. 1995.
Chlorate tolerance and nitrate uptake and assimilation of wheat.
Agron Abstr p .102.
LOUISIANA STATE UNIVERSITY AGRICULTURAL CENTER
Departments of Agronomy, Plant Pathology and Crop Physiology,
Baton Rouge, LA 70803 USA, and the Northeast Research Station,
Box 438, St. Joseph, LA 71366, USA.
S.A. Harrison, K. Whitehead, and C. Seale (Agronomy Department); K.M. Tubajika, J.S. Russin, and C.A. Clark (Plant Pathology & Crop Physiology Department) and H.J. Mascagni (Northeast Research Station).
Seed transmission of Xanthomonas campestris.
Seed transmission of Xanthomonas campestris pv
translucens (Xct) was evaluated in selected wheat cultivars
in microplot studies. We do not know the frequency of transmission
of Xct through the seed or the amount of disease that must be
present on plants in order to get seed transmission in Louisiana.
We collected seed from tillers that showed disease severity on
flag leaves ranging from 0-90 %.
Xct was detected in seed of susceptible cultivars
Florida 304 and Savannah, from diseased plants inoculated with
a mixture of strain Xct 90-1, Xct 42, and Xct 41. The percentage
of seed infected ranged from 2-23 %. Transmission of the
pathogen into seedlings did not occur in a heat-treated seed lot
when planted in river silt soil. The pathogen was transmitted
to seedlings at rates of 0.2-1.7 % from seed harvested
from diseased plants. (Tubajika, Tillman, Russin, Harrison, and
Clark)
Because most winter wheat cultivars are susceptible
to bacterial leaf streak (Bls), it important to understand how
the pathogen spreads through the field in order to develop approaches
to reduce that spread. Field tests with Terral 101(resistant)and
Florida 304 (susceptible) were established at two locations and
inoculated with a rifampicin-resistant strain of Xct at specific
points. Plants at various distances and different directions
from inoculum sources were monitored for disease. Disease severity
was low. Pathogen and disease were detected at 0.13, 1, 2, 4,
and 6 m distance intervals in Florida and at 0.13, 1, 2, and
4 m in Terral 101, 38-47 days after inoculation. Disease
was observed 7-10 days earlier in Florida 304 than in Terral
101 at both locations. BLS incidence declined with distance from
inoculum source for both cultivars. Direction from the source
had a significant effect on bacterial population and disease incidence
at each location. The pathogen was capable of spreading 36 sq
m from a point source within 103 days in Louisiana. The infection
of new plants is highly dependent upon the proximity to a higher
number of diseased plants. (Tubajika, Russin, Clark, Harrison)