P.S. Baenziger.
Triticale breeding continues with an increased emphasis
on forage production and winterhardiness. Currently, our triticales
have a level of winterhardiness that is superior to that of our
winter barley program, but only equal to the moderately winter-hardy
winter wheats. No triticale has the winterhardiness of our best
winter wheats (i.e., Arapahoe or Redland). Though most winter
triticale germplasm tend to be late, our breeding efforts have
concentrated on developing triticales that are earlier than winter
wheat, but not as early as winter barley. The goals are to have
both winter triticale and barley harvested before the main wheat
harvest begins and to cut the forage early in the season to provide
greater flexibility in cropping rotations that require extended
fallow periods or have short-season crops. The superior disease
resistance of triticale compared to wheat was apparent in eastern
Nebraska, where triticale had grain yields of 150 % of those of
winter wheats. In a more normal year, they would have comparable
yields.
Role of RNA-degrading enzymes in regulating gene expression.
Y. Yen and P.S. Baenziger.
Research on wheat RNA-degrading enzymes is ongoing.
Seventeen RNA-degrading enzyme activities of common wheat,
with apparent molecular masses from 42.2 kD to 16.3 kD, were observed
by the RNA-SDS-PAGE assay. To determine their chromosome
locations, all chromosome arms of common wheat, except chromosome
arm 4BS, were assayed in their null condition, using a set of
ditelosomic or nulli-tetrasomic lines of the cultivar Chinese
Spring. Our results showed that the loci for the 22.8 kD and
the 21.2 kD enzymes are located on chromosome arm 2AS, and the
locus for the 21.6 kD enzymes on chromosome arm 2DS. Loci controlling
the 20.1 kD activity were on chromosome arms 2AL, 4BS, 4DS, and
6BS. The locus or loci coding for the gene(s) of the 42.2 kD,
40.9 kD and 39.2 kD were probably located on chromosome arm 5AS,
and their expression in particular and most other RNA-degrading
enzyme activities in general were stimulated when chromosome arm
5AL was missing, indicating an inhibiting locus on 5AL. Our data
suggested that the 31.9 kD, 30.6 kD, and 29.6 kD enzymes possibly
were products of a common precursor, which might be coded by gene(s)
on chromosome arm 6BS, and that the processing is co-regulated
by loci on chromosome arms 2BS, 3DS, 6AL, 6BL, and 7BS. The rest
of the enzyme activities were consistently found in all the lines
tested and, thus, probably are encoded by multiple loci. Alternatively,
their loci may be on chromosome arm 4BS, which we have not assayed
in its null condition.
Variability in wheat streak mosaic virus populations.
J. Petrisko, R.C. French, G. Hein, and P.S. Baenziger.
A study of the population genetics of wheat streak
mosaic virus was completed. Six counties in Nebraska were examined
by collecting 20 plants/field from five fields/county in both
1994 and 1995. Viral coat protein gene and 3'-untranslated
cDNA sequences were amplified by PCR and then grouped according
to AluI restriction patterns. WSMV isolates were extremely
variable; a total of 32 distinct banding patterns were obtained.
The majority of virus isolates (81 %) belonged to one of three
predominant types. Chi square analysis of the banding type frequencies
indicated that as much heterogeneity occurred among virus isolates
from within fields as among fields or even counties. A significant
difference in banding type frequencies occurred between the two
years, largely because of an increase in incidence of one particular
banding type from 38 % in 1994 to 56 % in 1995.
Relationships among WSMV, AgMV, and HoMV Rymoviruses.
R.C. French.
Mite-transmitted potyviruses, of which WSMV
is the type member, have been placed in the Rymovirus genus.
Besides WSMV, two other viruses of wheat belonging to this genus
have been found in the Great Plains. These viruses are the Agropyron
mosaic rymovirus (AgMV) and Hordeum mosaic rymovirus (HoMV).
In order to gain a better understanding of the relationships among
viruses in this genus, and to assess the potential for them to
produce new virus strains via recombination, cDNAs encompassing
a portion of the polymerase and coat protein cistrons of AgMV,
HoMV, and ryegrass mosaic rymovirus (RgMV) were cloned and sequenced.
These three viruses were found to be quite distinct from WSMV
and actually more closely related to the aphid-transmitted
potyviruses. The ability to be transmitted by eriophyid mites
probably evolved independently in at least two distinct potyvirus
lineages. Thus, the phylogenetic status of Rymovirus is
not clear, and as presently constituted, has at least two subgroupings
with WSMV and brome streak mosaic rymoviruses in one group and
AgMV, HoMV, and RgMV in another. Recombination between subgroups
is unlikely.
Occurrence and expression of granule-bound-starch-synthase mutants in hard red winter wheat.
Bob Graybosch, Vern Hansen, and Jim Peterson.
Granule-bound-starch-synthase (GBSS) is the primary
enzyme responsible for the synthesis of amylose in the starch
grains of cereal endosperm cells. In maize, barley, and other
cereals, mutations that eliminate the production of GBSS result
in the formation of amylose-free or `waxy' starch.
Bread wheats, because of their hexaploid genetic system, carry
three genes encoding GBSS. These genes (Wx-A1, Wx-B1,
and Wx-D1) are located on chromosomes 7A, 4A, and 7D, respectively.
A spontaneous waxy mutant, therefore, could arise only by chance
simultaneous mutations at all three loci, an extremely unlikely
event. However, recent developments allow the separation and
identification of the gene products of these three loci. Purification
and separation of GBSS from more than 200 North American hexaploid
wheats have led to the identification of genotypes that carry
null alleles at the Wx-A1 and Wx-B1 loci. Such
genotypes occurred at a frequency of less than 5 %, but were present
in a number of adapted cultivars and advanced breeding lines.
Wheats with single null alleles at either the Wx-A1 or
Wx-B1 locus were grown, along with nonmutant `wild-type'
genotypes, at two different locations in Nebraska in two harvest
years. Amylose content, as measured by the blue polyiodide complex,
was reduced in lines with null alleles by up to 5 % amylose.
Significant environmentally induced variation in amylose content
also was detected.
Genetic stocks carrying null alleles at the Glu-D1 locus.
Bob Graybosch, Jim Peterson, and Paul Mattern.
Five genetic stocks of wheat lacking Glu-D1-encoded,
high-molecular-weight (HMW), glutenin, protein subunits were developed
and released jointly by the USDA-ARS and the University of Nebraska,
Lincoln, NE. HMW-glutenin alleles, especially those arising
from the Glu-D1 locus, contribute significantly to genetic
variation in wheat processing quality. N86L090 (PI591816), an
F3-derived F4 selection, was descended from the cross `Brule/3/Atlas
66/NapHal//Lancota-sib/Aurora'. In addition to the Glu-D1
null-allele, N86L090 carries a 1BL.1RS wheat-rye chromosomal translocation
derived from Aurora. N94L7843 (PI591817), N94L7844 (PI591818),
N94L7845 (PI591819), and N94L7846 (PI591820) are four sister lines
derived from `GKF8261//NapHal/CI13449/3/NE78868'.
All were F3-derived F4 lines, purified by head selections made
in the F6 generation.
Tannin content and wheat grain color.
Bob Graybosch, Vern Hansen, and Jim Peterson.
A biochemical assay for tannin content of wheat grain
was developed and used to investigate tannin content in hard red
and hard white wheats. Tannins were found to occur in white wheat,
albeit at a much lower concentration than that found in red wheats.
On average, red grain displayed twice as much extractable and
measurable tannins than white wheats. Genetic variation in tannin
content also was much higher among red wheats than among white
wheats. The tannin assay would serve as a means to assist in
the classification of hard red and hard white wheats, although
it is too cumbersome for routine use. Tannin content was not
correlated with grain polyphenol oxidase (PPO) activity; red wheats
did have higher average PPO activity, but many white wheats were
isolated with PPO activities that fell within the range of red
wheats. Hence, whereas PPO might be involved in tannin biosynthesis,
its presence does not always result in high tannin levels.
Yield stability of hybrid vs pureline hard winter wheats.
C.J. Peterson; J.M. Moffatt, Agripro Seeds, Inc.; and J.R. Erickson, formerly with HybriTech Seed, Inc.
Hybrid hard winter wheats have shown superior grain
yield potential in regional performance trials. Evidence for
enhanced yield stability, combined with enhanced yield potential,
would facilitate wider acceptance of hybrid wheat by growers.
Hybrid and pureline yield stability and response were compared
in the Southern Regional Performance Nursery (SRPN), 1990 through
1995, and the Agripro, Inc., Standard Variety Trial (SVT), 1993
and 1994. Hybrid wheats examined were developed by HybriTech
Seed, Inc. or Agripro Seeds, Inc.; purelines included advanced
experimental lines and current varieties from throughout the region.
Hybrid and pureline yields were regressed on an environmental
index based on location mean yields for purelines. Hybrids showed
significantly higher mean yields compared with purelines, and
the yield advantage generally increased with increasing environmental
yield potential. The average regression slope was significantly
higher for hybrids (1.09 to 1.12) than for purelines (1.0) in
four of the eight performance trials. Hybrid slopes were not
significantly different in the 1990 through 1993 SRPN. No crossover
in yield response occurred between hybrids and pureline at lower
yield levels. Deviations from regression response were of similar
magnitude for hybrids and purelines. Hybrid wheats show potential
for enhanced mean yield with greater yield response to favorable
environments relative to conventional pureline cultivars.
D.R. Shelton and W.J. Park.
The Nebraska Wheat Quality Lab has a home page on
the World Wide Web: http://ianrwww.unl.edu/ianr/agronomy/wheatlab/index.htm.
The goals and functions of the Lab are presented as well as information
on the Nebraska Wheat Board, the Nebraska Wheat Growers Association,
and U.S. Wheat Associates. Queries about wheat quality have been
received from throughout the world.
Asian rolled noodle quality evaluation.
D.R. Shelton and W.J. Park.
Three sets of wheat samples were investigated for
quality factors related to Asian raw rolled noodle production.
The sets included 40 advanced, experimental, hard white wheat
lines from two different Kansas locations (Sample Set 1); eight
hard white wheat samples grown in California, Colorado, and Idaho
(Sample Set 2); and 10 hard red wheat varieties grown at three
Nebraska locations (Sample Set 3). Effects of variety and growing
location were highly significant for wheat physical tests and
milling properties in both Sample Sets 1 and 3. Relatively high
test and 100-kernel weights and good milling potential were found
in all sample sets. Variety had a significant influence on flour
Chromameter values L (whiteness), a (greenness),
or b (yellowness) for Sample Sets 1 and 3. The influence
of growing location on flour Chromameter L, a, and
b values was significant for Sample Set 1 but not for Sample
Set 3. The trend of more variation in flour a and b
values rather than L values was noted in all sample sets.
The influence of variety and growing location on Mixograph results,
including mixing tolerance score and peak time, were shown to
contribute significantly to their variabilities in Sample Set
3.
Flour samples were processed into raw noodles using
a procedure developed at the Nebraska Wheat Quality Lab. Noodle
color was determined with the Chromameter after production at
times 0, 6, and 12 hours. L (brightness), a (greenness),
or b (yellowness) values at storage times of 0, 6, and
24 hours were influenced by either variety or growing location.
Changes in brightness or green or yellow color from 0 to 6 hours
or to 24 hours were different among varieties and growing locations.
Noodle storage times of 0, 6, and 24 hours had a significant
effect on Chromameter noodle color L, a, and b
values. As storage time increased, noodle color decreased in
brightness and increased in yellowness. Cooking quality characteristics
(cooking time, cooking loss, cooked weight, and cooked volume)
were evaluated. Variety or growing location did not significantly
influence cooking quality parameters for Sample Set 3, partially
because of small variations among varieties or growing locations.
Noodles made from Sample Set 2 had higher weight and volume gains
with less cooking loss and shorter cooking times than those from
Sample Set 3.
A quantitative method also was used to determine
the PPO level of wheat and flour in all three sample sets. Flour
PPO activity had a significant influence on noodle color, resulting
in a decrease in brightness and an increase in yellow color for
Sample Set 3. Quality characteristics such as test weight, 100-kernel
weight, total flour yield, and first reduction flour yield appeared
to influence noodle color as well as color changes during storage.
Noodle color during storage was affected significantly not only
by protein contents of wheat and flour but also by color and ash
contents of wheat and flour. Sheeted noodle color appears to
be a complex trait. Influences of biochemical and physical quality
characteristics of wheat and flour on noodle color varied among
sample sets.
Personnel.
Dr. P.S. Baenziger served for the past two and one-half
years as Interim Head, Department of Agronomy. He returned to
his small grains breeding position with mixed emotions (joy and
happiness) on 6 January, 1996. Dr. Benjamin Moreno, who served
as project leader while Dr. Baenziger was interim head, accepted
a wheat breeding position at North Dakota State University. Masrizal
completed his Ph.D. and returned to Indonesia where he will work
on rice breeding. Ms. Jill Petrisko completed her M.S. and accepted
a position at the National Small Grains Collection in Aberdeen,
Idaho. Mr. Mustafa Erayman, Ahmet Kumlay, and Mehmet Atak joined
the program as graduate students. Dr. Jan Rybczynski joined the
program as a visiting scientist supported by a Fulbright Fellowship
to study triticale and rye tissue culture and transformation.
Publications.
Baenziger PS, Crosby WL, Merrigan KA, and Womack
JE. 1995. Research policy. In: NABC Report 7: Genes
for the Future: Discovery, Ownership, Access. (MacDonald JF ed).
National Agricultural Biotechnology Council, Ithaca, NY. Pp.
29-36.
Baenziger PS, Moreno-Sevilla B, Peterson CJ,
Schmidt JW, Shelton DR, Baltensperger DD, Nelson LA, McVey DV,
Watkins JE, and Hatchett JH. 1995. Registration of `Alliance'
wheat. Crop Sci 35:938.
Budak N, Baenziger PS, and Eskridge KM. 1995. Effect
of replications on measuring wheat plant height. Can J Plant
Sci 75:171-173.
Budak N, Baenziger PS, Eskridge KM, Baltensperger
DD, and Moreno-Sevilla B. 1995. Plant height response of
semidwarf and nonsemidwarf wheats to the environment. Crop Sci
35:447-451.
French R. 1995. Barley yellow dwarf: diagnostic
procedures and reagents In: `Barley Yellow Dwarf:
40 Years of Progress' (D'Arcy CJ and Burnett PA eds).
APS Press, St. Paul, MN. Pp 293-305.
Geske SM, French R, Robertson NL, and Carroll TW.
1996. Purification and coat protein gene sequence of a Montana
RMV-like isolate of barley yellow dwarf virus. Arch Virol
(In press).
Graybosch RA, Peterson CJ, Baenziger PS, and Shelton
DR. 1995. Environmental modification of hard red winter wheat
flour protein composition. J Cereal Sci 22:45-51.
Graybosch RA, Peterson CJ, Shelton DR, and Baenziger
PS. 1996. Genotypic and environmental modification of wheat
flour protein composition in relation to end-use quality. Crop
Sci 36:296-300.
Gustafson VS, Baenziger PS, Wright MS, Stroup WW,
and Yen Y. 1995. Isolated wheat microspore culture. Plant Cell
Tissue and Organ Culture 42:207-213.
Gustafson VD, Baenziger PS, Mitra A, Kaeppler HF,
Papa CM, and Kaeppler SM. 1995. Electroporation of wheat anther
culture-derived embryoids. Cereal Res Commun 23:207-213.
Moreno-Sevilla B, Baenziger PS, Peterson CJ,
Graybosch RA, and McVey DV. 1995. The 1BL/1RS translocation:
agronomic performance of F3-derived lines from a winter wheat
cross. Crop Sci 35:1051-1055.
Moreno-Sevilla B, Baenziger PS, Shelton DR,
Graybosch RA, and Peterson CJ. 1995. Agronomic performance and
end-use quality of 1B vs. 1BL/1RS genotypes derived from
winter wheat `Rawhide'. Crop Sci 35:1607-1612.
Park WJ. 1995. Effect of polyphenol oxidase on
discoloration of rolled noodle products. Ph.D. Dissertation.
Department of Food Science and Technology, University of Nebraska-Lincoln.
214 pp.
Park WJ and Shelton DR. 1995. Investigation of
Asian rolled noodle discoloration relative to agronomic characteristics,
polyphenol oxidase levels, and proximate analyses. Cereal Foods
World 40:648 (Abstract).
Park WJ, Shelton DR, and Caines A. 1995. Development
of a small-scale laboratory noodle fryer for instant fried noodles.
Cereal Foods World 40:667 (Abstract).
Park WJ, Shelton DR, Kachman SD, and Walker AE.
1995. Optimization of temperature and pH for polyphenol oxidase
assay in wheat using response surface methodology (RSM). Cereal
Foods World 40:650 (Abstract).
Park WJ and Shelton DR. 1995. Development of a
small-scale laboratory sheeted noodle dough mixer. The 20th Hard
Red Winter Wheat Workers Conference, Oklahoma City, OK (Abstract).
Peterson CJ and Busch RH. 1995. International Germplasm
Exchange: Status and Future. In: Proc North American
Wheat Workers Workshop (Peterson CJ ed), March 6-8, 1994, Kansas
City, MO. National Wheat Improvement Committee, May, 1995. Pp.
93-112.
Peterson CJ (Ed). 1995. Proceedings of the North
American Wheat Workers Workshop. March 6-8, 1994, Kansas City,
MO. National Wheat Improvement Committee, May, 1995. 214 pages.
Poggi PG, Giunchedi L, French R, Langenberg WG, and
Delogu G. 1995. Polymerase chain reaction identification of
barley yellow mosaic virus and barley mild mosaic virus. Phytopath
Medit 34:114-119.
Salm NS, Rey MEC, and French R. 1996. Molecular
cloning and nucleotide sequencing of the 3'-terminal region
of a South African isolate of ryegrass mosaic virus RNA and in
vitro expression of the coat protein gene. Arch Virol (In press).
Seo YW, Graybosch RA, Peterson CJ, and Shelton DR.
1995. Assessment of enzyme-linked immunoassay of rye secalins
as a tool in the prediction of 1RS wheat quality. Cereal Chem
72:252-254.
Watkins JE, Rutledge SE, and Baenziger PS. 1995.
Virulence patterns of Puccinia recondita f. sp.
tritici in Nebraska during 1992 and 1993. Plant Dis 79:467-470.
Wiess A, Budak N, and Baenziger PS. 1995. Using
transpiration to characterize plant height in winter wheat in
different environments: A simulation study. Can J Plant Sci
75:583-587.
Worrall WD, Marshall DS, Caldwell SP, Peterson CJ,
Baenziger PS, and Schmidt JW. 1995. Registration of Siouxland
89 Wheat. Crop Sci 35:1223.
Yang G, Wehling RL, Zeece MG, Partridge JE, and Shelton
DR. 1995. NOTE: Characterization of hard red winter wheat storage
proteins by two-dimensional electrophoresis, and their correlations
with selected quality parameters. Cereal Chem 72:568-570.
Yen Y, Morris R, and Baenziger PS. 1995. Genome
analysis in wheats: History and current status. In:
Methods of Genome Analysis in Plants: Their Merits and Pitfalls
(Jauhar PP ed). CRC Press, Boca Raton, FL, USA. Pp. 359-373.