NEBRASKA
UNIVERSITY OF NEBRASKA AND THE USDA-ARS
Department of Agronomy, Lincoln, NE 68583, USA.
The 2000 Nebraska Wheat Crop was estimated at 59,400,000 bu, which represented a 36.0 bu/acre state average yield on 1,650,000 harvested acres. 1,800,000 acres were planted to winter wheat. The crop was much lower than the 1999 crop (86,400,000 bu from 1,800,000 harvested acres) because of severe drought in much of the wheat-growing region and low grain prices forcing reduced input use. Arapahoe continues to be the most popular cultivar (19.8 % of the state acreage).
In 2000, one new wheat cultivar was recommended for release. Wahoo is a HRWW cultivar developed cooperatively by the Nebraska Agricultural Experiment Station and the USDA-ARS and most likely will be jointly released in 2001 by the developing institutions and Wyoming Agricultural Experiment Station. Wahoo was selected from the cross 'Arapahoe/Abilene//Arapahoe'. Wahoo was released primarily for its superior adaptation to rainfed wheat production systems in eastern Nebraska and broad adaptation to rainfed wheat production systems in Wyoming and Nebraska.
Wahoo is an awned, white-glumed cultivar with a field appearance is most similar to that of Arapahoe. After heading, the canopy is moderately open and upright. The flag leaf is erect and twisted at the boot stage. The foliage is green with a waxy bloom at anthesis. The leaves are pubescent. The spike is tapering in shape, mid-long, and middense. The glume is midlong and narrow, and the glume shoulder is narrow and square. The beak is medium to long in length with an acuminate tip. The spike is usually nodding at maturity. Kernels are red-colored, hard-textured, midlong, and elliptical in shape. The kernel has no collar, a large brush of medium length, rounded cheeks, midsize germ, and a midwide and shallow crease.
Wahoo was performance tested as NE94654 in Nebraska yield nurseries starting in 1995 and in the Northern Regional Performance Nursery in 1998 and 1999 and in Nebraska cultivar performance trials in 1999 and 2000. In two years of testing in Nebraska cultivar performance trials, it has performed extremely well throughout most of Nebraska, but it is best adapted to eastern Nebraska. It also preformed well in Wyoming. The average Nebraska rainfed yield of Wahoo (27 environments) was 3,620 kg/ha (53.8 bu/acre) that compares favorably to those of Alliance (3,550 kg/ha, 52.7 bu/acre), Culver (3,510 kg/ha, 52.2 bu/acre), and Millennium (3,580 kg/ha, 53.3 bu/acre). In Wyoming (nine environments), it averaged 2,590 kg/ha (38.6 bu/acre), which was superior to Buckskin (2,390 kg/ha, 35.6 bu/acre) and Pronghorn (2,380 kg/ha, 35.4 bu/acre). Wahoo has not performed well under irrigation and is not recommended for use in irrigated productions systems. Wahoo was tested in the Northern Regional Performance Nursery in 1998 and 1999. It ranked 16th of 28 entries in 1998 (17 environments) and 6th of 29 entries in 1999 (18 environments) and averaged 225 kg/ha (3 bu/acre) higher yielding than Abilene. The main advantages Wahoo has, when compared to most other available wheat cultivars within its area of adaptation, is its high grain yield and broad adaptation in rainfed production systems.
Other measurements of performance from comparison trials show that Wahoo is medium in maturity, about 0.5 days earlier flowering than Arapahoe and similar but slightly later than Wesley. However, Wahoo tends to be more variable in its flowering date than either Arapahoe or Wesley. Wahoo has a longer coleoptile length (53 mm) for a semidwarf wheat, longer than those of Arapahoe (50 mm) and Millennium (43 mm); but shorter than that of Cougar (76 mm), a semidwarf line with a different semidwarfing gene that does not affect coleoptile length. The mature plant height of Wahoo (36 in, 92 cm) is 2 in (5 cm) shorter than Arapahoe and 2 in (5 cm) taller than Wesley. Wahoo has moderate straw strength, similar to that of Arapahoe, but lower than that of Wesley, Alliance, and Millennium. The winter hardiness of Wahoo is good to very good, similar to that of Abilene and comparable to other winter wheat cultivars adapted and commonly grown in Nebraska.
Wahoo is moderately resistant to stem rust (most likely containing
Sr6 and Sr24), leaf rust (most likely contains Lr16,
Lr24, and possibly other leaf rust resistance genes), and
Hessian fly (similar to Arapahoe and most likely contains the
Marquillo-Kawvale genes for resistance), and susceptible to WSBMV,
WSMV, and BYDV. Wahoo is a genetically lower in grain volume
weight ( 57.2 lbs/bu, 73.8 kg/hl) similar to those of Arapahoe
and Wesley, but lower than those of Culver, Millennium, Alliance,
and Pronghorn. The milling and baking properties of Wahoo were
determined for 6 years by the Nebraska Wheat Quality Laboratory.
In these tests, Arapahoe and Scout 66 were used as check cultivars.
The average wheat protein content of Wahoo was similar to that
of Scout 66 and lower than that of Arapahoe. The average
flour extraction on the Buhler Laboratory Mill for the Wahoo was
similar to that of Scout 66 and higher than that of Arapahoe.
The flour ash content was higher than both check varieties. The
average flour protein content was less than both check varieties.
Dough mixing properties of Wahoo were similar to those of Arapahoe
and stronger than those of Scout 66. Average baking absorption
was slightly less than the check varieties. The average
loaf volume of Wahoo was similar to that of Scout 66 and less
than that of Arapahoe. Scores for the internal crumb grain
and texture were good, which was similar to Arapahoe but less
than Scout 66. The overall end-use quality characteristics
for Wahoo should be acceptable to the milling and baking industries.
In preliminary noodle quality tests, noodles made from Wahoo
discolor less over time than noodles made from flour from most
other hard red winter wheat varieties. Noodle discoloration is
an undesirable trait in the marketplace.
In positioning Wahoo, based on performance data to date, it should
be well adapted to most rainfed wheat production systems, with
average or above average yield potential in most of Nebraska.
Wahoo has performed exceptionally well in eastern Nebraska and
should be grown there as a medium maturity wheat variety. The
cultivar should perform well in similar growing areas in adjacent
states. Where it is adapted, Wahoo should be a good replacement
for Arapahoe as it has a higher yield potential, similar straw
strength, and similar disease and insect resistances. Wahoo is
genetically complementary to 2137, Alliance, Jagger, Pronghorn,
and Windstar but noncomplementary to Arapahoe (one of its parents),
Culver, Millennium, Niobrara, and Vista. Wahoo has been uniform
and stable since 1999. Less than 0.5 % of the plants were rogued
from the Breeder's seed increase in 1999. The rogued variant
plants were taller in height (10-15 cm), or were awnless with
red chaff. Up to 1 % (10:1000) variant plants may be encountered
in subsequent generations. The Nebraska Crop Improvement Association
provided technical assistance in describing the cultivar characteristics
and accomplishing technology transfer. The Nebraska Foundation
Seed Division, Department of Agronomy, University of Nebraska-Lincoln,
Lincoln, NE 68583, had foundation seed available to qualified
certified seed enterprises in 1999. The U.S. Department of Agriculture
will not have seed for distribution. The seed classes will be
Breeder, Foundation, Registered, and Certified. The Registered
seed class will be a nonsalable seed class. Wahoo will be submitted
for registration and plant variety protection under P.L. 10577
with the certification option.
A new forage triticale (X Triticosecale rimpaui Wittm.) cultivar also has been recommended for release under the name T422. T422 was developed cooperatively by the Nebraska Agricultural Experiment Station and the USDA-ARS. T422 was selected from the cross 'Trical/UB-UW26' where Trical is most likely Trical 100 (a forage triticale developed by Resource Seed Inc., a subsidiary of Goldsmith Seed Company, Gilroy, CA) and UB-UW26 is an unknown winter triticale germ plasm line given to the breeding program in the 1980s. T422 is an F3-derived F4 line that was released primarily for its superior forage production in rainfed winter cereal production systems in Nebraska.
T422 is an awned, white-glumed cultivar whose primary use will be as an annual forage crop with a field appearance is most similar to that of Trical 100. Kernels are red-colored, elliptical, large, and slightly wrinkled (as is common with triticale). Based on plump kernels, the kernel has no collar, a large brush of long length, rounded cheeks, large germ, and a narrow and deep crease.
T422 was performance tested as NE96T422 in Nebraska grain yield nurseries starting in 1997 and in forage yield trials in 1997 and 1998. In 2 years of forage testing in Nebraska cultivar performance trials, T422 has performed extremely well throughout most of Nebraska in rainfed production systems. The average Nebraska rainfed forage yield cut at the R2 (fully headed but the peduncle not fully emerged) to R4 (anthesis, Nebraska scale) of T422 (six environments) was 9,070 kg/ha dry matter, with an average in vitro dry matter digestability of 63.9 % and an average protein content of 9.0 %. These data compare favorably with Newcale (a grain triticale: 8,730 kg/ha, 67.9 %, and 8.5 %) and Trical 100 (8,530 kg/ha; 63.5 %, and 9.0 %). For further comparison, the forage yields of T422 were higher than two commonly grown wheat cultivars Arapahoe (7,200 kg/ha, 67.7 %, 8.5 %) and Pronghorn (7,930 kg/ah, 67.0 %, 8.6 %). The wheat cultivars are earlier than T422 and were cut at the R4 to S0 (caryopsis visible, Nebraska scale). T422 has a good grain yield (10 environments; 2,790 kg/ha) for a forage triticale. The grain yield was higher than that of Trical 100 (2,040 kg/ha), but lower than that of grain triticale cultivars (Presto, 3,620 kg/ha; Newcale, 3,120 kg/ha). For comparison, the grain yield of Arapahoe was 3,050 kg/ha, which is lower than the grain triticale yields and might be explained by triticale yield nurseries generally be planted near, but earlier than the wheat yield trials. The main advantages of T422 when compared to most other forage triticale cultivars, within its area of adaptation, is its high forage yield coupled with a good grain yield (needed for efficient seed production) and its broad adaptation in rainfed production systems.
Other measurements of performance from comparison trials show that T422 is late in maturity, about 7 days later than Newcale, 6 days later than Presto, 5 days later than Arapahoe, and 1 day earlier than Trical 100. The mature plant height of T422, a tall triticale (58 in; 148 cm) is 3 in (7.5 cm) taller than Trical 100, 12 in (31 cm) taller than Presto and Newcale, and 19 in (49 cm) taller than Arapahoe. T422 has moderate straw strength for a tall, forage triticale. T422 is slightly better than Trical 100 lodging, but worse than Presto, Newcale, and Arapahoe. The winter hardiness of T422 would be consider as good, similar to that of Trical 100, which is one of the most winter hardy triticale cultivars currently available to grower, and comparable to an average winter wheat for this trait. T422 has an average grain volume weight for triticale.
Based on field observations, T422 is moderately resistant to the currently prevalent races of stem (most likely containing Sr31) and leaf rust. Like most ryes and triticales, T422 is moderately resistant to WSMV. Ergot has not been found in the cultivar when the disease was present in the other triticales under similar growing conditions.
A. Mitra, T. Clemente, S. Sato, S. Baenziger, M. Dickman, and
J. Watkins.
Wheat transformation continues to be a key strategic effort in
the wheat improvement overall effort. In our current research,
we are emphasizing trying to develop wheat lines with improved
FHB resistance as part of the U.S. Wheat and Barely Scab Initiative.
This is a collaborative effort between Dr. T. Clemente and Ms.
S. Sato of the Transformation Core facility (wheat transformation),
Dr. J. Watkins and Ms. J. Schimelfenig of the Department of Plant
Pathology (screens conventionally bred and transgenic wheat lines
with FHB), and Drs. A. Mitra and M. Dickman, also of the Department
of Plant Pathology, who are studying new concepts in disease resistance.
Ms. S. Mitra has been very helpful in maintaining the plants
and doing much of the transgene analysis. An Agrobacterium tumefaciens-based
transformation system is now routinely used for transformation.
So far, we have concentrated on transforming the following genes:
a) inhibitors of apoptosis (programmed cell death), ced9, IAP,
and BCL X(L); b) lactoferrin and a related derived protein, lactoferricin;
and c) oxalyl-CoA-decarboxylase. With the exception of BCL X(L)
where the work is in progress, we have created over 10 events
for the other genes. In many cases, the T1 plants have been screened
for FHB tolerance and T2 seed has been harvested. Seed from plants
in the T1 and T2 generations which appear to have useful levels
of FHB tolerance are being planted in the greenhouse for crossing
to known FHB-susceptible and resistant lines. Those crosses will
be made this year on our most advanced material. The cross to
the FHB-susceptible line will help understand the inheritance
of the putative FHB tolerance and the cross to the FHB-resistant
lines will indicate if the transgenic line can increase the level
of FHB resistance above what is currently the best level of FHB
tolerance in conventionally bred lines. One of the difficulties
with working with FHB and transgenic lines is that FHB is a notoriously
difficulty disease to work with and requires many plants and multiple
heads per plant to be screened. Hence, working with early generation
transgenic material is very difficult.
K.S. Gill, S. Baenziger, M. Shah, H. Budak, T. Campbell, and
M. Erayman.
This research was undertaken with the expectation that as we learned
more about the wheat genome, we would be able to develop better
breeding strategies. The work is done in collaboration with Drs.
Kent Eskridge, Kulvinder Gill, and Dan Nettleton. Dr. Mohammed
Maroof Shah, a former graduate student, has rejoined our project
after postdoctoral fellowships at Iowa State University and University
of Nebraska with Kulvinder Gill on another project. Mr. Mustafa
Erayman, Todd Campbell, and Hikmet Budak are graduate students
who actively working various aspects of this project. Mustafa
is 'binning' the known probes for chromosome 3A using deletion
stocks developed at Kansas State University. His research is
helping us understand the recombinational map and the physical
map for chromosome 3A. This effort is needed to fill in the
gaps in our map and to determine the physical size of the critical
chromosome regions. Todd is evaluating 98 RICLs for Cheyenne
(CNN)Wichita (WI) chromosome 3A lines (e.g., CNN(RICLs3A))
in the field and increasing the number of markers on our map for
chromosome 3A. Todd has more replications in each testing location
than we have had in the past, so he should be able to more tightly
link markers to traits of interest and to thoroughly study 'genotype
x environmental' interactions. Hikmet is increasing the seed
of WI(RICLs3A), the mirror image set of lines to Todd's CNN(RICLs3A)
to determine if the genes/QTLs in WI(CNN3A) that reduce the yield
of WI(CNN3A) compared to WI are at the same location as the genes/QTLs
in CNN(WI3A) that increase the yield of CNN(WI3A) compared to
CNN. Hikmet also will be involved with adding markers to chromosome
3A.
D. Baltensperger and S. Baenziger.
A small spring-sown wheat breeding effort was initiated in
1997. We have been very fortunate to work closely with Dr. Jackie
Rudd of South Dakota State University graciously shared his elite
trial and 30 bulks for our evaluation. In addition, we are making
about 40 crosses each year to develop germ plasm with good adaptation
for our Nebraska environments. We have normally grown the spring
wheat trials (planted and harvested by Dr. D. Baltensperger) at
Sidney, but are considering having additional trials at Alliance,
where the cool nights might provide better growing conditions
for spring wheat. We have some Clearfield® resistant spring
wheats from our crosses to adapted types. They have been sprayed
in the greenhouse and were segregating, but there are several
resistant plants from each of a half dozen crosses to adapted
types. All the checks died. We hope to get them to the field
again this spring for increase and testing (the amount of testing
will be seed dependent but should be enough for at least 3 locations
of 3 reps). With the addition of the white wheat breeding efforts
to the state-breeding program, a decision was made to transfer
the leadership of the spring wheat efforts to Dr. D. Baltensperger
as he is the one closest to the needs of the program. Crosses
will continue to be made at Lincoln.
R. Graybosch, S. Baenziger, D. Baltensperger, and M. Shipman.
More than 100 hard winter wheats derived from the Kansas cultivar Ike were used in a coöperative project (with Steve Delwiche, USDAARS, Beltsville) to develop NIR calibrations to predict wheat starch amylose content. Waxy wheats can be readily segregated from wild-type and partial waxy by NIR models. Partial waxy (reduced amylose wheats) and wild-type hard winter wheats were grown in a 'G X E' trial. Samples will be used in a study to define the relative effects of G, E, and 'G X E' on noodle qualityA 'G X E' trial for spring-sown waxy wheats was grown in Arizona, North Dakota, and Idaho. Samples are being tested for the stability of waxy starch properties. Breeding trials of advanced hard white wheats were conducted. Several lines were selected for advancement to state and regional trials. NW97S278 has performed well in four independent noodle-color tests and likely will be the next HWWW cultivar released in Nebraska. Breeding efforts to develop adapted winter waxy wheats were conducted. In 2000, numerous head row populations were seeded at Lincoln - from such populations we hope to derive the first winter-hardy waxy wheats.
Devinder Sandhu, Svetlana Bondareva, Julie Champoux, and Kulvinder S. Gill.
Wheat belongs to tribe Triticeae of family Poaceae. Gene synteny is highly conserved among species of Triticeae and moderately among the Poaceae. The short arm of the Triticeae homoeologous group-1 chromosomes is known to contain many agronomically important genes. Most of these useful genes are present in a major gene cluster, which in chromosome 1BS is present in the middle satellite part and will be referred to as the FL0.85 gene cluster. The region spans about 6 % of the satellite region and is flanked by the breakpoints of deletions 1BS-4 and 1BS-19. The objectives of this study were to construct a fine physical map of homoeologous group-1 chromosomes in wheat, identify useful genes present in FL0.85 gene cluster, enrich this region with markers using RNAF/DD and comparative mapping, and study the distribution of genes and its relationship with that of recombination. A high-density, fine physical map was generated using 121 RFLP markers on 51 single-break deletion lines and compared with consensus genetic map of Triticeae and genetic linkage map of Ae. tauschii. More than 90 % of the group-1 markers were present in eight gene clusters. Recombination rates in distal regions of chromosomes were more than 20 times higher as compared to proximal regions. Recombination was confined to gene clusters. Recombination occurs preferably in gene-rich regions and also is a function of distance from the centromere. For RNAF/DD, mRNA of the two deletion lines (1BS-4 and 1BS-19) flanking FL0.85 gene cluster were amplified and size separated on a denaturing polyacrylamide-urea gel. Sixty-five fragment bands, which were present in 1BS-4 but missing in 1BS-19, were tested in a gel-blot analysis of group-1 nullisomic-tetrasomic lines and the two deletion lines. Of these, 46 were maped and the remaining 19 detected smear patterns. Twenty-two of the 46 probes, mapped to group 1 and seven mapped to the FL0.85 gene cluster. For comparative mapping, 35 different maps from Poaceae were compared with the existing wheat physical maps and 75 agronomically important genes along with 93 potential DNA markers were identified for FL0.85 gene cluster. Seventy-three of the 93 probes mapped to group 1 and detected 91 loci. Fifty-two marker loci mapped in FL0.85 gene cluster and thirteen to a second gene cluster at FL0.55 of the short arm. Part of the FL0.85 gene cluster region marked by 14 probes is duplicated on group 1 long arm.
Dr. Galal El-Sherbeny, from Egypt, joined the project for six months as a visiting scientist. Ms. Chatuporn Kuleung, from Thailand, and Mr. Fufa Hundera Birru, from Ethiopia, joined the project as graduate students.