GrainGenes

NEBRASKA

UNIVERSITY OF NEBRASKA AND THE USDA-ARS

Department of Agronomy, Lincoln, NE 68583, USA.

Growing conditions and production.

P.S. Baenziger, C.J. Peterson (USDA-ARS), R.A. Graybosch (USDA-ARS), D.R. Shelton, L.A.Nelson, D.D. Baltensperger, D.J. Lyons, G.L. Hein, and J.E. Watkins.

The 1994-95 growing season can be described as being the best of times and the worst of times, depending where the wheat was produced in Nebraska. The best crop was produced in western Nebraska, where above-average spring rainfall greatly enhanced yields. Western Nebraska had very little fall moisture, and semidwarf, short-coleoptile wheats had difficulty emerging in some fields. The worst crop was in southeastern Nebraska where excessive rainfall during grain filling virtually destroyed the crop because of diseases. The estimated production was 2,350,000 metric tons (86.1 million bushels) from 850,000 ha (2.1 million harvested acres) with a state average yield of 2,750 kg/ha (41 bu/acre). This is a 475 kg/ha higher yield than last year and would be considered a good production year. `Arapahoe' continued to be the most popular wheat (grown on more than 30 % of the wheat hectarage). Winterkill was minimal throughout the state. In 1995, the main diseases were scab, head blight (Septoria spp.), and root rots (excessive moisture prevented a good root system from being developed, which also provided insufficient rooting when the heat came). In general, most insects pests were at low levels on wheat in 1995.

New Cultivars. `Pronghorn' (formerly NE88584) was released by the Nebraska Agricultural Experiment Station in cooperation with the Wyoming Agricultural Experiment Station; the South Dakota Agricultural Experiment Station; and the Northern Plains Area, Agricultural Research Service, U. S. Department of Agriculture. The name was chosen to represent the region to which the namesake and the cultivar are adapted.

Pronghorn is an increase of a hard red winter wheat F3-derived line from the cross `Centura/Dawn//Colt sib', which was made in 1982 by Dr. J.W. Schmidt. Pronghorn was identified as a line in 1988 and tested as NE88584 in Nebraska yield nurseries starting in 1989 and in the Southern Regional Performance Nursery starting in 1991 and the Western Regional Performance Nursery in 1993. The current breeder seed originated from a purification program in 1991-92 and 1992-93 designed to remove off-types by roguing.

Pronghorn is a white-chaffed, awned, tall wheat with medium maturity, and is 1.5 days earlier than Arapahoe and Lamar and 1 day earlier than Buckskin. Pronghorn is 2.5 cm shorter than Buckskin, 2.5 cm taller than Lamar, and 5 cm inches taller than Arapahoe. Pronghorn has moderate straw strength, greater than Scout 66, but less than Buckskin, Centura, Siouxland, and Thunderbird. Pronghorn has exhibited moderate resistance to stem rust (contains Sr6 and Sr17) and is moderately susceptible to leaf rust. Pronghorn is susceptible to the Great Plains biotype of Hessian fly, soilborne mosaic virus, and wheat streak mosaic virus. The winterhardiness of Pronghorn is comparable to with other winter wheat cultivars adapted and commonly grown in Nebraska and South Dakota. Its winterhardiness is similar to that of Arapahoe and Buckskin and superior to that of Vona, TAM 200, and Rawhide. Pronghorn is a genetically high test weight wheat, similar to Buckskin, Siouxland, and Scout 66 and superior to Arapahoe.

The recommended growing area for Pronghorn, based on current information, is the dryland wheat production areas of the panhandle of Nebraska, eastern Wyoming, and western South Dakota. Using western Nebraska data from the Nebraska Fall Sown Cereal Variety Trials from 1993, 1994, and 1995 (16 environments); data from the Western Regional Performance Nursery in 1993 and 1994 (17 environments); and data from Wyoming in 1994 and 1995 (11 environments), Pronghorn (2,940 kg/ha) was 70 kg/ha higher yielding than Lamar and 130 kg/ha higher yielding than Arapahoe. Using data from only western Nebraska and from Wyoming (27 environments), the yields of Pronghorn, Buckskin, Lamar, and Arapahoe were similar. In 5 years of testing in the advanced trials in Nebraska (24 environments), Pronghorn (3,100 kg/ha) was 130 kg/ha lower yielding than `Alliance'; 70 kg/ha lower yielding than Redland, Vista, and Niobrara; similar to Rawhide and Siouxland; 130 kg/ha higher yielding than Arapahoe; 200 kg/ha higher yielding than TAM107; and 200 kg/ha higher yielding than Buckskin.

Pronghorn has a long coleoptile similar to that of Scout 66 and can be planted deep in dry seedbeds. Pronghorn is tolerant to aluminum- toxic soils. For dryland wheat production, Pronghorn is complementary to Buckskin, which also is tall and has a long coleoptile. The main advantage that Pronghorn has when compared to Buckskin is its superior stem rust resistance, which is conparable to that of Lamar. Buckskin is susceptible to the current field races of stem rust.

The milling and baking properties of Pronghorn were determined using 7 years of testing by the Nebraska Wheat Quality Laboratory with Arapahoe and Scout 66 as check cultivars. Four years of comparisons are available between Pronghorn and Buckskin. The average wheat and flour protein contents of Pronghorn are higher than those of Arapahoe, Scout 66, and Buckskin. The dough-mixing properties were stronger than those of Arapahoe and Scout 66, but similar to those of Buckskin, though Pronghorn has the best mixing tolerance. Although the baking absorption of Pronghorn was less than those of Arapahoe, Scout 66, and Buckskin, average loaf volumes were greater than those of Arapahoe, Scout 66, and Buckskin. The external appearance and internal attributes of the baked bread loaf indicated generally acceptable quality characteristics.

Increase of New Experimental Lines. Three experimental wheats are in large-scale increase for possible release in 1996. In addition, the decision on the release of one line that was under possible increase for 1995 has been deferred until 1996. The three lines currently under large-scale increase are NE90625 (TX79A2729//Caldwell/Brule field sel #6/3/Siouxland), NE91631 (NE82761 (= CO725082 2*/RRI)/Brule 84 sel.), and NE91648 (NE82671 (= CO725082 2*/RRI)/2/Ctk78*2/Lov 13). The line for which a decision was deferred is NE90479 (KS83H2510 (H11)/Brule 83 composite).

NE90479 is a moderately tall, intermediate coleoptile length wheat (similar to TAM 107) with average straw strength, large kernels, and very good test weight characteristics. NE90479 would be considered a medium-maturity wheat. The line is moderately resistant to stem rust and wheat soilborne mosaic virus; and moderately susceptible to leaf rust, Hessian fly, and wheat streak mosaic virus; and susceptible to Russian wheat aphid. In its first year of testing in the state variety trial, it seemed to do particularly well in eastern and southeastern Nebraska. This is the first Nebraska wheat in many years with good resistance to wheat soilborne mosaic virus, helping its adaptation in southeastern and south central Nebraska, which would be its targeted area. However, in its second year of testing, it performed below average in Nebraska. The overall milling and baking quality would be considered well above average. This is a good quality wheat with a high test weight and superior protein content. However, NE90479 probably has a low likelihood of release in 1996, based on its previous erratic performance.

NE90625 is a taller semidwarf wheat that retains its height in shorter-height environments and has a shorter coleoptile (similar to Redland) and above average straw strength. The line has intermediate-sized kernels and appears to be genetically lower in protein and test weight. NE90625 would be considered a late-maturity wheat. NE90625 is moderately resistant to stem rust (contains Sr6 and Sr24) and to leaf rust, moderately susceptible to wheat streak mosaic virus, and susceptible to Hessian fly and the Russian wheat aphid. In its second year of testing in the state variety trial, it seemed to do particularly well in western Nebraska, where its lateness is not detrimental. Anecdotal observations indicate that this wheat may be resistant to wind erosion. The overall milling and baking quality would be considered acceptable.

NE91631 is a tall wheat that may lose some of its height potential in shorter-height environments and has a short coleoptile (similar to Vona) and above average straw strength. The line has small-sized kernels and appears to be genetically lower in protein and test weight. NE91631 would be considered a late-maturity wheat. NE91631 is moderately resistant to stem rust (contains Sr6, Sr16, and Sr24), to leaf rust, and to Hessian fly and is susceptible to wheat streak mosaic virus and the Russian wheat aphid. In its first year of testing in the state variety trial, it did well across the state where it appears to have coupled stress tolerance (good finish under heat) with a lateness that gave full-season growth. The overall milling and baking quality would be considered acceptable although the average wheat and flour protein contents are 2.0 % less than that of Arapahoe. NE91631 would be considered as having the best potential for release in 1996.

NE91648 is a moderately tall wheat with an intermediate length coleoptile (similar to Arapahoe) and moderate straw strength (similar to Arapahoe) and has medium-sized kernels, above-average test weight patterns, and a medium to low protein content. The line would be considered as a medium-late maturity wheat. NE91648 is moderately resistant to stem rust (contains Sr6, Sr17, and other minor genes); appears to be moderately susceptible to wheat streak mosaic viru;, and is susceptible to leaf rust, Hessian fly, and the Russian wheat aphid. NE91648 tends to be more susceptible to the leaf blight complex (Septoria spp., tan spot, etc.) than other Nebraska wheats. In its first year of testing in the state variety trial, it performed well, and its lateness avoided head blights and in dryland western Nebraska where foliar diseases were minor. The overall milling and baking quality would be considered acceptable.

Doubled haploid and wheat tissue culture studies.

K. Haliloglu, P.S. Baenziger, A. Mitra, and Y. Yen.

Improving our ability to make doubled haploids was part of the research of Mr. Kamil Haliloglu. In his research, he identified that anther-derived embryoids, which were relatively large at 4 to 8 weeks after anther cultures were initiated, regenerated better than smaller embryoids or older embryoids. He used these embryoids in electroporation experiments in cooperation with Dr. Amit Mitra. Kamil was successful in transforming one plant and will repeat these experiments.

Chromosome substitution lines.

M. Shah, Y. Yen, P.S. Baenziger, and K. Eskridge.

Previous research showed that chromosomes 3A and 6A have major effects on agronomic performance (can reduce or enhance yield by 20 %). Current efforts by Dr. Yang Yen and Mr. Maroof Shah are concentrating on developing recombinant chromosome lines, which will be used to determine how many genes on the identified chromosomes affect yield and other agronomic traits. The first replicated field experiment was harvested in 1994 and was repeated in 1995. Additional field tests are underway. So far, one major gene has been identified for maturity on chromosome 3A. The genetic nature of grain yield and other agronomic aspects remains unresolved. These experiments have shown us how difficult it is to separate relatively small yield difference (15 %) in the Great Plains.

In cooperation with Agripro Biosciences, hybrids of the chromosome substitution lines were made to identify possible chromosomal heterosis. Little or no high parent heterosis was found for agronomic traits.

Effect of 1B-1R and 1A-1R on agronomic performance and end-use quality.

B. Moreno-Sevilla, P.S. Baenziger, D. Shelton, R.A. Graybosch, C.J. Peterson, and E. Espitia-Rangel.

Previously, Dr. Benjamin Moreno-Sevilla had shown that lines containing 1B-1R from the cross `Siouxland x Ram' were 9 % higher yielding than lines with 1B or lines heterogeneous for 1B-1R. `Rawhide', a recent release, is heterogeneous for 1B and 1B-1R. The 1B-1R and 1B lines were extracted from Rawhide and grown in three environments in Nebraska in 1992 and in 1993. No difference for yield was found between the 1B and 1B-1R lines in 1992 or 1993 trials. Though the quality (determined by the mixograph) of the Rawhide 1B lines is better than that of the Rawhide 1B-1R lines, the 1B-1R lines tended to have `acceptable' quality (better than Siouxland and occasionally better than Arapahoe). The loaf volumes of the 1B-1R lines are expected to be still less than those of 1B lines.

A similar replicated study conducted by Mr. Eduardo Espitia-Rangel, in cooperation with Dr. R.A. Graybosch, using `Nekota'. In addition, a seed increase of `Niobrara' for a future replicated study was initiated. These studies will determine if 1A-1R has beneficial effects for yield or detrimental effects on quality. Both Nekota and Niobrara are released cultivars that are heterogeneous for 1A and 1A-1R. So far, 1A-1R in the Nekota background has no yield benefit.