GrainGenes

Environmental effects on plant height.

N. Budak, B. Moreno-Sevilla, D. Baltensperger, K. Eskridge, A. Weiss, and P. S. Baenziger.

With the continued interest in taller wheats for western Nebraska, Dr. Necdet Budak completed his research on how to better understand factors determining plant height. He tried to find lines that are not too tall in eastern Nebraska, but are tall in western Nebraska. He has determined that tall wheats tend to be tall in all locations or to be tall in eastern Nebraska (where they are generally too tall) and rapidly become shorter in western Nebraska (where the tall wheats are needed). Semidwarf wheats can be short in every environment or moderately tall in eastern Nebraska and retain their height in western Nebraska. Hence, it may be possible to select for tall semidwarfs that retain their height under stress conditions. NE90625, an advanced experimental line, has this attribute in addition to being very wind (blowout) resistant. Research with Dr. Al Weiss determined relatively crude climatic measurements and plant heights under optimal conditions, and preexisting wheat growth models can be used effectively to model wheat plant height in Nebraska.

Effect of 1B/1R and 1B lines in Rawhide.

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

With the well documented beneficial effects of 1B/1R on agronomic performance and deleterious effects of 1B/1R on end-use quality in bread wheats, a number of inquiries have been received as to how it was possible to release Rawhide, a cultivar that is heterogeneous for 1B and 1B/1R. Rawhide was advanced in the breeding program on the basis of its good agronomic performance (particularly in stressed environments, hence its name) and acceptable end-use quality. Only during the final stages of testing and seed increase did we discover that it was heterogeneous. This led us to wonder if the 1B/1R genotypes were agronomically superior to the 1B genotypes, and if the 1B genotypes were superior for end-use quality to the 1B/1R genotypes. The overall effect would be that the 1B/1R genotypes compensated agronomically for the 1B genotypes, whereas the 1B genotypes compensated for the end-use quality of the 1B/1R genotypes. The alternative hypothesis was that Rawhide may be a genetic background in which 1B/1R is not beneficial agronomically or deleterious for end-use quality. Nineteen 1B lines derived from Rawhide, 18 1B/1R lines derived from Rawhide, a composite of 1B lines, a composite of 1B/1R lines, a composite of all lines, and Rawhide were grown in replicated trials in four environments in Nebraska. For grain yield, the average of the 1B lines, the average of the 1B/1R lines, the composites, and Rawhide were not significantly different. Hence in these environments (generally more favorable than normal) and in this genetic background, 1B/1R was not beneficial agronomically. Because these environments had less stress than normal, the agronomic benefits of 1B/1R may not have been expressed. It should be noted that in the initial identification of 1B and 1B/1R genotypes in Rawhide, the frequency of the two classes did not differ from 1:1 as would be expected for a neutral trait. For end-use quality as determined by flour protein and the mixograph, the 1B/1R lines averaged higher flour protein content, similar mixing times, and lower mixing tolerances than the 1B lines. The surprise was that the average mixing tolerance of the Rawhide 1B/1R lines was similar to that of Ram (a 1B cultivar) and higher than that of Arapahoe (also a 1B cultivar, with an good reputation for end-use quality). The 1B composite also was not better for end-use quality than Rawhide. Hence, although 1B/1R reduces mixing tolerance, it apparently was still acceptable in this genetic background. Similarly, no advantage or disadvantage would be achieved agronomically or for end-use quality by releasing a 1B composite derived from Rawhide.

A similar project to understand the heterogeneity (1A and 1A/1R) in Nekota and Niobrara has been initiated by Mr. Eduardo Espitia-Rangel.

Molecular genetic analysis of rye chromosome 1R transferred to wheat.

Jai-Heon Lee, R.A. Graybosch, C. J. Peterson, and David Porter (USDA-ARS, Stillwater, Oklahoma).

The 1AL-1RS translocation found in 'Amigo' wheat possesses genes for stem rust, powdery mildew, and greenbug resistance. Recently, new germplasm lines GRS 1201 and GRS 1205, with resistance to greenbug biotypes B, C, E, G, and I, were identified. 1RS of the GRS lines was differentiated from 1RS derived from Amigo using protein gel electrophoresis, immunochemical methods, and the polymerase chain reaction. GRS 1201 carries a 1AL-1RS wheat-rye chromosomal translocation, whereas GRS 1205 was found to possess an entire rye chromosome (1RL-1RS) substituted for wheat chromosome 1A. Among 1RS sources, polymorphic banding patterns specific to each line were observed. Protein (secalin and 1A HMW glutenin) and PCR markers also were used to determine whether recombination occurs between rye chromosomes and wheat homoeologous chromosomes and 1RS chromosome arms in wheat genetic backgrounds. Recombination between homoeologous chromosomes was not observed in two populations derived from crosses between nontranslocation and 1AL-1RS translocations. The Amigo and GRS sources of 1RS carry different alleles at the Sec-1 locus. Two putative recombinants from a cross of a nontranslocation stock and the 1R(1A) substitution were found. The PCR markers were located about 13.94 cM from the secalin protein markers. A map distance of 37.90 cM was estimated between the secalin markers and the centromere. The map distance between the greenbug resistance locus and the secalin locus was 6.22 cM.

Molecular markers for a 2BS-2RL wheat-rye chromosomal translocation.

J-H. Lee, R.A. Graybosch, S. Kaeppler (University of Nebraska), and R.G. Sears (Kansas State University).

A 2BS-2RL wheat-rye translocation, 'Hamlet', derived from crosses between 'Chaupon' rye and hexaploid wheat, has a resistance gene to Hessian fly biotype L. Biotype L is the most virulent biotype presently found in the field. However, 2RL does not have any storage protein or other easily scored markers. This can be a significant problem for plant breeders in identifying resistant lines, because screening for insect resistance can be difficult. In this research, we identified PCR markers specific to rye chromosome 2RL and verified 2RL rye chromosomal segments by genomic in situ hybridization.

Genotypic and environmental modification of wheat flour protein composition in relation to end-use quality.

R.A. Graybosch, C.J. Peterson, D.R. Shelton, and P.S. Baenziger.

Identification of the biochemical factors responsible for end-use quality variation of wheat (Triticum aestivum L.) would have important consequences for breeders, producers, grain handlers, millers, and bakers. Flour protein composition, or the distribution of flour protein in classes based on molecular size and solubility, has been reported to be a major variable influencing wheat processing quality. The proportion of five major protein fractions in flour samples of 30 wheat genotypes, obtained from 17 Nebraska locations, were measured using SE-HPLC. Total flour protein content and SDS sedimentation volume, the latter a measure of flour protein aggregative ability, also were measured. The extent to which each character was modified by genotypic, environmental, and GXE sources of variation was determined. Both phenotypic and genotypic correlations were used to relate biochemical variation to wheat end-use quality characteristics. Genotypic differences in loaf grain and loaf texture, two variables of critical importance to the baking industry, were

correlated most highly with the proportions of glutenin and saline-extractable protein (SEP) of Mr 25K-100K. SDS sedimentation volume was the one trait most consistently correlated with quality variables and the only trait for which GXE variance exceeded the genotypic variance. Use of the relatively simple SDS sedimentation test as a means of identifying genotypes with stable responses across environments could be of service to breeders as a substitute for more expensive and laborious baking and dough testing.

Personnel.

Dr. Necdet Budak completed his Ph.D. degree and returned to Ege University in Turkey. Dr. Vicki Gustafson completed her Ph.D. degree and is now at the University of Minnesota. Dr. Benjamin Moreno-Sevilla completed his Ph.D. degree and continues to be the project leader while P.S. Baenziger is interim department head. P.S. Baenziger will resume his efforts as project leader on July 1, 1995. Ms. Carla Wildhagan-Kimball completed her M.S. degree and has joined her spouse on a ranch/farm in central Nebraska. Mr. Eduardo Espitia-Rangel, Mr. Mohammed Maroof Shah, and Mr. Kyung-Moon Kim have joined the project as Ph.D. students.

Publications.

Baenziger PS and Mitra A. 1994. Augmenting our current efforts to increase crop yield. In: Breaking the Yield Barrier (Cassman KG ed). November 29-December 4, 1993, International Rice Research Institute, Los Banos, Philippines. Pp. 121-126.

Baenziger PS, Moreno-Sevilla B, Yen Y, Oberthur L, and Gustafson V. 1994. Wheat breeding and genetics. In: Encyclopedia of Agricultural Science Vol. 4 (Arntzen C ed). Academic Press. pp. 515-523.

Graybosch RA, Peterson CJ, Baenziger PS, and Shelton DR. 1995. Environmental modification of hard red winter wheat flour protein composition. J Cereal Sci (In Press).

Graybosch RA, Peterson CJ, and Shelton DR. 1994. Environmental modification of wheat flour quality and protein composition in the northern Great Plains of North America. Proc 44th Australian Cereal Chemistry Conference, Sept. 12-15, Ballarat, Australia.

Lee JH, Graybosch RA, and Peterson CJ. 1994. Quality and biochemical effects of a 1BL/1RS wheat-rye translocation in wheat. Theor Appl Genet (In Press).

Navarro-Alvarez W, Baenziger PS, Eskridge KM, Shelton DR, Gustafson VD, and Hugo M. 1994. Effect of sugars on wheat anther culture media. Plant Breed 112:53-62.

Navarro-Alvarez W, Baenziger PS, Eskridge KM, Hugo M, and Gustafson VD. 1994. Addition of colchicine to wheat anther culture media to increase doubled haploid plant production. Plant Breed 112:192-198.

Peterson CJ, Graybosch RA, Eskridge KM, and Shelton DR. 1994. Effects of genotype, environment, and GxE interactions on the end-use quality of hard red winter wheat. Proc 44th Australian Cereal Chemistry Conference, Sept. 12-15, Ballarat, Australia.

Stroup WW, Baenziger PS, and Mulitze DK. 1994. A comparison of methods for removing spatial variation from wheat yield trials. Crop Sci 34:62-66.

Yen Y and Baenziger PS. 1994. Wheat chromosome 2D carries genes controlling the activity of two DNA-degrading enzymes. Theor Appl Genet 88:30-32.

M.E. Sorrells.