Genetic and Molecular Characterization of Vernalization Genes Vrn-A1, Vrn-B1, and Vrn-D1 in Spring Wheat Germplasm from the Pacific Northwest Region of the USA.

Authors: SANTRA, D - WA STATE UNIV; SANTRA, M - WA STATE UNIV; ALLAN, R - USDA-ARS RETIRED; Garland-Campbell, Kimberly; KIDWELL, K - WA STATE UNIV

Submitted to: Journal of Theoretical and Applied Genetics
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/5/2009
Publication Date: 8/31/2009
Citation: Santra, D., Santra, M., Allan, R.E., Garland Campbell, K.A., Kidwell, K. 2009. Genetic and Molecular Characterization of Vernalization Genes Vrn-A1, Vrn-B1, and Vrn-D1 in Spring Wheat Germplasm from the Pacific Northwest Region of the USA. Journal of Theoretical and Applied Genetics. Vol 128: 576-584.

Interpretive Summary: Spring wheat possesses one of three dominant alleles at the Vrn-1 loci that cause it to be insensitive to vernalization. The alleles at the Vrn-A1 locus result in complete insensitivity to vernalization while alleles on the B and D genomes retain some sensitivity. These differences affect growth of the wheat plants throughout the short spring wheat growing season. The objective of this research was to discern proportion of the various dominant spring wheat alleles in a collection of genotypes and breeding lines from the Pacific Northwest. Most of the germplasm carried the dominant Vrn-A1a allele but a unique allele was discovered in the drought tolerant spring wheat cultivar, Alpowa. This results of this research indicate that, although the dominant allele on the A genome for insensitivity to vernalization seems to be favored in the PNW, alternate alleles can be useful.

Technical Abstract: Spring wheat genotypes carrying specific combinations of dominant Vrn-1 alleles were reported to have higher grain yield potential than other lines; therefore, it may be possible to improve spring wheat yields by manipulating these alleles. The objective of this study was to determine the Vrn-1 allele composition of spring wheat germplasm from the Pacific Northwest region of the U.S. Individual plants from 56 spring wheat lines were cross-hybridized to near-isogenic testers carrying the dominant allele Vrn-A1, Vrn-B1 or Vrn-D1. Progenies from 1 to 4 F2 families per line by tester combination were evaluated for growth habit type in the field and Vrn-1 allele composition was determined through chi-square analysis. Lines also were analyzed with Vrn-1 allele specific DNA markers, which were developed using DNA sequence information for each allele. Vrn-1 allele compositions of 35 lines were determined based on genetic segregation and DNA marker analyses. Due to weather related misfortune in the field, only DNA marker analysis was used to determine Vrn-1 allele composition of the remaining 21 lines. A majority of the germplasm carried the dominant allele Vrn-A1a alone or in combination with other dominant Vrn-1 allele (s). Vrn-B1 and Vrn-D1 were almost always associated with other dominant Vrn-1 allele(s). A novel Vrn-B1 allele was identified in the cultivar Alpowa, in which the Vrn-B1 allele specific marker amplified a 673 bp instead of a 709 bp fragment, as was expected. A SNP and a 36 bp deletion were identified in the novel allele based on DNA sequence analysis. These results will be useful to wheat breeders for identifying parents with different Vrn-1 alleles for cross-hybridization to maximize diversity at Vrn-1 loci with an expectation of identifying superior Vrn-1 allele combinations for cultivar enhancement.