Identification of markers linked to genes for sprouting tolerance (independent of grain color) in hard white winter wheat (HWWW)

Authors: FAKTHONGPHAN, JUTHAMAS - University Of Nebraska; Graybosch, Robert; Bai, Guihua; St Amand, Paul; BAENZIGER, STEPHEN - University Of Nebraska

Submitted to: Theoretical and Applied Genetics
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/9/2015
Publication Date: 12/22/2015
Publication URL: http://link.springer.com/article/10.1007/s00122-015-2636-4
Citation: Fakthongphan, J., Graybosch, R.A., Bai, G., St Amand, P., Baenziger, S.P. 2015. Identification of markers linked to genes for sprouting tolerance (independent of grain color) in hard white winter wheat (HWWW). Theoretical and Applied Genetics. PP 1-12.

Interpretive Summary: Interpretive Summary Excessive rainfall or high relative humidity as wheat matures can result in a condition known as “pre-harvest sprouting.” Wheat seed will commence germination while still attached to the plant. The process results in a release of starch and protein degrading enzymes. This, in turn, can damage processing quality, resulting in poor texture of bread and other defects. Hard white wheats, now preferred in both export and domestic markets, are more susceptible to pre-harvest sprouting than hard red wheats. In this study, breeding populations were developed by mating hard red to hard white wheats, and then selecting only white-seeded progeny. The progeny lines were tested for susceptibility to sprouting using samples from four Nebraska environments. The populations were also used to identify genes linked to the trait. In the three populations, marker loci with significant allelic effects were detected across the wheat genome. Chromosome 3A was the only chromosome with significant markers in all three populations. Markers were inconsistent across the three populations, and markers linked to tolerance-inducing loci were identified in both tolerant and susceptible parents. The results suggest wheat breeders can improve tolerance to pre-harvest sprouting by selection for specific genetic markers. Additional and more universal markers, however, are needed to increase the efficiency of such marker-driven selection schemes.

Technical Abstract: Identification of markers linked to genes for sprouting tolerance (independent of grain color) in hard white winter wheat (HWWW) ABSTRACT Pre-harvest sprouting (PHS) of wheat (Triticum aestivum L.) can negatively impact end-use quality and seed viability at planting. Due to preferences for white over red wheat in international markets, white wheat with PHS tolerance has become increasingly desired for worldwide wheat production. In general, however, red wheat is more tolerant of sprouting than white wheat. The main objective of this study was the identification of PHS tolerance conditioned by genes donated from hard red winter wheat, using markers applicable to the Great Plains hard white wheat gene pool. Three red wheat by white wheat populations, Niobrara/NW99L7068, NE98466/NW99L7068 and Jagalene/NW99L7068 were developed, white-seeded progeny were both analyzed for PHS tolerance and used to identify markers for the trait. In the three populations, marker loci with significant allelic effects were most commonly located on chromosomes of group 2, 3, 4 and 5, though additional markers were detected across the wheat genome. Chromosome 3A was the only chromosome with significant markers in all three populations. Markers were inconsistent across the three populations, and markers linked to tolerance-inducing loci were identified in both tolerant and susceptible parents. Additive effects of marker loci were common. In the present investigation, a wide range of PHS tolerance was observed, even though all lines were fixed for the recently reported positive TaPHS1 allele. PHS tolerance is controlled by additive major gene effects with minor gene effects where variations of minor gene effects were still unclear.