|IBBA, MARIA ITRIA - Washington State University
Submitted to: Journal of Cereal Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/14/2018
Publication Date: 11/20/2018
Citation: Ibba, M., Kiszonas, A., See, D.R., Skinner, D.Z., Morris, C.F. 2018. Mapping kernel texture in a soft durum (Triticum turgidum ssp. durum) wheat population. Journal of Cereal Science. 85:20-26. https://doi.org/10.1016/j.jcs.2018.10.006.
Interpretive Summary: In the present study QTLs associated with kernel hardness variation were identified for the first time in a durum wheat genetic background. Significant genetic regions were identified on most of the chromosomes with two QTLs on chromosomes 3AL and 6AS being the most significantly associated with kernel hardness. Also, KASP markers targeting these two loci were validated and could be used for QTL validation in different soft durum wheat populations segregating for kernel hardness. Overall, results of this study greatly improve the genetic understanding of kernel hardness variation in durum wheat.
Technical Abstract: Kernel texture (“hardness”) is one of the major determinants of wheat quality. This trait is primarily controlled by the Puroindoline (Pin) genes, located on the short arm of chromosome 5D. Allelic variation of the Pin genes determines major differences in kernel hardness among common wheat (Triticum aestivum) varieties. Conversely, the complete absence of the Ha locus is responsible for the extremely hard kernels typical of durum wheat (Triticum durum). Additional environmental and genetic factors are responsible for minor changes in kernel texture. Recently, the Pin genes from a soft common wheat variety were introgressed into durum wheat through homoelogous recombination. Several soft durum wheat lines were developed and variation in kernel hardness was observed. The objective of this study was to map kernel hardness in a soft durum wheat population derived from the cross between the varieties “Creso” and “Langdon 1-678”. 428 F6 lines were evaluated for kernel hardness through the single kernel characterization system and hardness index (HI) values ranging from -2 to 44 were observed. The same lines were genotyped using both genotyping-by-sequencing, targeted amplicon sequencing and sequence-tagged-site markers. A total of 8537 markers were used to conduct a single marker-trait association analysis and two major significant regions were identified on chromosomes 3AL and 6AS, each responsible for an additive effect of ~ 6 HI units. Kompetitive allele specific markers targeting these regions were selected and tested in the whole population. To date, this is the first study to investigate the genetic factors behind hardness variation in durum wheat.