Firdissa E. Bokore, Richard D. Cuthbert, Ron E. Knox, Heather L. Campbell, Brad Meyer, Amidou N’Diaye, Curtis J. Pozniak & Ron DePauw

Theoretical and Applied Genetics; April 2022; vol. 135: 1143–1162

Key message

A major QTL on chromosome arm 4BS was associated with reduced spike shattering and reduced plant height in coupling phase, and a second major QTL associated with reduced spike shattering was detected on chromosome arm 5AL in the same wheat variety Carberry.

Abstract

Spike shattering can cause severe grain yield loss in wheat. Development of cultivars with reduced shattering but having easy mechanical threshability is the target of wheat breeding programs. This study was conducted to determine quantitative trait loci (QTL) associated with shattering resistance, and epistasis among QTL in the populations Carberry/AC Cadillac and Carberry/Thatcher. Response of the populations to spike shattering was evaluated near Swift Current, SK, in four to five environments. Plant height data recorded in different locations and years were used to determine the relationship of the trait with spike shattering. Each population was genotyped and mapped with the wheat 90 K Illumina iSelect SNP array. Main effect QTL were analyzed by MapQTL 6, and epistatic interactions between main effect QTL were determined by QTLNetwork 2.0. Correlations between height and shattering ranged from 0.15 to 0.49. Carberry contributed two major QTL associated with spike shattering on chromosome arms 4BS and 5AL, detected in both populations. Carberry also contributed two minor QTL on 7AS and 7AL. AC Cadillac contributed five minor QTL on 1AL, 2DL, 3AL, 3DL and 7DS. Nine epistatic QTL interactions were identified, out of which the most consistent and synergistic interaction, that reduced the expression of shattering, occurred between 4BS and 5AL QTL. The 4BS QTL was consistently associated with reduced shattering and reduced plant height in the coupling phase. The present findings shed light on the inheritance of shattering resistance and provide genetic markers for manipulating the trait to develop wheat cultivars.

See: https://link.springer.com/article/10.1007/s00122-021-03980-2

Figure 2: Linkage maps displaying shattering resistance QTL identified in the Carberry/Thatcher (CT) and Carberry/AC Cadillac (CCd) doubled haploid populations. Logarithm of the odds (LOD) values generated by Multiple QTL Mapping (MQM) analysis are presented alongside linkage maps indicating distances in cM between the 90 K SNP wheat iSelect markers (Illumina Inc., San Diego, CA). Co-segregating markers outside of the QTL intervals were removed from the map. Alleles for reduced shattering on chromosomes 4B, 5A and 7A were derived from Carberry and 1A, 2D, 3A, 3D and 7D from AC Cadillac. The map positions of the QTL on 4B and 5A were aligned across both populations. Abbreviations for locations followed by test year are defined as follows: CF, Centre Farm; SF, South Farm; and field name followed by test year: Fld16_2014, Field 16 2014; and Fld17_2018, Field 17 2018.