Spelt Genes Could Help Breeders Develop Healthier Wheat Varieties

Spelt wheat and common bread wheat are closely related, yet their genetic make-up differs in a number of respects. Spelt retains particularly high genetic diversity and has characteristics that make it well suited to low-input and organic farming systems. This makes it interesting not only as a food crop: its gene pool could also serve as a valuable genetic resource for wheat breeding.

The researchers were primarily interested in the genetic factors underlying the levels of individual dietary fibre components in wheat grain. They examined three important soluble fibre components: water-extractable pentosans, β-glucan and fructans. The levels of these components can be influenced not only by the genetic background of the wheat but also by environmental conditions, making the identification of relevant genetic variants particularly important for targeted breeding.

The study included a total of 255 genotypes originating from 28 countries: 169 spelt wheat genotypes, 73 bread wheat genotypes and 13 wild hexaploid accessions. The researchers examined the plants’ DNA at tens of thousands of positions and then used a genome-wide association study (GWAS) to identify genetic variants associated with the levels of the individual fibre components. The most important associations were also evaluated in a smaller subset using data from two consecutive years.

The results also revealed an interesting difference between the two types of wheat. Although total pentosan content was similar in spelt and bread wheat, spelt contained, on average, lower levels of water-extractable pentosans, β-glucan and fructans. The lower fructan content may be particularly relevant for people with irritable bowel syndrome (IBS), as spelt could potentially provide a useful raw material for the development of low-FODMAP products.

Another important outcome of the study was the identification of 16 diagnostic SNP markers characteristic of spelt. SNPs are genetic variations affecting a single ‘letter’ of the DNA sequence. By analysing the newly identified markers together, genetically homogeneous spelt and bread wheat lines can be reliably distinguished. This could provide a useful tool both for identifying accessions held in gene banks and for breeding programmes, while also helping to prevent food fraud in the future.

The study therefore goes beyond simply asking whether spelt or bread wheat contains more fibre. The findings could improve our understanding of the genetic factors that determine the levels of important fibre components in wheat grain. In the future, the genetic markers identified could also help breeders select plants with desirable traits more precisely, thereby contributing to improvements in the nutritional quality of wheat varieties.