Phenotyping and identification of target traits for de novo domestication of wheat wild relatives

Abstract

De novo domestication—the modification of domestication genes in crop wild relatives via genome editing—is an approach for harnessing the beneficial genetic diversity of crop wild relatives. A prerequisite for de novo domestication is phenotyping to identify genetic materials suitable for cultivation in the respective environment. Taxa from the wheat genepool (Triticum aestivum, Triticum durum, Triticum monococcum) are a staple food; these taxa comprise wild relatives of different ploidy levels. The diploid Triticum boeoticum and Triticum urartu and the tetraploid Triticum dicoccoides and Triticum araraticum harbor desirable traits such as high grain quality and abiotic and biotic stress tolerance. Hence, they are candidates for de novo domestication. Here, we grew 111 wild wheats and 38 landraces originating predominantly from the Fertile Crescent and six modern wheat cultivars in a field in Giessen, Germany, to evaluate their environmental adaptability to the central European climate and to identify potential candidates and target traits for de novo domestication. We demonstrate that several wild taxa are suitable for cultivation in the central European environment and that they have distinct characteristics that need to be modified during de novo domestication. The normalized difference vegetation index and the thermal time to heading and flowering indicated excellent adaptability of some wheat wild relatives to central European conditions. The values of yield parameters such as grain weight per plant, number of tillers, and thousand kernel weight were lower in the wild wheats than in the landraces. Therefore, these traits should be targeted for improvement during the de novo domestication of wild wheats.

Grain quality traits within the wheat (Triticum spp.) genepool: prospects for improved nutrition through de novo domestication

“…For the correlation and principal component analysis (PCA), we added the grain weight per plant and thousand kernel weight (TKW) reported in our previous study. 32 Statistics were performed in R Studio with R, version 4.2.0 (www.r-project.org). The emmeans (https://cran.r-project.org/web/packages/emmeans/index.html), multcomp (https://cran.r-project.org/web/packages/multcomp/ index.html) and nlme (https://cran.r-project.org/web/packages/ nlme/index.html) packages were used for the ANOVA, and the FactoMineR (https://cran.r-project.org/web/packages/FactoMin eR/index.html), factoextra (https://cran.r-project.org/web/pack ages/factoextra/index.html) and corrplot (https://cran.r-project.…”

“…Furthermore, among the wild wheats, T. araraticum is suitable for cultivation and exhibits favorable yield parameters. 32 Therefore, T. araraticum and T. zhukovskyi should be considered as sources for developing more nutritious wheat cultivars.…”

“…Plants were harvested individually during July and August. Specific descriptions of the cultivation method have been provided previously 32 . For each genotype, two plants, one from each block, were used as biological replicates.…”

“…Hulled grain samples were threshed as previously described. 32 Whole-grain samples were ground for 2 min at a frequency of 30 Hz at a mill (Mill MM400; RETSCH, Haan, Germany). Wolfram carbide containers were used to prevent iron contamination.…”

“…We previously proposed genes linked to cultivation, harvest and yield for wild wheat de novo domestication. 32 When assessing differences in grain quality between wild and domesticated taxa, the proposed genes should not be edited all at once; rather, a stepwise strategy should be adopted to determine whether any changes in grain quality occur when domestication genes are modified.…”