Mapping QTLs for enhancing early biomass derived from Aegilops tauschii in synthetic hexaploid wheat

Abstract

Strong early vigour plays a crucial role in wheat yield improvement by enhancing resource utilization efficiency. Synthetic hexaploid wheat (SHW) combines the elite genes of tetraploid wheat with Aegilops tauschii and has been widely used in wheat genetic improvement for its abundant genetic variation. The two SHWs Syn79 and Syn80 were derived from the crossing of the same tetraploid wheat DOY1 with two different Ae. tauschii accessions, AT333 and AT428, respectively. The Syn80 possessed better early vigour traits than Syn79, theretically caused by their D genome from Ae. tauschii. To dissect their genetic basis in a hexaploid background, 203 recombinant inbred lines (RILs) derived from the cross of Syn79 x Syn80 were developed to detect quantitative trait loci (QTL) for four early biomass related traits: plant height (PH), tiller number (TN), shoot fresh weight (SFW) and shoot dry weight (SDW) per plant, under five different environmental conditions. Determined from the data of SNP markers, two genome regions on 1DS and 7D were stably associated with the four early biomass related traits showing pleiotropic effects. Four stable QTLs QPh.

Genome-Wide Association Mapping of Seedling Vigor and Regrowth Vigor in Winter Wheat

“…In the present study, two single-locus mixed models, MLM and CMLM, and one multilocus mixed model, MLMM, were used to map QTL and identify SNP markers associated with seedling vigor and regrowth vigor traits. Morphological traits, such as shoot length, number of shoots and shoot dry weight, have been used previously to evaluate plant or seedling vigor in different crops, including wheat [10] and rice [15,26,27]. In the present study, winter wheat lines in the wheat diversity panel showed significant phenotypic variation in shoot length, number of shoots and shoot dry weight from both the initial growth and the regrowth of the plants.…”

“…However, seedling vigor and regrowth vigor are genetically complex traits, controlled by minor genes spread across the genome, and they are associated with different plant growth and developmental traits, ranging from cell level to whole plant [7]. Seedling vigor correlates with coleoptile length, shoot length, number of shoots per plant and shoot dry weight [4,[8][9][10]. Both seedling vigor and regrowth vigor are influenced by genotype, environmental conditions and genotype-environment interaction.…”

“…To date, some QTL studies have been conducted to map quantitative trait loci (QTL) for seedling vigor traits in wheat (Triticum aestivum L.) [11][12][13], sorghum (Sorghum bicolor L. Moench) [14] and rice (Oryza sativa L.) [15] using different types of mapping populations, including bi-parental mapping population. In wheat, QTL associated with seedling vigor traits, such as shoot length, number of shoots per plant and shoot dry weight have been found on chromosomes 1D, 2A, 2B, 2D, 3A, 4B, 6A, and 7D [10,[16][17][18]. However, the regrowth vigor of wheat has rarely been studied.…”

Allopolyploidization Enhances Genetic Recombination of the Ancestral Diploid Genome in the Evolution of Wheat

“…tauschii and gene annotation for whole genome reveals that the diploid progenitor of hexaploid wheat D genome serves as a gene repertoire for modern wheat adaptation, which provides possible resistance to disease and pest, tolerance to environmental stresses and grain quality [22,23]. Importantly, these gene could be expressed normally in a hexaploid genetic background, for that lots of related QTLs or genes had been mapped to D genome of synthetic hexaploid wheat [24,[30][31][32][26][27][28][29][36][37]41,42,74]. Moreover, the mRNA and small RNA transcriptomes analysis in nascent hexaploid wheat also demonstrate the heterosis generating in the common wheat [4].…”

“…Ae. tauschii serves as a gene repertoire for modern wheat adaptation [4,22,23], due to their superiority in resistances to disease [24][25][26][27][28][29] and pest [30][31][32], tolerance to environmental stresses [33][34][35][36][37], and yield enhancement [38][39][40][41][42], all of which could be gathered in hexaploid wheat via heterosis theoretically.…”