Genome-Wide Association Study of Grain Architecture in Wild Wheat Aegilops tauschii

Abstract

Aegilops tauschii, the D-genome progenitor of Triticum aestivum, encompasses huge diversity for various traits of potential economic importance such as yield, biotic and abiotic stress tolerance, quality and nutrition. In the present study, variation for grain size in Ae. tauschii germplasm was studied and its genetic basis dissected using genome-wide association study (GWAS). Grain length, width, and weight evaluated in 177 Ae. tauschii accessions over 3 years showed near normal distribution with 1.74-, 1.75-, and 2.82-fold variation, respectively. These lines were genetically characterized using genotyping-by-sequencing (GBS) protocol that produced 11,489 single nucleotide polymorphic (SNP) markers. Genetic diversity analysis revealed the presence of two distinct subgroups (designated as lineage 1 and 2) in Ae. tauschii. Based on GBS markers, the genetic similarity was calculated between the accessions and GWAS was conducted using 114 non-redundant accessions and 5,249 SNP markers. A total of 17 SNPs associated with grain size traits distributed over all the seven chromosomes were revealed with 6D, 5D, and 2D harboring most significant marker–trait associations. Some of the chromosomal regions such as 6D_66.4–71.1 cM, 1D_143.5–156.7 cM, and 2D_89.9–92.5 cM had associations with multiple traits. Candidate genes associated with cell division and differentiation were identified for some of the associated SNP markers. Further efforts to validate these loci will help to understand their role in determining grain size and allelic diversity in current germplasm and its effect on grain size upon transfer to bread wheat background.

Fine mapping qGL2H, a major locus controlling grain length in barley (Hordeum vulgare L.)

“…A promising candidate for the control of grain length is HORVU2Hr1G089310 which encodes a MYB transcription factor protein of subgroup 15. Previous research in other cereal species has indicated that transcription factors are heavily involved in the control of grain size through regulation of cell proliferation and differentiation (Arora et al 2017;Gong et al 2018;Ji et al 2019;Qi et al 2018). Specifically, a MYB transcription factor designated GL4 was shown to regulate cell elongation in the outer and inner glumes of African rice which directly regulated grain length (Wu et al 2017).…”

A reductionist approach to dissecting grain weight and yield in wheat

“…Recent genetic studies have shown the potential for these wild species to provide useful genetic variation for grain weight that could possibly have been excluded from the gene pool during domestication (Golan et al ; Arora et al ; Avni et al ). The genome sequences and other genomic resources now available for many of these progenitor species and landraces will aid the identification of these novel genes and alleles (Avni et al ; Luo et al ; Wingen et al ).…”

Phenotypic and Genotypic Evaluation of Synthetic Hexaploid Wheat Lines (Aabbdd) for Grain Parameters Under the Conditions of Western Siberia

“…Доказана значительная генетическая и фенотипическая вариабельность образцов Ae. tauschii по размерам и массе зерновки в сравнении с мягкой пшеницей (11,19). Более широкий полиморфизм по локусам, контролирующим размер, форму и массу зерна, наблюдается и у синтетической гексаплоидной пшеницы с геномом D от различных образцов Ae.…”

“…В оба года исследований отмечалась положительная сопряженность урожайности с длиной, площадью, периметром зерновки и негативная связь -с показателями качества зерна (содержание белка и клейковины). В то же время нами установлена несущественная связь между длиной и шириной зерновки (r от 0,08 до 0,23), что согласуется с данными других работ (18,19). Следовательно, отбор синтетических линий с более широкой и округлой зерновкой позволит выделить высокопродуктивные генотипы синтетической пшеницы для направления селекции на урожайность.…”