Frequency of genotypes with missing data (left), and frequency of DArTseq SNPs (loci) with missing data (right).

<p>Frequency of genotypes with missing data (left), and frequency of DArTseq SNPs (loci) with missing data (right).</p

DArTseq markers with high association with eight agronomic traits of 93 wheat genotypes evaluated under drought-stressed and non-stressed conditions.

<p>DArTseq markers with high association with eight agronomic traits of 93 wheat genotypes evaluated under drought-stressed and non-stressed conditions.</p

Genome-wide association analysis of agronomic traits in wheat under drought-stressed and non-stressed conditions

<div><p>This study determined the population structure and genome-wide marker-trait association of agronomic traits of wheat for drought-tolerance breeding. Ninety-three diverse bread wheat genotypes were genotyped using the Diversity Arrays Technology sequencing (DArTseq) protocol. The number of days-to-heading (DTH), number of days-to-maturity (DTM), plant height (PHT), spike length (SPL), number of kernels per spike (KPS), thousand kernel weight (TKW) and grain yield (GYLD), assessed under drought-stressed and non-stressed conditions, were considered for the study. Population structure analysis and genome-wide association mapping were undertaken based on 16,383 silico DArTs loci with < 10% missing data. The population evaluated was grouped into nine distinct genetic structures. Inter-chromosomal linkage disequilibrium showed the existence of linkage decay as physical distance increased. A total of 62 significant (<i>P</i> < 0.001) marker-trait associations (MTAs) were detected explaining more than 20% of the phenotypic variation observed under both drought-stressed and non-stressed conditions. Significant (<i>P</i> < 0.001) MTA event(s) were observed for DTH, PHT, SPL, SPS, and KPS; under both stressed and non-stressed conditions, while additional significant (<i>P</i> < 0.05) associations were observed for TKW, DTM and GYLD under non-stressed condition. The MTAs reported in this population could be useful to initiate marker-assisted selection (MAS) and targeted trait introgression of wheat under drought-stressed and non-stressed conditions, and for fine mapping and cloning of the underlying genes and QTL.</p></div

Genome wide significant associations (R²) of single nucleotide polymorphisms (SNPs) with amylose content (AC), alkali spreading value (ASV), grain width (GW) and grain length to width ratio (L/W).

<p>Genome wide significant associations (R²) of single nucleotide polymorphisms (SNPs) with amylose content (AC), alkali spreading value (ASV), grain width (GW) and grain length to width ratio (L/W).</p

Adult plant resistance to leaf rust and stem rust of wheat in a newly developed recombinant inbred line population

<p>Leaf rust caused by <i>Puccinia triticina</i> and stem rust by <i>P. graminis</i> f. sp. <i>tritici</i> are the most destructive diseases of wheat (<i>Triticum aestivum</i> L.), resulting in substantial yield losses globally. A continuous search for new sources of effective rust resistance genes is necessary to develop improved cultivars with durable resistance. This study aimed to investigate inheritance of adult-plant resistance in a recombinant inbred line (RIL) population of a cross between wheat cultivars ‘Popo’ and ‘Kariega’, and to identify breeding lines possessing both leaf rust and stem rust resistance. A panel of 179 RILs, two parental cultivars and three checks were evaluated in South Africa at two localities, Cedara and Tygerhoek, in 2014 and 2015. Disease response ranged from highly resistant to highly susceptible. Analysis of variance indicated highly significant (<i>p</i> < 0.001) differences among the RILs for both diseases across the testing environments. Broad-sense heritability estimates were 0.53 and 0.77 for leaf rust and stem rust, respectively. Twenty-six RILs were selected showing significantly higher levels of resistance to both pathogens. The moderate to high heritability estimates for leaf rust and stem rust resistance favours the use of the newly developed RILs for resistance breeding against the two diseases.</p

Magnitude of Δ K as a function of Delta K for 59 rice genotypes based on 525 polymorphic DArTseq-derived SNP markers.

<p>Magnitude of Δ K as a function of Delta K for 59 rice genotypes based on 525 polymorphic DArTseq-derived SNP markers.</p

Broad sense heritability estimates for nine phenotypic traits of 96 wheat genotypes evaluated in two localities over two seasons, under two water regimes and two replications.

<p>Broad sense heritability estimates for nine phenotypic traits of 96 wheat genotypes evaluated in two localities over two seasons, under two water regimes and two replications.</p

3D scatter plot of principal component analysis for 59 rice genotypes based on DArTseq-derived SNP markers.

<p>3D scatter plot of principal component analysis for 59 rice genotypes based on DArTseq-derived SNP markers.</p

Distribution pattern of 59 rice genotypes based on Bayesian clustering method of DArTseq derived-SNP markers.

<p>Distribution pattern of 59 rice genotypes based on Bayesian clustering method of DArTseq derived-SNP markers.</p

Nine genetic clusters with their respective list of wheat genotypes, proportion of membership, expected heterozygosity and the mean values of Fst observed from the study population.

<p>Nine genetic clusters with their respective list of wheat genotypes, proportion of membership, expected heterozygosity and the mean values of Fst observed from the study population.</p