Mining Centuries Old In situ Conserved Turkish Wheat Landraces for Grain Yield and Stripe Rust Resistance Genes

Abstract

Wheat landraces in Turkey are an important genetic resource for wheat improvement. An exhaustive 5-year (2009–2014) effort made by the International Winter Wheat Improvement Programme (IWWIP), a cooperative program between the Ministry of Food, Agriculture and Livestock of Turkey, the International Center for Maize and Wheat Improvement (CIMMYT) and the International Center for Agricultural Research in the Dry Areas (ICARDA), led to the collection and documentation of around 2000 landrace populations from 55 provinces throughout Turkey. This study reports the genetic characterization of a subset of bread wheat landraces collected in 2010 from 11 diverse provinces using genotyping-by-sequencing (GBS) technology. The potential of this collection to identify loci determining grain yield and stripe rust resistance via genome-wide association (GWA) analysis was explored. A high genetic diversity (diversity index = 0.260) and a moderate population structure based on highly inherited spike traits was revealed in the panel. The linkage disequilibrium decayed at 10 cM across the whole genome and was slower as compared to other landrace collections. In addition to previously reported QTL, GWA analysis also identified new candidate genomic regions for stripe rust resistance, grain yield, and spike productivity components. New candidate genomic regions reflect the potential of this landrace collection to further increase genetic diversity in elite germplasm.

Genome Wide Association Study of Resistance to PstS2 and Warrior Races of Stripe (Yellow) Rust in Bread Wheat Landraces

“…and 59% adult plant resistance in three years respectively which is similar to the stripe rust response in Izmir to Turkish landraces reported by Sehgal et al, (2016). The population structure of 600 bread wheat landraces clustered the population into two major clusters mainly from Syrian and Turkish origin with a degree of admixture.…”

“…There is increased use of wheat landraces for the enhancement of genetic diversity and the mining of desirable genes . Therefore, wheat landraces are considered as a key genetic resource for wheat breeding (Sehgal D et al, 2016). Stripe rust caused by Puccinia striiformis f.…”

“…(Akcura et al, 2017). The advantage of these landraces over commercial cultivars is their cultivation over years by local farmers without interference of any scientific breeding methods lead them to adapt changing climatic conditions and evolving disease resistance and therefore it could be expected that the resistance found in these landraces is ought to be more durable and novel (Sehgal et al, 2016). Since the co-evolution of rust pathogens and wheat crop in fertile crescent for thousands of years might be the reason of durable and novel genomic resistance found in the landraces as it has been evident for durability of the transfer of common bunt resistance originated from Turkish landraces to modern cultivars saving millions of dollars for wheat industry (Bonman et al, 2006).…”

Incorporating Genome-Wide Association Mapping Results Into Genomic Prediction Models for Grain Yield and Yield Stability in CIMMYT Spring Bread Wheat

“…QTL with large effects (≥10%) have been identified for less complex traits in wheat (e.g., rust resistance) in bi-parental populations and have been integrated in GS models as fixed effects to improve prediction accuracies (Rutkoski et al, 2014). However, such large effect QTLs are rarely identified for complex traits such as GY in a typical GWAS study (Sehgal et al, 2016(Sehgal et al, , 2017. The potential to integrate consistent and robust associations identified from GWAS as fixed variables in GS models to improve prediction accuracy for complex traits has not been investigated comprehensively in plants (Spindel et al, 2016;He et al, 2016).…”

Towards the Genomic Basis of Local Adaptation in Landraces

“…), the analysis of LA in crop landraces can be also carried out focusing on specific candidate regions or by genome-wide scans (e.g., linkage mapping or genome-wide association studies (GWAS), respectively) [59]. Association mapping in crop landraces (e.g., barley, common bean, soybean, durum, and common wheat) can reveal previously undescribed candidate regions associated with agronomic traits, including biotic stress resistance [70][71][72][73][74][75]. QTL mapping classically requires structured populations (e.g., recombinant populations deriving from phenotypically divergent inbred lines).…”