Mining the Vavilov wheat diversity panel for new sources of adult plant resistance to stripe rust

Multi-year evaluation of the Vavilov wheat diversity panel identified new sources of adult plant resistance to stripe rust. Genome-wide association studies revealed the key genomic regions influencing resistance, including seven novel loci

Standing on the shoulders of giants: Vavilov's wheat collection and sources of resistance

Nikolai Ivanovich Vavilov was a renowned Russian botanist and geneticist, best known for his theory relating to “the centres of origin of cultivated plants”. Inspired by his idol, Charles Darwin, he travelled the world in the early 1900s collecting more seeds, tubers and fruits than any person in history. The collections, including many wheat landraces, were stored in a seed bank in Leningrad, now known as the N. I. Vavilov Institute of Plant Genetic Resources in St Petersburg, Russia. Remarkably, the unique seed collection survived the “Siege of Leningrad” during World War II. However, Vavilov himself faced an ironic fate – he was arrested for criticising the non-Mendelian concepts of a Soviet biologist, Trofim Lysenko, who had the support of Joseph Stalin. Vavilov was sentenced to death in July 1941, but in 1942 his sentence was reduced to 20 years imprisonment. Despite this, he died of starvation in prison in 1943. Following in the footsteps of the Great Russian scientist and his colleagues, we performed the world’s first genetic analysis of Vavilov’s wheat seeds. A total of 295 diverse wheats collected from around the world were examined using 34,000 DNA markers. The genomic analysis revealed a massive array of allelic diversity that is absent in modern germplasm. We provide a summary of our ongoing efforts to discover new genes for disease resistance hidden in the Vavilov treasures. By combining several breeding technologies, we are rapidly mining new sources of resistance to major foliar diseases of wheat, including the rapidly evolving rust diseases (stripe, leaf and stem rust) and yellow spot disease

A multi-reference parent nested-association mapping population to dissect the genetics of quantitative traits in durum wheat

Durum wheat (Triticum durum Desf.) breeding programs face many challenges surrounding the development of stable varieties with high quality and yield. Therefore, researchers and breeders are focused on deciphering the genetic architecture of biotic and abiotic traits with the aim of pyramiding desirable traits. These efforts require access to diverse genetic resources, including wild relatives, germplasm collections and mapping populations. Advances in accelerated generation technologies have enabled the rapid development of mapping populations with significant genetic diversity. Here, we describe the development of a durum Nested Association Mapping (dNAM) population, which represents a valuable genetic resource for mapping the effects of different alleles on trait performance. We created this population to understand the quantitative nature of drought-adaptive traits in durum wheat. We developed 920 F6 lines in only 18 months using speed breeding technology, including the F4 generation in the field. Large variation in above- and below-ground traits was observed, which could be harnessed using genetic mapping and breeding approaches. We genotyped the population using 13,393 DArTseq markers. Quality control resulted in 6,785 high-quality polymorphic markers used for structure analysis, linkage disequilibrium decay, and marker-trait association analyses. To demonstrate the effectiveness of dNAM as a resource for elucidating the genetic control of quantitative traits, we took a genome-wide mapping approach using the FarmCPU method for plant height and days to flowering. These results highlight the power of using dNAM as a tool to dissect the genetics of durum wheat traits, supporting the development of varieties with improved adaptation and yield