Author: Jesse Poland

Genome-wide association mapping for leaf tip necrosis and pseudo-black chaff in relation to durable rust resistance in wheat

Philomin Juliana Jessica Rutkoski Jesse Poland Ravi Singh Mark Sorrells (2015)

The partial rust resistance genes lr34 and sr2 have been used extensively in wheat (triticum aestivum l.) improvement, as they confer exceptional durability. Interestingly, the resistance of lr34 is associated with the expression of leaf tip necrosis (ltn) and sr2 with pseudo-black chaff (pbc). Genome-wide association mapping using cimmyt’s stem rust resistance screening nursery (srrsn) wheat lines was done to identify genotyping-by-sequencing (gbs) markers linked to ltn and pbc. Phenotyping for these traits was done in ithaca, new york (fall 2011); njoro, kenya (main and off-seasons, 2012), and wellington, india (winter, 2013). Using the mixed linear model (mlm), 18 gbs markers were significantly associated with ltn. While some markers were linked to loci where the durable leaf rust resistance genes lr34 (7ds), lr46 (1bl), and lr68 (7bl) were mapped, significant associations were also detected with other loci on 2bl, 5b, 3bs, 4bs, and 7bs. Twelve gbs markers linked to the sr2 locus (3bs) and loci on 2ds, 4al, and 7ds were significantly associated with pbc. This study provides insight into the complex genetic control of ltn and pbc. Further efforts to validate and study these loci might aid in determining the nature of their association with durable resistance.


Partial Rust Resistance Genes Genome Wide Association Mapping Leaf Tip Necrosis Wheat CIENCIAS AGROPECUARIAS Y BIOTECNOLOGÍA

Unlocking the novel genetic diversity and population structure of synthetic Hexaploid wheat

Madhav Bhatta Alexey Morgounov Jesse Poland Peter Stephen Baenziger (2018)

Synthetic hexaploid wheat (shw) is a reconstitution of hexaploid wheat from its progenitors (triticum turgidum ssp. Durum l.; Aabb x aegilops tauschii coss.; Dd) and has novel sources of genetic diversity for broadening the genetic base of elite bread wheat (bw) germplasm (t. Aestivum l). Understanding the diversity and population structure of shws will facilitate their use in wheat breeding programs. Our objectives were to understand the genetic diversity and population structure of shws and compare the genetic diversity of shws with elite bw cultivars and demonstrate the potential of shws to broaden the genetic base of modern wheat germplasm. The genotyping-by-sequencing of shw provided 35,939 high-quality single nucleotide polymorphisms (snps) that were distributed across the a (33%), b (36%), and d (31%) genomes. The percentage of snps on the d genome was nearly same as the other two genomes, unlike in bw cultivars where the d genome polymorphism is generally much lower than the a and b genomes. This indicates the presence of high variation in the d genome in the shws. The d genome gene diversity of shws was 88.2% higher than that found in a sample of elite bw cultivars. Population structure analysis revealed that shws could be separated into two subgroups, mainly differentiated by geographical location of durum parents and growth habit of the crop (spring and winter type). Further population structure analysis of durum and ae. Parents separately identified two subgroups, mainly based on type of parents used. Although ae. Tauschii parents were divided into two sub-species: ae. Tauschii ssp. Tauschii and ssp. Strangulate, they were not clearly distinguished in the diversity analysis outcome. Population differentiation between shws (spring_shw and winter_shw) samples using analysis of molecular variance indicated 17.43% of genetic variance between populations and the remainder within populations. Shws were diverse and had a clearly distinguished population structure identified through gbs-derived snps. The results of this study will provide valuable information for wheat genetic improvement through inclusion of novel genetic variation and is a prerequisite for association mapping and genomic selection to unravel economically important marker-trait associations and for cultivar development.


Genetic variation Hexaploidy Wheats Aegilops Tauschii D-Genome Diversity Genotype-By-Sequencing Single Nucleotide Polymorphism Bread Wheat AEGILOPS SOFT WHEAT TRITICUM TURGIDUM DNA SEQUENCE AGRICULTURAL SCIENCES AND BIOTECHNOLOGY CIENCIAS AGROPECUARIAS Y BIOTECNOLOGÍA

Aerial High-Throughput Phenotyping Enabling Indirect Selection for Grain Yield at the Early-generation Seed-limited Stages in Breeding Program - data for publication

Suchismita Mondal Jose Crossa Ravi Singh Jesse Poland (2020)

The files contain pedigree information on lines used in the study, trait data for grain yield, spectral traits and other agronomic data and genotypic data