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ARS Home » Pacific West Area » Pullman, Washington » Plant Germplasm Introduction and Testing Research » Research » Research Project #437132

Research Project: Identification of Resistance to Ascochyta Blight (Mycosphaerella Pinodes) in the USDA Pea Single Plant-Derived (PSP) Core Collection

Location: Plant Germplasm Introduction and Testing Research

Project Number: 2090-21000-032-015-S
Project Type: Non-Assistance Cooperative Agreement

Start Date: Jun 27, 2019
End Date: Dec 31, 2021

Objective: (1) to screen the PSP for resistance to M. pinoides in pure culture in controlled conditions and (2) use the resulting phenotypic data in combination with already existing genotypic data to identify marker-trait associations using a GWAS approach.

Objective 1: Phenotypic data collection: The PSP collection will be phenotyped for Ascochyta blight (Mycosphaerella pinodes) disease severity at North Carolina State University. The PSP comprises approximately 330 lines, each line was derived from a single plant from the USA core collection. Plants will be grown in controlled conditions in a Phytotron chamber that can accommodate 288, 4.5” pots. The experiment will be conducted twice. Objective 2: Genome-Wide Association Studies: To map quantitative trait loci (QTL) associated with Ascochyta Blight resistance we will use already existing genotype data for the PSP collection. Marker-trait associations (MTAs) will be identified using TASSEL 5.0 and GAPIT (Bradbury et al. 2007; Lipka et al. 2012; Tang et al. 2016) following Richards et al. (2017). The software STRUCTURE v.2.3.4 will be used to determine the population structure (Pritchard et al. 2000). Principal components analysis (PCA) will be conducted using the R package GAPIT. The models used will include mixed linear model MLM + K, plus four additional models accounting for population structure and kinship (Q + K, PC + K, Q + Kcomp, and PC + Kcomp), analyzed as an MLM with Q and PC as fixed effects and kinship as a random effect in GAPIT. Identified MTAs will be deposited in the GRIN database.