QTL mapping of powdery mildew susceptibility in hop (Humulus lupulus L.)
Source: Euphytica, Volume 180, Number 3, August 2011 , pp. 411-420(10)
Abstract:Hop powdery mildew [Podosphaera macularis (Wallr.) U. Braun & S. Takam.] is best controlled via the production of resistant varieties. Recent evidence supports selection against plant susceptibility genes to fungal pathogens as a more durable resistance mechanism than selection for resistance genes. The objective of this study was to identify molecular-based QTLs, their genetic effects and epistasis among QTLs associated with susceptibility to powdery mildew. Parents and offspring from the cross, ‘Perle’ × ‘USDA 19058M’, were clonally replicated and inoculated in a greenhouse using a CRD experimental design in Corvallis, OR. DNA was extracted, purified and analyzed via three different marker systems. Analysis of the resulting markers was based upon the “two-way pseudo-testcross” procedure. QTL mapping using multiple interval mapping and Bayesian interval mapping analyses were performed using WinQTL Cartographer 2.5_003. Comparison amongst mapping analyses identified three persistent QTLs on three linkage groups without significant epistatic effect upon expression. The persistent QTL on linkage group C7 had both additive and dominant effects controlling phenotype expression. The presence or absence of the two AFLP markers bordering the QTL on C7 defined susceptibility in offspring. This is the first report in hop identifying molecular markers linked to QTLs associated with disease susceptibility.
Document Type: Research Article
Affiliations: 1: USDA-ARS-Forage Seed Crop Research Unit, 3450 SW Campus Way, Corvallis, OR, 97331, USA, Email: firstname.lastname@example.org 2: Department of Crop & Soil Sciences, Oregon State University, Corvallis, OR, 97331, USA 3: USDA-ARS-Forage Seed Crop Research Unit, 3450 SW Campus Way, Corvallis, OR, 97331, USA 4: USDA-ARS-NCGR, 33447 Peoria Rd, Corvallis, OR, 97333, USA 5: Hopsteiner, S. S. Steiner, 655 Madison Ave, New York, NY, 10065, USA 6: Plant & Food Research, Auckland Mail Centre, Private Bag 92169, Auckland, 1142, New Zealand
Publication date: 2011-08-01