Association genetics and genomic prediction for resistance to root rot
in a diverse collection of Pisum sativum L.
Abstract
Root rot is one of the most threatening diseases to pea production. Root
rot is caused by several interacting soil-borne pathogens, which makes
it challenging to manage. Breeding for resistance is a promising
approach for sustainable pea production. While quantitative trait loci
(QTL) for resistance against individual pathogens have been identified,
the genetic basis underlying resistance against the pathogen complex is
poorly understood. Using a previously described diverse panel of 254 pea
genotypes and 18k single nucleotide polymorphism (SNP) markers, we
identified a novel QTL for resistance to root rot on chromosome chr6LG2.
This QTL co-locates with a mitochondrial Rho GTPase and an
F-box gene model, which are promising candidates for disease
control. A whole-genome prediction model explained up to 53% of the
phenotypic variation and reached predictive abilities of up to 0.51 for
root rot-related traits. We found that plant height and shoot biomass
were unreliable plant health indicators. Instead, these traits were
related to the Mendelian Le locus, which controls stem length.
Our results provide new insights into the genetic basis of quantitative
root rot resistance in pea and provide novel tools that could accelerate
the development of resistant pea lines through marker-assisted and
genomic selection.