Molecular Diagnostics for Complex Pest and Disease Resistance and Tuber Quality Traits: Concept, Achievements and Perspectives

Abstract

We summarize the concept of molecular diagnostic of complex traits related to pest and disease resistance and to tuber quality of potato, and describe recent achievements and perspectives. Many potato characteristics are controlled by multiple genetic and environmental factors. Knowing the genes and their allelic variants that underlay these characteristics allows developing molecular diagnostic tools to select for improved potato cultivars. Diagnostic DNA-based markers can be used to identify superior genotypes (precision breeding). Diagnostic markers can be identified by combining quantitative trait locus mapping, candidate gene mapping and association mapping using functional and positional candidate genes as markers. This approach was successfully used to identify loci, which contribute to the natural variation of important agronomic traits, including resistance against root cyst nematodes, late blight and wart disease and tuber quality (resistance to bruising and chip colour). In the future, whole genome association mapping based on single-nucleotide polymorphism genotyping methods in combination with the annotated potato genome sequence will allow identifying additional genes and gene variants controlling agronomic performance in potato. Prerequisites are accurate phenotyping under field conditions of advanced breeding materials, cost-effective and reliable genome-wide genotyping methods, and user-friendly software tools allowing to extract knowledge from massive quantities of data. This will further facilitate molecular diagnosis, selection and combination of superior alleles in potato-breeding programmes.

Genetic Map and QTL Analysis of Agronomic Traits in a Diploid Potato Population using Single Nucleotide Polymorphism Markers

“…Consensus maps could be useful for decreasing the QTL confidence intervals to identify a set of markers for selection of candidate genes in the anchored genome sequence. Likewise, dense genetic maps using transferable markers anchored to the genome sequence could be used as the starting point of a combined strategy with candidate gene and association mapping approaches to identify diagnostic markers for complex traits as proposed by Gebhardt et al (2011). In the present study, the Solanaceae Coordinated Agricultural Project (SolCAP) Infinium 8303 Potato Array was used to build a genetic map of a diploid segregating population.…”