Detection of QTLs in a Mediterranean climate associated with fire blight necrosis length in Pyrus communis using a high‐resolution genetic linkage map

Abstract

Fire blight caused by the bacterium Erwinia amylovora, is the most critical disease of European pear. Breeding of resistant cultivars is a possible solution for a growing demand for healthier alternative practices for disease control. In this study, we present a pear fire blight genetic study using a large F1 population. Quantitative trait loci (QTLs) were detected using a high‐resolution genetic map, allowing detection of QTLs with small intervals. A total of 162 offspring crossbred between ‘Harrow Sweet’ (HS, low susceptibility cultivar) and ‘Spadona’ (SPD, high susceptibility cultivar) were studied. We detected a significant genotype effect (p < .0001), which explained 46.4% of the variance of the necrosis length. A major QTL of the main genotype effect (AVG) was detected at 8.8 cM in linkage group (LG) 2 (LOD = 7.7). Additional QTLs were detected in LGs 7, 13 and 15. These markers can greatly contribute to pear breeding programs in a Mediterranean climate and can shed light on potential candidate genes that control fire blight resistance.

Genetic and molecular regulation of chilling requirements in pear: breeding for climate change resilience

“…Climate change may influence plants through direct or indirect changes in dormancy. Over the past few decades, multiple global and regional climate models have identified the Mediterranean as a "Hot-Spot" for forecasting future climate changes in temperate regions (Giorgi et al, 2001;Saadi et al, 2015;Gabay et al, 2021). Hence, the current growing conditions in the Mediterranean will be similar to the growing conditions in temperate regions several decades from now.…”

“…However, even for those cultivars, the CRs are not always fulfilled, resulting in delayed VB time that can affect productivity and fruit quality. Considering this, a current project is focused on performing a QTL analysis associated with abiotic and biotic (Gabay et al, 2021) stresses using an F 1 population of European pear 'Spadona' (Low CRs cultivar) and 'Harrow Sweet' (High CRs cultivar) (SPD × HS). Currently, a fruit quality QTL study is being analyzed based on fruit quality trait measurements under a Mediterranean climate in Bet Dagan, Israel, for 2 years (2017)(2018).…”

“…The completion of pear whole-genome sequencing (Wu et al, 2013;Chagnéet al, 2014) provided a valuable genomic resource. The availability of the pear genome has enabled the carrying out of genome-wide association studies (GWAS), greatly contributing to the development of genetic markers, and helping to reveal the genetic mechanisms underlying important agricultural traits (Kumar et al, 2017;Gabay et al, 2018Gabay et al, , 2021Zurn et al, 2020;Zhang et al, 2021). The genetic maps constructed for pears consist of 17 linkage groups (LGs), mirroring the 17 chromosomes in pears (Kumar et al, 2017;Gabay et al, 2018;Zhang et al, 2021).…”