Construction of a Genetic Linkage Map and QTL Analysis of Fruit-related Traits in an F1 Red Fuji x Hongrou Apple Hybrid

Abstract

A genetic linkage map of the apple, composed of 175 SSR and 105 SRAP markers, has been constructed using 110 F1 individuals obtained from a cross between the ‘Red Fuji’ Malus domestica and ‘Hongrou’ Malus sieversii cultivars, which have relatively high levels of DNA marker polymorphism and differ remarkably in fruit-related traits. The linkage map comprised 17 linkage groups, covering 1299.67 cM with an average marker distance of 4.6 cM between adjacent markers, or approximately 91% of Malus genome. Linkage groups were well populated and, although marker density ranged from 2.1 to 9.5 cM, just 10 gaps of more than 15 cM were observed. Moreover, just 12.5% of markers displayed segregation distortion. The present genetic linkage map was used to identify quantitative trait loci (QTLs) affecting fruit-related traits. 23 QTLs for ten fruit traits were detected by multiple interval mapping: 3 QTLs for Vc content, One QTL for single fruit weight, 2 QTLs for peel-phenols content, 2 QTLs for flesh-hardness, 2 QTLs for diameter, 6 QTLs for acid content, 1 QTL for sugar content, 2 QTLs for soluble solids content, 2 QTLs for flesh-phenols and 2 QTLs for brittleness. These QTLs were located on linkage groups C1, C2, C3, C5, C6, C7, C9, C10, C14 and C17, respectively. The phenotypic variations exhibited by each QTL ranged from 2% to 72%, and their LOD values varied from 2.03 to 8.93, of which five QTLs were major effect genes (R2 ≥ 10%). The tight linkage markers (*me2em7-460f, *MS01a03-180m, *me1em6-307m, *CH05c06-102f, *me1em8-423f) would be helpful to elucidate the molecular mechanisms of apple domestication and breeding in the future.

Phased diploid genome assemblies and pan-genomes provide insights into the genetic history of apple domestication

“…The cultivated apple inherited its fruit size mainly from M. sieversii 18 . A fruit weight quantitative trait locus (QTL) 34 on chromosome 6 (24–29 Mb) was found in a region surrounded by recombination spots, whereas only the M. sieversii allele was inherited by the cultivated apple (Fig. 3e ), suggesting a strong selection on this region during domestication.…”

Genetic Characterization of the Apple Germplasm Collection in Central Italy: The Value of Local Varieties

“…To date several hundred SSR markers have been developed and mapped in apples by Guilford et al (1997) , Gianfranceschi et al (1998) , Liebhard et al (2002) , Vinatzer et al (2004) , Silfverberg-Dilworth et al (2006) , Han and Korban (2008) , and Celton et al (2009) . Many of these mapped SSR are linked to QTL with interesting agronomical, morphological, and organoleptic traits and could be used as molecular tools for marker assisted selection (MAS) in plant breeding programs ( Gianfranceschi et al, 1998 ; Gygax et al, 2004 ; Kunihisa et al, 2014 ; Sun et al, 2014 ; Liu et al, 2016 ). Microsatellites have been also widely used in apples to asses the genetic diversity in core collections ( Yun et al, 2015 ; Lassois et al, 2016 ; Urrestarazu et al, 2016 ), cultivar characterization ( Goulão and Oliveira, 2001 ; Patzak et al, 2012 ; Pérez-Romero et al, 2015 ), and parentage analysis ( Kitahara et al, 2005 ; Moriya et al, 2011 ; Lassois et al, 2016 ).…”

Morphological observation and characterization of the Pseudoregma bambucicola with the scanning electron microscope

“…Besides, the cornicle of Takecallis taiwanus also is short tube, but the Abdominal tergite I – V each have a pair of tumor. The cornicle of Cetatovacuna silvestrii is conical, the cornicle of Cerataphis bambusifoliae annular and the Abdominal tergite VIII is semilune, the cornicle of Chaitoregma tattakana truncation (Liu et al, 2016, Xie et al, 2016, Fang et al, 2006, Zhao and Ban, 2011). However, the cornicle of P. bambucicola , Hormaphididae, is shorter than others.…”