Most cultivated apple cultivars are highly susceptible to fire blight, caused by Erwinia amylovora. However, differences in resistance levels are observed among cultivars and could be used in breeding. In this paper, we investigated the genetic basis of fire blight resistance of the cultivar âEnterpriseâ and the advanced breeding selection X-6398. Genotyped pedigrees were used for validating and curating historic pedigree records. Various quantitative trait locus (QTL) discovery approaches were applied on the full-sib families âGalaâ Ã âEnterpriseâ (GaEn) and X-6398 Ã X-6683 (IW) with the software FlexQTLâ¢ and MapQTLÂ®. The paternal lineage of âEnterpriseâ was reconstructed and showed to include âCoxâs Orange Pippinâ. The QTLs found varied with the software used. Using FlexQTLâ¢, two were found on linkage groups (LGs) 7 and 13, favourable alleles inherited by Enterprise from âCoxâs Orange Pippinâ and âGolden Deliciousâ, respectively. The former was identical to the previously named FB_F7 allele from âFiestaâ, while the latter is new and has been named FB_13GD. X-6398 had a QTL at the same position as FB_F7. Its favourable allele was new, originating from the unknown grandfather of X-4598, and was named FB_7X-6398. Using MapQTLÂ® on GaEn, FB_F7 was also identified. Performing the same analysis on the subset of offspring that carried the favourable allele of FB_F7, two putative QTLs on LG8 and on top of LG13 were identified, which showed interactions with FB_F7. Implication of the findings for breeding for fire blight-resistant apples is discussed. Single nucleotide polymorphism data on Enterprise and its ancestors are provided.
|Titolo:||Epistatic fire blight resistance QTL alleles in the apple cultivar 'Enterprise' and selection X-6398 discovered and characterized through pedigree-informed analysis|
DI GUARDO, MARIO (Corresponding)
|Data di pubblicazione:||2018|
|Appare nelle tipologie:||1.1 Articolo in rivista|