QTL analysis of resistance to sharka disease in the apricot (Prunus armeniaca L.) 'Polonais' X 'Stark Early Orange' F1 progeny

• Published in: Tree genetics & genomes 2007-10, Vol.3 (4), p.299-309
• Main Authors: Lambert, P, Dicenta, F, Rubio, M, Audergon, J M
• Format: Article
• Language: English
• Subjects: Plum pox virus; Prunus; Prunus armeniaca
• ISSN: 1614-2942; 1614-2950
• DOI: 10.1007/s11295-006-0069-6

Different hypotheses on the genetic control of the resistance to the plum pox virus (PPV) have been reported in apricot, but there was a lack of agreement about the number of loci involved. In recent years, apricot genetic maps have been constructed from progenies derived from 'Stark Early Orange' or 'Goldrich', two main sources of resistance, three of these including the mapping of the PPV resistance loci. As the location of the locus was not precisely established, we mapped the PPV resistance loci using interval mapping (IM), composite interval mapping (CIM), and the Kruskal-Wallis non- parametric test in the F sub(1) progeny derived from a cross between the susceptible cv. 'Polonais' and 'Stark Early Orange'. Four genomic regions were identified as being involved in PPV resistance. One of these mapped to the upper region of linkage group 1 of 'Stark Early Orange', and accounted for 56% of the phenotypic variation. Its location was similar to the one previously identified in 'Goldrich' and Prunus davidiana. In addition, a gene strongly associated to these major quantitative trait loci (QTL) was found to be related to PPV infection. Two putative QTLs were detected on linkage groups 3 of 'Polonais' and 5 of both 'Polonais' and 'Stark Early Orange' with both parametric and non-parametric methods at logarithm of odds (LOD) scores slightly above the detection threshold. The last QTL was only detected in the early stage of the infection. PPV resistance is, thus, controlled by a major dominant factor located on linkage group 1. The hypothesis of recessive factors with lower effect is discussed.