Construction of a Dense Genetic Linkage Map and Identification of QTLs for Aroma Compounds in the Apple Progeny ‘Kasel-37 X Delbarestivale’

Turkey is one of the apple producer countries in the world. The most important local cultivar in Turkey is ‘Amasya’ which is a very important genetic source with a unique fruit quality. ‘Amasya’ cultivar produces firm, juicy, highly aromatic and long storable fruits, whereas its some characters such as small sized fruits and alternate bearing make it a unpreferable cultivar by the growers. Fruit-tree cultivar breeding programs are time consuming due to their long juvenile periods. Molecular breeding strategy in the breeding programs can reduce time and cost by MAS. In this study, we aimed to identify QTLs for aroma compounds using F1 population of apple cultivars Kasel-37 x Delbarestivale. Kasel-37 is a selection from Amasya. The population had 180 F1 progenies planted in three different locations on M9 rootstocks with two replicates. Firstly, a dense genetic linkage maps of the parents were constructed by SSR, AFLP, E-STS and RGA markers. Kaşel-37 map had 1701.1 cM length containing a total of 621 markers with marker density of 2.9 cM. Delbarestivale map was 1826.7 cM length including a total of 557 markers with one marker per 3.6 cM. The aroma analysis results from gas chromatography were subjected to QTL analysis, and a total of 69 stable QTLs were identified. Most of the detected QTLs were on LG3, LG5, LG8, LG9, LG10 and on LG11. Identification of QTLs for aroma compounds is an important step to discover the genes and eventually enabling marker-assisted breeding in apple.