Transmission of Fruit Quality Traits in Apricot (Prunus armeniaca L.) and Analysis of Linked Quantitative Trait Loci (QTLs) Using Simple Sequence Repeat (SSR) Markers

Twelve important pomological traits related to fruit quality were studied during 3 years in an F-1 apricot progeny of 160 seedlings derived from a cross between the Spanish selection 'Z701-1' and the South African cultivar 'Palsteyn'. Results indicated quantitative transmission of most of the fruit quality traits studied. In addition, a clear influence of the genetic background of parents was observed. In some seedlings, values outside the range of the parent were observed due to the influence of this genetic background. No correlations were found among most agronomic traits in apricot during the 3 years of the study. However, high correlations between years were described for most of the evaluated traits, and the environment had limited influence on the expression of the trait. A genetic map was developed using 41 apricot and peach SSR markers. The map obtained showed eight linkage groups (corresponding to the eight chromosomes) covering a total distance of 369.3 cM and an average distance between markers of 9 cM. Fifty-four QTLs associated with different traits were identified, including: blooming date (linkage groups G1, G4 and G7); ripening time (G4 and G6); fruit development (G4 and G6); fruit weight (G1 and G4); stone weight (G1 and G7); flesh color (G1 and G6); pH (G1, G2 and G4); malic acid (G1, G2 and G4); and soluble solids content (G4 and G5). We have highlighted several QTLs in G4 that explain the variability in various traits related to fruit quality such as blooming date, ripening time, and soluble solids content. In addition, we have also highlighted an important QTL on G2 that explains much of the variation in levels of acidity.