Inheritance of Fruit Red-Flesh Patterns in Peach

Abstract

Fruit color is an important trait in peach from the point of view of consumer preference, nutritional content, and diversification of fruit typologies. Several genes and phenotypes have been described for peach flesh and skin color, and although peach color knowledge has increased in the last few years, some fruit color patterns observed in peach breeding programs have not been carefully described. In this work, we first describe some peach mesocarp color patterns that have not yet been described in a collection of commercial peach cultivars, and we also study the genetic inheritance of the red dots present in the flesh (RDF) and red color around the stone (CAS) in several intra- and interspecific segregating populations for both traits. For RDF, we identified a QTL at the beginning of G5 in two intraspecific populations, and for CAS we identified a major QTL in G4 in both an intraspecific and an interspecific population between almond and peach. Finally, we discuss the interaction between these QTLs and some other genes previously identified in peach, such as dominant blood flesh (DBF), color around the stone (Cs), subacid (D) and the maturity date (MD), and the implications for peach breeding. The results obtained here will help peach germplasm curators and breeders to better characterize their plant materials and to develop an integrated system of molecular markers to select these traits.

Keywords: Prunus; QTLs; anthocyanins; fruit quality; marker-assisted breeding.

Figure 1

Image of the different flesh color phenotypes identified in the IRTA peach commercial cultivar collection. (A) Yellow flesh (Noracila). (B) White flesh (Nectarnovala). (C) Red flesh (Diablotina). (D) Red dots in the flesh (RDF) (Crispsol). (E) Red dots under the skin (RDS) (Britney Lane). (F) Red color around the stone (CAS) (Lucius).

Figure 2

Maturity date (MD) and red color around the stone (CAS) in IRTA’s peach cultivar collection. (A) Distribution of the MD in Julian days. (B) Contingency table between CAS and MD. In green, percentage of individuals with no CAS, and in blue, percentage of individuals with CAS. In red, the Diablotina cultivar that was not phenotyped for CAS.

Figure 3

Genetic maps and QTLs from Nectalady (Nl) map of the BtxNl population, and SDF2 and T1E maps. Cs is indicated in red. Black bars indicate the LOD-1 interval.

Figure 4

Images of three different individuals from the BbxNl (A) and SDF2 (B) populations showing the different intensities of the RDF phenotype.

Figure 5

Images of different fruit of different T1E individuals with yellow flesh and yellow CAS (T1E003), red flesh and yellow CAS (T1E023), yellow flesh and red CAS (T1E282) and red flesh and red CAS (T1E032).