Natural Diversity and Genetic Control of Fruit Sensory Quality - Fruit Ripening: Physiology, Signalling and Genomics - page 236

14

Natural Diversity and Genetic Control of
Fruit Sensory Quality

Bénédicte Quilot-Turion and Mathilde Causse*
INRA, Unité de Génétique et Amélioration des Fruits et Légumes,
Domaine Saint-Maurice, Montfavet Cedex, France

14.1 Introduction

presents their genetic diversity and
inheritance. The genetic basis of fruit
quality traits has been studied in several
progenies and we will summarize the
information provided by quantitative trait
loci (QTLs) studies. The major genes/QTLs
identifi ed as being involved in fruit quality
will be described before presentation of the
future prospects offered by the new high-
throughput genomic approaches available
today. Many studies concern tomato fruit
quality, which is both a model species for
fruit quality studies and an important crop.
Nevertheless, the number of studies on
fruit quality concerning other species is
increasing rapidly.

Fruit sensory quality has only recently
become a target for breeders. Due to
consumer dissatisfaction relating espe-
cially to fruit fl avour, genetic improvement
of this quality is now required (Ulrich and
Olbricht, 2011). Fruit sensory quality is a
complex trait that contributes a com-
bination of fl avour and texture com-
ponents, together with general fruit
appearance attributes. Most sensory traits
are diffi cult to measure by methods other
than sensory analysis. However, some of
the major components of fl avour and
texture such as sweetness, sourness or fruit
fi rmness can be assessed by physical or
chemical measurements (Baldwin et al. ,
1998). The complexity of fruit quality (due
to the number of parameters to take into
account, their polygenic inheritance and
their multiple interactions) and generation
length for fruit trees has limited genetic
progress. Today, molecular markers enable
dissection of the genetic basis of complex
traits, and our increasing knowledge about
the genomes offer new and effi cient tools
to breeders.
This chapter fi rst briefl y describes the
quality components considered and then

14.2 Quality Components

Flavour can be divided into two categories:
the fi rst being taste. Taste is often
described by the sweetness and sourness of
fruit, which are related to the amount of
sugars and organic acids (Stevens et al. ,
1977; Janse and Schols, 1995; Malundo et
al. , 1995), and are also related to their
balance (Stevens et al. , 1979; Bucheli et al. ,
1999). Sugars and acids represent about 60
and 70% of the dry matter weight,