Natural Diversity and Genetic Control of Fruit Sensory Quality - Fruit Ripening: Physiology, Signalling and Genomics - page 238

Cluster 4

Cluster 3

Sweetness
Aroma
Acid

Size
Mealy

Cluster 2

Cluster 1

Firm
Crunchy

Fig. 14.1. Schematic representation of a preference mapping experiment in tomato. Trained panels and 800
consumers tasted 16 tomato cultivars. The cultivars (stars) are projected on the fi rst multifactorial plan
defi ned by sensory traits. The fi rst axis is defi ned by sweet and acid fl avours and aroma intensity (positive
values) and fruit size and mealiness (negative values). The second axis is defi ned by texture traits. Four
clusters of consumers were identifi ed: consumers of cluster 1 liked many different tomato types; in cluster 2
they preferred the small varieties and appreciated sourness and aroma intensity; and in cluster 3 they liked
small, tasty tomatoes; while in cluster 4 they were mainly looking for melting fruits. Adapted from Sinesio et
al. (2010) and Causse et al. (2010).

during fruit growth (Dorais et al. , 2001),
the maturity stage at harvest (Kader, 2008)
and the conditions during fruit storage
(Stern et al. , 1994).

were frequently used and revealed a high
level of co-ancestry among many modern
cultivars (Noiton and Alspach, 1996).
Wild species, in spite of their un-
favourable characteristics in comparison
with cultivars, can carry alleles that may
contribute to the improvement of most
agronomic traits (de Vicente and Tanksley,
1993; Bernacchi et al. , 1998). Gur and
Zamir (2004) made progress by pyramiding
independent yield-promoting regions intro-
duced from the wild species Solanum
pennellii . Wild species may provide
original aromas, either favourable to tomato
quality, as found in a Solanum peruvianum
accession (Kamal et al. , 2001) or un-
favourable as the Malodorous locus found
in an S. pennellii accession (Tadmor et al. ,
2002).
Genetic variability for quality traits has
been reviewed in tomato by Davies and

14.3 Genetic Variability and Inheritance
of Quality Traits

For a successful breeding programme,
breeders need effi cient selection criteria
and must know the potential for improve-
ment, i.e. the range of genetic variability
available, the mode of inheritance and the
respective infl uence of cultivar and
environmental conditions on the traits to
improve. Breeders tend to use only a few
high-quality parents and thus work with a
reduced genetic diversity. For example, in
apple, a study of the pedigrees of 50
modern cultivars showed that fi ve genitors