© Benaki Phytopathological Institute
Margaritopoulou & Milioni
40
a step-change in speed and cost-effective-
ness (Robinson
et al.,
2014). The availabili-
ty of dense genetic maps can facilitate re-
searchers to perform flexible marker-trait
associations, concerning the correlations
between pathogen resistance and alterna-
tive genes, and develop high performance
markers that will promote marker- assisted
choice (MAS) selection for resistant popu-
lations in segregating breeding programs
(Ben-Ari and Lavi, 2012).
Herein, the molecular advances on agri-
cultural crop improvement to meet current
cultivating demands are reviewed for three
economically important crops worldwide,
i.e. sunflower, maize, potato.
Sunflower (Helianthus annuus L.,
Asteraceae)
Sunflower is the foremost seed crop cul-
tivated within the world (Fernández-Luque-
ño
et al.,
2014). Sunflower oil contains less
than 11% total saturated fat and does not
contain any trans fat. Inexpensive produc-
tion of biofuel from sunflower oil has been
achieved (Boumesbah
et al.,
2015). Further-
more, sunflower is an ideal plant for produc-
ing high quality rubber from its leaves and
stems and some of the taller perennial spe-
cies have high latex yield potential (Lu and
Hoeft, 2009).
The multiple usages of sunflower prod-
ucts in food, feed, and industry are stimu-
lating the discovery of new sources of bio-
diversity for sunflower molecular breeding
programs in combination with the appli-
cation of high throughput approaches and
genetic manipulation. The primary objec-
tive for sunflower breeders it to increase
the yield and agronomical performance
of high oleic sunflower hybrids. To accom-
plish these goals, breeders need to ad-
dress pathogens, pests, and environmen-
tal constraints that have the potential to
drastically reduce yield where sunflowers
are grown (Dimitrijevic and Horn, 2018).
Genomic resources
A rich and various germplasm assort-
ment is the backbone of each crop improve-
ment program. Assessing genetic diversi-
ty within a genetic pool of novel breeding
germplasm could make crop improvement
more efficient by the directed accumulation
of desired alleles (Darvishzadeh
et al.,
2010).
Several bacterial artificial chromosome
(BAC) libraries have been constructed for
sunflower (Feng
et al.,
2006; Gentzbittel
et
al.,
2002; Özdemir
et al.,
2004). The libraries
are equivalent to approximately 8 haploid
genomes of sunflower and provide a great-
er than 99% probability of obtaining a clone
of interest and they have been employed for
isolating and physical mapping of loci such
as the FAD2-1 locus (Schuppert
et al.,
2006)
or the fertility restorer Rf1 locus (Hamrit
et
al.,
2008).
In situ
hybridization techniques
involving Fluorescent In Situ Hybridization
(FISH) and BAC-FISH have being optimized
for diversity and biological process studies
between species of the genus Helianthus
and development of a physical helianthus
map allowing a cross reference to the ge-
netic map (Giordani
et al.,
2014).
Various EST sequencing programs have
been carried out in sunflower, including
the Compositae Genome Project, and oth-
er programs (Tamborindeguy
et al.,
2004)
and (Ben
et al.,
2005). The Compositae Ge-
nome Program
-
davis.edu/index.php) has developed and
is utilizing a 2.6 million feature Affymetrix
chip based on 87,000 unigenes from seven
Helianthus
spp. (Lai
et al.,
2012). Interesting
associations have been detected between
Expressed Sequence Tags (ESTs) and Quanti-
tative Trait Loci (QTLs) for salt tolerance and
for domestication traits (Lai
et al.,
2005). Un-
til today, 94.33 % of HA412-HO ESTs are cor-
rectly mapped and 90,935 protein coding
genes are predicted, excluding transposable
elements (
.
org
). Extensive genotyping has been per-
formed for vegetative and flower sunflower
organs together with uncovering gene net-
works for oil metabolism and flowering time
(Badouin
et al.,
2017; Renaut 2017).
Efficient breeding strategy development
Biotechnology has the potential to help
