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been developed. In recent years, several extensive reviews have dealt with this
ample fi eld of basic and applied research (see, e.g., Li and Wang 2009 ; Wang 2011 ;
Mujeeb-Kazi et al. 2013 ; Ceoloni et al. 2014a ; Chaudhary et al. 2014 ). The present
contribution will focus on major achievements and latest advances in gene transfer
from those perennial Triticeae species that have more signifi cantly contributed, or
have the potential, to enhance the breeding performance of cultivated wheat s, both
bread wheat ( Triticum aestivum L., 2 n = 6 x = 42) and durum wheat ( Triticum durum
Desf., 2 n = 4 x = 28), in the light of a changing ecological and socioeconomic agri-
cultural perspective.
11.2 A Brief Survey on the Cytogenomic Makeup
of Perennial Triticeae
Depending on the taxonomic treatment, between 200 and 250 wheatgrass and wild-
rye species have been described worldwide, the majority being native to Eurasia and
a few to North America, but, as a whole, spread and adapted to the most different
environmental conditions of all continents (reviewed in Wang 2011 ). Not differently
from the other representatives of the Triticeae tribe, perennial grasses represent fas-
cinating and puzzling examples of reticulate evolution, in which besides polyploidi-
zation, hybridization and interspecifi c introgression among polyploid lineages and/
or their diploid progenitors played a key role in shaping their genomes (e.g. Mahelka
et al. 2011 ; Mason-Gamer 2013 ; Sun 2014 ). The resulting genomic heterogeneity
has made taxonomic treatment of this ample group of species quite challenging, and
often controversial. Moreover, as for other species groups, rather different criteria
have animated classifi cation systems through the years (e.g. Barkworth et al. 2009 ).
Even the many genetic and cytogenetic approaches used to investigate intra- and
interspecifi c genome relationships, from classical analyses of chromosome pairing
in hybrids, to their “modern” version, with differentially painted genomes, based on
genomic in situ hybridization (GISH), up to the ever increasing use of gene/sequence
comparisons, and of the many other molecular tools recently available, in several
cases still require a thorough interpretation. Thus, although the genome-based clas-
sifi cations proposed by Dewey ( 1984 ) and Löve ( 1984 ) remain important reference
points, subsequent literature revealed them insuffi cient or incongruent in the face of
new fi ndings, and novel interpretations for some controversial biosystematics ques-
tions concerning perennial Triticeae species have been recently proposed (see, e.g.,
Mahelka et al. 2013 ; Wang and Lu 2014 ; Wang et al. 2015 ). As a matter of fact, it is
quite obvious that, as more and robust information becomes available, taxonomic
treatments change to refl ect this information; however, extent and timing of their
acceptance and adoption remain subjective. As a consequence, often multiple taxo-
nomic treatments are in use at any given time (Barkworth and von Bothmer 2009 ).
Because taxonomic consideration are not within the scopes of this chapter, in line
with what stated by Yen et al. ( 2005 ), taxonomy will be used here as “a tool for spe-
cies recognition,” and, perhaps primarily, as “a guide for germplasm utilization, and
C. Ceoloni et al.