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derivatives still bred in several world Countries endangered by Ug99 (e.g., DRRW
2011 ), and the Sweden cultivar Sunnan (Mclntosh et al. 1995 ). In India, the second
largest wheat producer in the world after China, with about 12 % share in total
world wheat production, cultivars with Lr19 + Sr25 have become popular, and
besides the rust protection, this alien transfer seems to be associated with slow leaf
senescence and increased yield (Sivasamy et al. 2010 ).
As to the Yp gene(s), also associated with Lr19 and S r25 , as it is one of its most
likely candidates, i.e., Psy1 (coding for phytoene synthase, required for endosperm
carotenoid accumulation, see Gallagher et al. 2004 ; Pozniak et al. 2007 ), the current
perception by breeders and consumers seems to be changing as compared to the
past. In fact, higher carotenoid content in the wheat grain is becoming a desirable
trait for the multiple benefi cial health effects determined by these compounds,
Fig. 11.2 Somatic chromosomes of wheat translocation and ph1 -induced recombinant lines, car-
rying different segments of Thinopyrum ponticum chromosome 7Ag, subjected to fl uorescence
GISH, as described in Forte et al. ( 2014 ). Total DNAs of wheat and Th. ponticum were labelled
with different fl uorochromes in separate experiments; as a result, Th. ponticum DNA is marked by
green fl uorescence in a and d , and by red fl uorescence in b and c. In all plates , the wheat- Th. pon-
ticum chromosomes are arrowed. ( a ) Partial metaphase plate of the bread wheat T4 translocation
line, carrying a pair of 7D chromosomes with 70 % of 7AgL on their long arms; ( b ) Complete
metaphase plate of a primary durum wheat recombinant, hemizygous for a 7A chromosome with
7Ag chromatin encompassing the entire long arm and about half of the short arm; ( c – d ) partial
metaphase plates of secondary 7A-7Ag durum wheat recombinants, with shortened amounts of
7Ag chromatin compared to the primary recombinant type: R5-2-10, with 23 % 7AgL on distal
7AL ( c ), and R23-1, with 40 % 7AgL on its 7AL arms ( d )
C. Ceoloni et al.