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cultivars with the Pch1 gene, which exhibited no yield depression, such as the cul-
tivar Lynx (Worland and Snape 2001 ).
One of the most dangerous threats to world wheat production is the stem rust
( Puccinia graminis f. sp. tritici Pers.) race Ug99, which originated in Africa.
Resistance gene Sr22 is present on a chromosomal translocation derived from
Triticum boeoticum Boiss. Only a limited number of cultivars were selected due to
the poor agronomic performance of lines carrying this resistance gene. Linkage
analysis of simple sequence repeat (SSR) markers was performed on chromosome
7A to identify loci closely linked to Sr22. Resistant lines were identifi ed, having
less than 6 % of the chromosome arm derived from T. boeoticum. These lines may
provide a more agronomically desirable source of Sr22 that can be readily deployed
to develop cultivars resistant to Ug99 (Olson et al. 2010 ).
Several other genes for resistance to rust diseases have been introduced from
Aegilops and Thinopyrum species to common wheat. According to the catalogue
published by McIntosh et al. ( 2008 , 2010 ), the following leaf and yellow rust resis-
tance genes were isolated from the wild relatives of wheat: Lr9 — Ae. umbellulata ;
Lr24 and Lr29 — Thinopyrum ponticum ; Lr37 and Yr17 — Ae. ventricosa ; Lr38 — Th.
intermedium ; Lr28, Lr35, Lr36, Lr51 and Lr66 — Ae. speltoides ; Lr21 , Lr22a , Lr32 ,
Lr39 , Lr40 , Lr41 and Yr28 — Ae. tauschii ; Lr57 and Yr40 — Ae. geniculata ; Lr58 —
Ae. triuncialis ; Lr53 , Yr15 , Yr35 and Yr36 — Ae. longissima and T. dicoccoides
(Amandeep et al. 2012 ).
Distant hybridisation has been given particular attention in regions where natural
populations of wild species have great genetic variability, and where they were used
in agricultural production before the introduction of modern cultivation practices
due to their agronomically valuable, locally adapted traits, which made them popu-
lar with local farmers. The main advantages were their adaptability and disease
resistance traits, which have been utilized by breeders in order to transfer disease
resistance genes with simple inheritance into wheat. The cultivars Plainsman V,
Plainsman IV, Encore and Frontiersman, which contain genes from Aegilops ovata ,
were selected specifi cally for increased protein content and technological quality
(Sharma and Gill 1983 ). In addition to their favourable disease resistance, Triticum
dicoccoides, Triticum monococcum , etc. are also valuable sources for broadening
the genetic base of T. aestivum in terms of increased protein content and protein
quality traits. Addition lines containing the 1E chromosome from Thinopyrum elon-
gatum improved seed storage protein quality (Garg et al. 2009 ). Similar results were
obtained with Thinopyrum intermedium when Cao et al. ( 2007 ) examined substitu-
tion for chromosome 1D of wheat. The V genome of Dasypyrum villosum (L.)
Candargy (Dv), also known as Haynaldia villosa (L.) Schur, an annual wild diploid
relative of common wheat, contains genes for elevated seed protein content and also
has a positive effect on gluten strength (Shewry et al. 1987 , 1991 ). Zhang et al.
( 2014 ) suggested that the Glu-V1 and Gli-V1/Glu-V3 loci, located in the chromo-
some 1 V of Dasypyrum villosum (L.), were proved to have positive effects on grain
quality parameters, like protein content, Zeleny sedimentation value and the rheo-
logical characteristics of wheat fl our dough.
Z. Bedő and L. Láng