An Overview of Omics for Wheat Grain Quality Improvement - Crop Improvement: New Approaches and Modern Techniques - page 328

Genetic Resources for Quality Improvement
The tribe Triticeae had almost 350 species, of which wheat and barley are the mem-
bers. This natural diversity in the Triticeae gene pool can be incorporated in con-
trolled and well directed manner for which the priority is given to annual and peren-
nial Triticeae species. The species resources are distributed within gene pools and
wheat improvement for environmental stresses can be realized by genetic transfer
from these gene pools over short- and long term time frames. The allelic diversity
within Triticeae is crucial to harness for meeting the projected global demand of
wheat. The key resources of variability at priority are the primary gene pool diploid
D genome donor accessions of wheat; Aegilops tauschii , and some sources from
the tertiary gene pool possessing high potential values. Utilization of these genetic
resources to develop genetically compatible germplasm readily available for wheat
improvement needs integrated breeding approach with association of emerging
technologies and multidisciplinary specialties facilitating exploitation of molecular
tools of MAS, SMART (Selectison with marker and advanced reproductive tech-
nologies) breeding and QTLs hopefully to add to breeding efficiency.
The genes coding for high molecular weight glutenins has been dissected from
several species of Triticeae including Hordeum, Secale, Taeniatherum, Thinopy-
rum , Aegilops, Crithopsis, Dasypyrum and their different ploidy members (Wan
et al. 2002 ; Yan et al. 2002 ; De Bustos and Jouve 2003 ; Liu et al. 2003 ; Sun et al.
2004 ; Wang et al. 2006 ; Cao et al. 2007 ; Liu et al. 2007 ). Due to wheat domestica-
tion syndrome, Glu-Ay always remains silent in durum and bread wheat however
several A-genone wild species and wild tetraplopid species ( T. dicoccoides and
T. dicoccon ) express this gene (Waines and Payne 1987 ). The presence of active
Ay genes had significant positive effect on the bread-making quality (Ciaffi et al.
1995 ). The narrow allelic diversity for Glu-A1 locus in bread and durum wheat
which encodes limited number of x-type subunits and does not express an active
y-type subunit require attention to expand it by using novel allelic variants reported
by several workers in T. urartu and T. monococcum (Waines and Payne 1987 ; Ciaffi
et al. 1998 ; Alvarez et al. 2009 ; Caballero et al. 2008 ; Gutierrez et al. 2011 ). There
are extensive studies on identification and characterization of allelic variation for
Glu-D t 1 loci from Ae. tauschii and D-genome synthetic hexaploids (An et al. 2009 ;
Yan et al. 2003; Gianibelli et al. 2001; Rehman et al. 2008 ; Xu et al. 2010; Bibi
et al. 2012 ; Rasheed et al. 2012). A higher variability of HMW-GS due to their elec-
trophoretic mobility has been observed in A-genome species ( T. monococcum and
T. urartu ) Lee et al. 1999 b; Caballero et al. 2008; Gutierrez et al. 2011), AB genome
species ( T. dicoccoides ) (Ciaffi et al. 1993 ), and D-genome species ( T . tauschii )
(Rehman et al. 2008 ). More recently, Niu et al. ( 2011 ) analyzed HMW-GS in Th.
bessarabicum, Th. intermedium, Lophopyrum elongatum , Ae. markgrafii and their
addition lines. The information provided is useful for the development of molecular
markers that will facilitate the introgression of desirable genes from the alien chro-
mosomes into wheat genomes. The identified novel HMWGS alleles may serve as
new genetic resources for wheat quality improvement.