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reported by Qi et al. ( 2011 ) with Dasypyrum villosum (  Sr52 ). A new dimension to
the wild progenitor usage also exists in land race genetic diversity resources that
are worthy of exploiting as done recently by Pretorius et al. ( 2012 ) for the South
African land races where Sr2, Sr24 and Sr34 were detected via marker diagnostics.
A Major Anticipated Contribution of the Tertiary Gene Pool using Th. bessara-
bicum
Th. bessarabicum is a diploid salt tolerant grass species with the E b genome
and a preferred alien diversity resource extensively used by wide cross research-
ers since early 1980's in England, USA and Mexico. It has been combined with T.
aestivum cv Chinese Spring to yield an amphiploid that is an octoploid (2n = 8x = 56,
AABBDDE b E b ). All seven addition lines have since been produced from the initial
five were studied by Zhang et al. 2002 . The initial addition line set was shared
with R.R-C Wang by A. Mujeeb-Kazi from CIMMYT, Mexico. Very recently the
complete set of seven was developed by Kazi 2011 . The germplasm provided to Xu
by R.R-C Wang in USA has been screened by Xu et al. 2009 for evaluating each
addition line (2n = 6x = 42 + 2 = 44; 1J {E b } to 7 {E b }) and the amphiploid for UG99
resistance. Results have shown considerable promise for resistance to race TTKSK
(known as UG99 or TTKS). Disease scores of 0, 1 and 2 were considered as low
infection types and the data obtained by Xu et al. 2009 suggests that the amphiploid,
and addition lines 1J, 2J, 6J and 7J (J = E b ) fell in the low infection category. Under-
way has been a program to introgress the value of resistance from the alien diploid
species into wheat using the Ph gene manipulation strategy exploiting the recessive
ph genetic stock developed by late ER Sears. This effort was initiated to promote
wheat alien translocations from the amphiploid source (Mujeeb-Kazi 2006a ) and
also initiated in a targeted manner from each disomic addition line of Th. bessarabi-
cum (Kazi 2011 ). Several Robertsonian and subtle homologous translocations have
been identified by C-banding and euploid progeny (2n = 6x = 42) recovered (Kazi
2011 ). Additional resources studies by Xu et al. 2009 included Th. intermedium, Th.
elongatum, Th. ponticum, Elynus recticetus, Ae. caudate and Ae. speltoides which
suggest the value of this removed tertiary gene pool for harnessing diversity of
value.
PowderyMildew
Wheat powdery mildew, caused by Blumeria graminis (DC.) E.O. Speer f. sp. Triti-
ci Em. Marchal (  Bgt ) = Erysiphe graminis DC . Ex Merat f. sp. Tritici Em. Marchal,
is one of the most devastating diseases of common wheat occurs in many areas,
including China, Germany, Japan, Russia, United Kingdom, South and West Asia,
North and East Africa, and the Southeastern United States. Yield losses range from
13-34 % due to this disease (Griffey et al. 1993 ). To date, 41 loci with more than
60 genes/alleles for resistance to powdery mildew have been identified and located
on 18 different chromosomes in bread wheat. 29 resistance genes/alleles have been
tagged with different types of molecular markers. The desirable type of resistance
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