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LOCATION OF NOVEL VARIANTS OF HIGH MOLECULAR WEIGHT GLUTENIN SUBUNITS AND THEIR EFFECTS ON QUALITY TRAITS IN WHEAT (Triticum aestivum L.)

KrishiKosh

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Title LOCATION OF NOVEL VARIANTS OF HIGH MOLECULAR WEIGHT GLUTENIN SUBUNITS AND THEIR EFFECTS ON QUALITY TRAITS IN WHEAT (Triticum aestivum L.)
Ph D
 
Creator NISHA M.
 
Contributor Anju. M. Singh
 
Subject viruses, biological phenomena, diseases, planting, cucumbers, vegetables, application methods, crops, sampling, oils
 
Description T-8368
Wheat landraces are considered to provide useful sources of genetic variability
for various traits including those for quality. Since wheat is grown for ages in India, a
lot of diversity exists here especially in the areas bordering the Himalayas. Samples of
many of our landraces have been collected from India in the past and studied by
workers elsewhere and one of these landraces ‘NapHal’ which was found to posses a
rare HMW trait (double null) has been used to transfer this trait for development of a
strain suitable for biscuit and non fermented crackers, wafers etc. Novel subunits were
also identified in another Indian landrace ‘Pissi Local’. Screening of indigenous
collection of wheat at Grain Quality Laboratory of Indian Agricultural Research
Institute, India, led to identification of five novel variants on Glu-B1 and Glu-D1 loci.
Among these, two indigenous collections IC 296923 and IC 296924 which was found
to have novel subunit pairs 52 & 123 (in IC 296923) and 53 &123 (in IC 296924) were
chosen for the present study. These lines were investigated for finding out the location
of these novel subunits using three-way (top) cross and molecular markers. Further the
effects of this novel subunit on various quality traits were studied in the progenies of the
crosses involving these lines.
The test of allelism was carried out to confirm the genetic location of the
subunit pairs 52 & 123 and 53 &123 reported earlier in the lines IC 296923 and IC
296924 respectively. The studies confirmed that the allele for subunit 52 and 53 is
located at the Glu-D1 locus and that these subunits are suggested to be coded by the
Glu-D1x gene. The studies also confirm the earlier observations that subunit 123 is not
coded by any of the HMWGS loci and is most likely a component of the LMWGS. It is
therefore inferred that the subunit linked to 52 and 53 and coded by Glu-D1y gene is
missing in the lines IC 296923 and IC 296924 possessing these subunits. Thus, the line
IC 296923 is proposed to carry the subunits 1 (Glu-A1), 13+16 (Glu-B1) and 52+Null
(Glu-D1). Similarly the line IC 296924 is proposed to carry the subunits 1 (Glu-A1),
13+16 (Glu-B1) and 53+Null (Glu-D1). The results were further confirmed utilizing
molecular markers for Glu-Dx and Glu-Dy genes. The allele specific molecular marker
for Dx5 showed amplification of the DNA of the lines IC 296923 and IC 296924
indicating that the subunits 52 and 53 are variants of the subunit 5. On the other hand, no
amplification was observed when the gene and allele specific primers for the Glu-D1y
locus (Dy10& 12) were used for amplifying the DNA of the lines IC 296923 and IC
296924.Combining the genetic and molecular studies, allelic designations have been
proposed for these subunits as Glu-D1-1w for 52, Glu-D1-1 x for 53, Glu-D1-bu for 52+
Null and Glu-D1-bv for 53+Null.
Effect of these novel subunits on 14 quality traits (Protein content, Thousand
Kernel Weight, Diameter, Hardness Index, Sedimentation Volumes, Wet Gluten, Dry
Gluten, Gluten Index, Water Binding Capacity, Flour Recovery, Water Absorption,
Dough Stability, Dough Development Time and Degree of Softening) were studied by
making appropriate crosses.
The lines IC 296923 and IC 296924 have reduced sedimentation volume, gluten
index, dough stability, dough development time and higher degree of softening
compared to the wheat lines having different subunits (5+10 or 2+12). Analysis of
variance and F-test for these traits in the progeny groups with and without these novel
subunits showed that the novel subunits play a significant role in influencing these traits
by lowering them (increasing the degree of softening). In India, the released varieties of
the major wheat growing zones have medium hard to hard grain, medium sedimentation
volumes, medium to high protein and a Glu score of 7-10, thus being intermediate for
bread quality and poor for biscuit quality. Lines such as ‘NapHal’ with double null
subunits and ‘Pissi Local’ with subunit 17* and soft grain can serve as donors for
introducing better biscuit quality. The new lines IC 296923 and IC 296924 with the
novel subunit pairs 52+Null and 53+Null can also be used as donors for biscuit
 
Date 2016-10-26T10:11:34Z
2016-10-26T10:11:34Z
2010
 
Type Thesis
 
Identifier http://krishikosh.egranth.ac.in/handle/1/82018
 
Format application/pdf
 
Publisher IARI, DIVISION OF GENETICS