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Molecular Plant Breeding 2013, Vol.5, No.7, 36
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Table 1 Overall performance of 5+10 and 2+12 entries at all India level
Arameters
Overall performance
Statistical difference (P value)
Variability (%)
5+10
2+12
5+10
2+12
Bread loaf volume (cc)
564
553
<0.000
3.60
4.70
Bread quality score
7.07
6.80
<0.000
8.60
10.6
Chapati
quality score
7.53
7.55
0.229
4.27
5.20
Biscuit spread factor
6.93
6.96
0.280
8.60
11.2
1000 grain weight (g)
39.1
39.4
0.186
9.99
9.66
Grain protein content (%)
11.9
11.7
0.087
7.51
8.59
Sedimentation value (ml)
44
42
<0.000
15.6
11.8
Grain hardness index
77.0
74.0
0.001
10.5
15.2
Flour extraction rate (%)
68.8
68.8
0.405
3.12
3.71
Wet gluten content (%)
30.1
30.9
0.007
9.92
11.4
Dry gluten content (%)
10.1
10.2
0.116
9.94
10.6
Gluten index (%)
62
57
<0.000
17.1
14.7
GLU 1 score
6~10
4~8
<0.000
12.0
11.4
Note: Overall performance represents mean during 2003-2014 and variability denotes coefficient of variability in study material
of sedimentation volume ≥60 could only be noted
5+10 wheats. This group also had an edge in gluten
index as entries of very low gluten index (≤40%) were
noted only in 2+12 wheats.
1.2 Variations in grain properties
Besides mean performance, coefficient of variation
also varied among 5+10 and 2+12 wheats and
differences in variance were confirmed by F test.
Phenotypic variability in 2+12 wheats was statistically
higher in end-products quality, protein and gluten
contents, grain hardness and flour recovery. Variability
for sedimentation volume, gluten index and GLU 1
score was found better in 5+10 wheats. Under the
light of such observations, it is anticipated that global
warming might bring more variations in traits like
protein/ gluten contents, grain hardness and flour
recovery but in dough quality related parameters like
sedimentation volume and gluten index, variability
might squeeze.
1.3 Alterations in grain quality relationships
It was interesting to note that with no disparity in
grain weight, protein and dry gluten; wet gluten levels
in 2+12 wheats were significantly better than 5+10.
High wet gluten content in 2+12 group can be
attributed to better water absorption capacity of such
wheats. To investigate this peculiar behaviour, gluten
levels were plotted against protein content (Figure 2).
There was no peculiar difference in the dry gluten
content but pattern changed in wet gluten. There was
linear response in 2+12 wheats as wet gluten content
continued to increase with enhanced grain protein.
However, no increase in wet gluten content was
visible in the 5+10 wheats once protein content
exceeded 13% level. It means that very high protein
levels in 5+10 wheats are no guarantee of enhanced
wet gluten levels.
Figure 2 Trend in protein-gluten and protein-bread quality
relationship
Study points that variations in wet gluten derived from
per unit protein exist in wheat. Significant genotypic
differences in wet gluten-protein ratio had been
reported by Zimic et al. (2006). In this investigation,
mean wet gluten protein ratio of 2.54 in 5+10 wheats
was significantly lower than 2.64 observed in 2+12
(
P≤0.001
). Besides mean difference, the pattern of
association was also different in these two categories
of wheat (Figure 3). In 5+10, wet gluten per unit
protein increased when protein varied from 8-11%,
remain static at 2.5 in the genotypes of protein range
11%~12% but decreased sharply when protein
exceeded 12%. R
2
value of this polynomial order 2
trend was 0.12. Such pattern was not strong in 2+12
group as R
2
reduced from 0.12 to 0.03.