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Cotton Genomics and Genetics
16
Table 2 Variance due to general and specific combining ability for different quantitative characters
Sl. No.
Characters
Variance due to GCA Variance due to SCA GCA/SCA
1
Plant height (cm)
11.49800
6463.54050
0.00275
2
No. of sympodia
0.01625
123.35975
0.00000
3
No. of bolls
0.91925
343.62825
0.00275
4
Mean boll Weight (g)
0.01025
1.65775
0.00675
5
Seed index (g)
0.03150
17.79225
0.00175
6
Ginning outturn (%)
0.12650
94.93500
0.00100
7
Lint index (g)
0.01050
6.56300
0.00150
8
Seed cotton yield (kg/ha)
21916.52625
1165676.92500
0.01700
Figure 1 Estimates of general combining ability effects of
parents for seed cotton yield included in Line x Tester
interspecific crosses (YHB)
1.6 Number of bolls per plant
Out of the 23 testers, 15 testers showed significant
gca
effects for number of bolls per plant. ZCH 8 (2.02),
DH 37-4 (1.62), DH 8-7 (1.85), DH 29-1 (1.33), DH
35-17 (5.29), DH 13-7 (1.49) and DH 23-21 (5.18)
exhibited significant positive
sca
effects in the
desirable direction, whereas testers DH 18-31 (-3.25),
178-24 (-3.34), DH 24-4 (-2.38), DH 11-8 (- 1.03),
DH 23-4 (-3.19), DH 75- 23 (-2.63), DH 91-1 (-2.38)
and DH 45-23 (-1.23) showed significant negative
gca
effects in desirable direction. Out of 4 lines, three
lines exhibited significant
gca
effects in desirable
direction, the lines DB 534 and DB 532 exhibited
positive significant
gca
effects 1.06 and 0.52
respectively. While the line DB 533 (-1.51) recorded
significant negative
gca
effect. Out of 92 crosses, fifty
three crosses recorded significant
sca
effects in
desirable direction. Twenty five crosses showed
positive significant
sca
effects and the cross DH 23-1
x DB 532 (8.61) exhibited higher value of positive
significant
sca
effect. Whereas, twenty eight crosses
recorded negative significant
sca
effects.
1.7 Mean boll weight (g)
The estimates of
gca
effects of tester parents in the
population based crosses were found to be significant
in twelve testers, out of which six were positive
significant and other were negative significant
differences, shown the highest values by the testers
DH 49-1 (0.34) and DH 18-31 (0.25). Among the lines,
three showed significant differences of
gca
effects and
the line DB 534 had significant positive of
gca
effect
(0.16). Ninteen crosses expressed significant
sca
effects, out of which nine recorded positive significant
sca
effects and the cross DH 31-2 × DB 533 (0.77)
had higher value of positive significant
sca
effect.
1.8 Seed index (g)
Nine tester parents exhibited significant
gca
effects,
four testers had significant
gca
in positive direction
and highest was recorded in DH 13-7 (1.18). Among
the lines, DB 534 showed positive significant
gca
effect (0.27). Thirteen crosses revealed significant
sca
effects, of these six crosses showed positive
sca
effects and the highest was displayed by the cross DH
23-21 × DB 532 (2.61).