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Studies Heterosis Exploitation Heterotic Boxes Seed Cotton Yield Attributing Characters
49
Somashekhar (2006) and Deepakbabu (2007).
1.8 Sympodial length at 50 per cent plant height (cm)
Per cent heterosis of F
1
crosses over their respective
mid parent values ranged from 84.71 [ZCH 8 X (DB
533 x DB 534 F
4
IPS 23)] to -32.74 [DH 98-27 X (DB
533 x DB 534 F
4
IPS 30)]. Eleven crosses showed
significant positive heterosis and only two crosses
recorded significant negative heterosis over their mid
parent. Significant positive heterosis over mid parent
and commercial check was reported by Mallikarjun
(2005), Somashekar (2006).
The cross DH 98-27 X (DB 533 x DB 534 F
4
IPS 38)
(75.25) recorded highest significant positive heterosis
over commercial check MRC 6918 and the cross DH
18-31 X (DB 533 x DB 534 F4 IPS 16) (-22.08)
exhibited lowest negative heterosis over MRC 6918.
Five crosses showed significant heterosis over MRC
6918 in positive direction. In case of DCH 32 check,
the cross DH 98-27 X (DB 533 x DB 534 F
4
IPS 38)
(36.43) showed highest significant positive heterosis
over this check, but the cross DH 18-31 X (DB 533 x
DB 534 F
4
IPS 16) (-39.34) recorded lowest
significant negative heterosis value over DCH 32
commercial check.
Eleven crosses exhibited
significant negative heterosis and only two recorded
significant positive heterosis respect to this trait over
DCH 32 commercial check.
1.9 Seed index (g)
Per cent heterosis of F1s over their respective mid
parent values ranged from 80.45 [DH 98-27 X (DB
533 x DB 534 F
4
IPS 32)] to -29.96 [DH 98-27 X (DB
533 x DB 534 F
4
IPS 13)]. Twenty five crosses
showed significant positive heterosis and seven
crosses recorded significant negative heterosis over
their mid parent. Heterosis over mid parent was
reported by Reddy (2001), Neelima (2002) and
Potdukhe (2002), Karande et al. (2004) and Maisuria
et al. (2006).
The cross DH 98-27 X (DB 533 x DB 534 F
4
IPS 32)
(83.87) recorded highest significant positive heterosis
over
Bt
check MRC 6918 and the cross DH 98-27 X
(DB 533 x DB 534 F
4
IPS 13) (-26.43) exhibited
significant negative heterosis over MRC 6918.
Fourteen crosses showed significant heterosis in
positive direction and two crosses recorded significant
negative heterosis over MRC 6918. In case of DCH
32 check, the cross DH 98-27 X (DB 533 x DB 534
F4 IPS 32) (84.16) showed highest significant positive
heterosis over this check, but the cross DH 98-27 X
(DB 533 x DB 534 F
4
IPS 13) (-26.32) recorded
lowest significant negative heterosis value over DCH
32 commercial check. Fourteen crosses exhibited
significant positive heterosis and only two recorded
significant negative heterosis respect to seed index
over DCH 32 commercial check.
1.10 Ginning outturn (%)
Per cent heterosis of F1 crosses over their respective
mid parent values ranged from 11.31 [DH 18-31 X
(DB 533 x DB 534 F
4
IPS 105)] to -58.48 [ZCH 8 X
(DB 533 x DB 534 F
4
IPS 33)]. Twenty five crosses
showed significant negative heterosis over their mid
parent. Mid parental heterosis for GOT was reported
earlier by Reddy (2001), Neelima (2002), Potdukhe
(2002) and Sivaprasad (2003).The cross DH 18-31 X
(DB 533 x DB 534 F
4
IPS 105) (25.65) recorded
highest significant positive heterosis over commercial
check MRC 6918 and the cross ZCH 8 X (DB 533 x
DB 534 F
4
IPS 33) (-51.63) exhibited lowest
significant negative heterosis over MRC 6918. One
cross showed significant heterosis in negative
direction and two crosses recorded significant positive
heterosis over MRC 6918. In case of DCH 32 check,
the cross DH 18-31 X (DB 533 x DB 534 F
4
IPS 105)
(6.74) showed highest positive heterosis over this
check, but the cross ZCH 8 X (DB 533 x DB 534 F
4
IPS 33) (-58.91) recorded lowest significant negative
heterosis value over DCH 32 non
Bt
check. Sixteen
crosses exhibited significant negative heterosis over
DCH 32 commercial check.
1.11 Lint index (g)
Per cent heterosis of F
1
crosses over their respective
mid parent values ranged from 53.71 [DH 98-27 X
(DB 533 x DB 534 F
4
IPS 32)] to -44.65 [ZCH 8 X
(DB 533 x DB 534 F
4
IPS 30)]. Twenty four crosses
showed significant negative heterosis and four crosses
showed significant positive heterosis over their mid
parent. Heterosis over mid parent was reported by
Doss and Kadambavanasundaram (1997), Reddy
(2001), Neelima (2002) and Potdukhe (2002). The
cross DH 98-27 X (DB 533 x DB 534 F
4
IPS 32)
(82.61) recorded highest significant positive heterosis
over commercial check MRC 6918 and the cross ZCH
Cotton Genomics and Genetics