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Cotton Genomics and Genetics
48
71) (29.08) recorded highest positive heterosis over
commercial check MRC 6918 and the cross 178-24 X
(DB 533 x DB 534 F
4
IPS 15) (-17.95) exhibited
lowest negative heterosis over MRC 6918. There is no
significant heterosis respect to this trait over MRC
6918
Bt
commercial check between crosses. In case of
DCH 32 non
Bt
check, the crosses DH 98-27 X (DB
533 x DB 534 F
4
IPS 30) (17.07) and DH 18-31 X
(DB 533 x DB 534 F
4
IPS 71) (17.07) showed highest
positive heterosis over this check, but the cross 178-24
X (DB 533 x DB 534 F
4
IPS 15) (-25.58) recorded
lowest negative heterosis value over DCH 32
commercial check. There is no significant of heterosis
respect to this trait over DCH 32 commercial check
between crosses.
1.5 Number of bolls per plant
Per cent heterosis of F1s over their respective mid
parent values ranged from 135.61 [ZCH 8 X (DB 533
x DB 534 F
4
IPS 30)] to -5.27 [DH 18-31 X (DB 533
x DB 534 F
4
IPS 33)]. Sixty nine crosses showed
significant positive heterosis over their mid parent.
Siruguppa and Parameswarappa (1998), Reddy (2001),
Neelima (2002) and Potdukhe (2002) also revealed
the heterosis over mid parent for this trait.
The cross ZCH 8 X (DB 533 x DB 534 F
4
IPS 30)
(40.78) recorded highest significant positive heterosis
over commercial check MRC 6918 and the cross DH
18-31 X (DB 533 x DB 534 F4 IPS 33) (-26.60)
exhibited lowest negative heterosis over MRC 6918.
Only one cross showed significant heterosis over
MRC 6918 in positive direction. In case of DCH 32
check, the cross ZCH 8 X (DB 533 x DB 534 F
4
IPS
30) (59.45) showed highest significant positive
heterosis over this check, but the cross DH 18-31 X
(DB 533 x DB 534 F
4
IPS 33) (-16.86) recorded
lowest negative heterosis value over DCH 32
commercial check. Two crosses exhibited significant
positive heterosis respect to this trait over DCH 32
commercial check between crosses.
1.6 Mean boll weight (g)
In cotton, boll weight and boll number in inter specific
and intraspecific hybrids are reported as major
components of heterosis in yield (Pavasia et al.,
1999b). Per cent heterosis of F
1
crosses over their
respective mid parent values ranged from 32.28 [ZCH
8 X (DB 533 x DB 534 F
4
IPS 49)] to -34.94 [DH
98-27 X (DB 533 x DB 534 F
4
IPS 38)]. Five crosses
showed significant negative heterosis and one cross
recorded significant positive heterosis over their mid
parent.
The cross ZCH 8 X (DB 533 x DB 534 F
4
IPS 49)
(15.07) recorded highest positive heterosis over
commercial check MRC 6918 and the cross 178-24 X
(DB 533 x DB 534 F
4
IPS 33) (-35.62) exhibited
lowest significant negative heterosis over MRC 6918.
Eight crosses showed significant heterosis over MRC
6918 in negative direction. In case of DCH 32 check,
the cross ZCH 8 X (DB 533 x DB 534 F
4
IPS 49)
(27.27) showed highest positive heterosis over this
check, but the cross 178-24 X (DB 533 x DB 534 F
4
IPS 33) (-28.79) recorded lowest negative heterosis
value over DCH 32 commercial check. The crosses
exhibited non significant heterosis respect to this trait
over DCH 32 commercial non
Bt
check.
1.7 Reproductive points on sympodia
Per cent heterosis of F
1
crosses over their respective
mid parent values ranged from 59.75 [DH 18-31 X
(DB 533 x DB 534 F
4
IPS 6)] to -57.53 [DH 98-27 X
(DB 533 x DB 534 F
4
IPS 49)]. Twenty three crosses
showed significant negative heterosis and twelve
recorded significant positive heterosis over their mid
parent.
The cross 178-24 X (DB 533 x DB 534 F
4
IPS 12)
(81.30) 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) (-34.31) exhibited
lowest significant negative heterosis over MRC 6918.
Thirty six crosses showed significant heterosis over
MRC6918 in positive direction, while three crosses
recorded significant heterosis in negative direction. In
case of DCH 32 check, the cross 178-24 X (DB 533 x
DB 534 F
4
IPS 12) (51.00) showed highest significant
positive heterosis over this check, but the cross DH
98-27 X (DB 533 x DB 534 F
4
IPS 13) (-45.29)
recorded lowest significant negative heterosis value
over DCH 32 commercial check. Thirteen crosses
exhibited significant positive heterosis and nine
recorded significant negative heterosis respect to this
trait over DCH 32 commercial check. Significant
positive heterosis over mid parent and commercial
check was reported by Mallikarjun (2005),
Cotton Genomics and Genetics