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Studies Heterosis Exploitation Heterotic Boxes Seed Cotton Yield Attributing Characters
47
Potdukhe (2002) also reported heterosis over mid
parent. The cross DH 98-27 X (DB 533 x DB 534 F
4
IPS 49) (39.97) recorded highest significant positive
heterosis over commercial check MRC 6918 and the
cross 178-24 X (DB 533 x DB 534 F
4
IPS 33) (-44.37)
exhibited lowest significant negative heterosis over
MRC 6918. Two crosses showed significant heterosis
in positive direction and two crosses showed
significant heterosis in negative direction over MRC
6918. In case of DCH 32 non
Bt
check, the cross DH
98-27 X (DB 533 x DB 534 F
4
IPS 49) (44.31)
showed highest significant positive heterosis over this
check, but the cross 178-24 X (DB 533 x DB 534 F
4
IPS 33) (-42.65) recorded lowest significant negative
heterosis value over DCH 32 commercial check. Two
crosses exhibited significant positive heterosis over
DCH 32 commercial check and only one cross
showed significant negative heterosis.
1.2 Plant height (cm)
Plant height is one of the important character of
growth and development of the cotton canopy. There
was increase in number of sympodia per plant and
number of bolls per plant with increase in plant height.
Per cent heterosis of F
1
crosses over their respective
mid parental values ranged from 68.57 [ZCH 8 X (DB
533 x DB 534 F
4
IPS 14)] to -6.96 [DH 98-27 X (DB
533 x DB 534 F
4
IPS 14)]. Majority of the crosses
exhibited significant heterosis over mid parent in
positive direction. Significant positive revealed by 51
crosses. Significant and positive heterosis for plant
height was earlier reported by Singh and Narayanan
(1993), Bhatade and Rajeshwar (1994), Sambamurthy
et al. (1995) and Rajput et al. (1997).
The cross DH 98-27 X (DB 533 x DB 534 F
4
IPS 17)
(33.80) showed highest significant positive heterosis
over commercial check MRC 6918, the cross DH
98-27 X (DB 533 x DB 534 F
4
IPS 14) (-21.24)
exhibited lowest heterosis over MRC 6918 and only
three crosses showed significant heterosis in positive
direction. In case of DCH 32 non
Bt
check, the cross
DH 98-27 X (DB 533 x DB 534 F
4
IPS 17) (23.46)
showed highest positive heterosis over this check, but
the cross DH 98-27 X (DB 533 x DB 534 F
4
IPS 14)
(-27.33) recorded lowest significant negative heterosis
value over DCH 32 commercial check. Only one cross
had significant negative heterosis over DCH 32
commercial check.
1.3 Number of monopodia per plant
The monopodial branches utilize more energy and
delay the reproductive parts. More vegetative
branches are undesirable and any genetic parameter in
negative direction is desirable. Per cent heterosis of F
1
crosses over their respective mid parental values
ranged from 446.82 [178-24 X (DB 533 x DB 534 F
4
IPS 38)] to -41.58 [DH 98-27 X (DB 533 x DB 534 F
4
IPS 62)]. Majority of the crosses exhibited significant
heterosis over mid parent in positive direction.
Seventy two crosses showed significant positive
heterosis and three crosses revealed significant
negative heterosis over their mid parent. In many
crosses, heterosis over mid parent has been observed
as significant positive heterosis. Similar reports were
made by Reddy (2001), Neelima (2002) and Potdukhe
(2002).
The cross DH 98-27 X (DB 533 x DB 534 F
4
IPS 23)
(22.00) recorded highest positive heterosis over
Bt
check MRC 6918, the crosses DH 98-27 X (DB 533 x
DB 534 F
4
IPS 62) (-44.50) and DH 98-27 X (DB 533
x DB 534 F
4
IPS 34) (-44.50) exhibited lowest
negative significant heterosis over MRC 6918 and
twenty eight crosses showed significant negative
heterosis. In case of DCH 32 check, the cross DH
98-27 X (DB 533 x DB 534 F
4
IPS 23) (46.55)
showed highest significant positive heterosis over this
check, but the crosses DH 98-27 X (DB 533 x DB 534
F
4
IPS 62) (-33.33) and DH 98-27 X DB 533 x DB
534 F
4
IPS 34 (-33.33) recorded lowest significant
negative heterosis value over DCH 32 commercial
check. Six crosses had significant negative heterosis
and eighteen crosses exhibited significant positive
heterosis over DCH 32 commercial check.
1.4 Number of sympodia per plant
Per cent heterosis of F
1
crosses over their respective
mid parental values ranged from 52.83 [DH 18-31 X
(DB 533 x DB 534 F
4
IPS 15)] to -17.95 [DH 98-27 X
(DB 533 x DB 534 F
4
IPS 71)]. Thirteen crosses
showed significant positive heterosis over their mid
parent. Significant heterosis over mid parent for this
character was observed by Reddy (2001), Neelima
(2002) and Potdukhe (2002).
The crosses DH 98-27 X (DB 533 x DB 534 F
4
IPS 30)
(29.08) and DH 18-31 X (DB 533 x DB 534 F
4
IPS
Cotton Genomics and Genetics