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Molecular Plant Breeding 2013, Vol.4, No.6, 44
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45
Results and Discussion
Exploitation of heterosis or hybrid vigour is an
important method of crop improvement adopted in
many of the crops especially in cross pollinated crops.
This phenomenon of heterosis was attracted the
attention of plant breeders due to its conspicuous
effect on economic characters especially grain yield
and also maturity, quality traits. This heterosis has
been successfully exploited in many cross pollinated
crops among which maize is the major one.
Maturity is an important attribute of a given genotype,
which directly or indirectly affects economic yield.
Maturity itself is expressed by several components
such as days to 50 per cent tasseling, days to maturity
etc. For maturity characters like days to 50% tasseling,
fourty two and eighteen crosses and days to 50%
maturity thirty five and twenty nine crosses showed
significant heterosis over better parent and standard
heterosis exhibited significant heterosis in desirable
direction (Table 1), for days to 50%tasseling heterosis
ranged from
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7.94 to 3.23 % over better parent and
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7.94 to 3.17% over standard check, for days to
50 % maturity is ranged from
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6.32 to 5.38% over
better parent
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4.30 to 5.38% standard Heterosis. Of
these, 5×2, 12×2 , 5×4 for days to 50% tasseling and
14×4, 6×5, 11×10 for 50 % maturity were may be
the desirable crosses showed significant heterosis over
mid parent and standard check (NK 6240). And totally
thirteen crosses showed significant heterosis for
both 50% tasseling and 50% maturity, among them
13×6, 7×6, 9×6 and 13×7 recorded the highest signi-
ficant heterosis for earliness. This is in confirmation
with the reports of Kalsy and Sharma (1970) and
Murthy et al
(1981), For yield characters, twenty
seven crosses and five crosses exhibited significant
heterosis over better parent and standard check,
respectively. Those crosses, which exhibited signify-
cant heterosis, it is suggested that these hybrids will
serve as useful genetic material for development of
early parents by selection in advanced generations.
Hundred grain weight is one of the important grain
characters. Grains, the ultimate economic product
from the maize plant are the net result of various
components. The total yield in maize is influenced by
several grain component characters. Ultimate grain
yield of a plant depends mainly on 100 grain weight
through various other component characters. The
study of hundred
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grain weight deserves much often
attention because grain yield is product of action and
interaction of various grain components and is
expressed through changes in its components. So,
improvement in these individual component
characters will be quite easier and its study will help
in understanding the complex metric trait, grain yield.
For the character test weight, and teterosis ranges
from –19.12 to 35.31% for better parent and from
–18.11 to 16.91% for standard check. Among these
crosses, 9×4, 13×2 and 4×3 were top three desirable
crosses showed the significant heterosis in positive
direction over better parent as well as standard check.
Grain yield per plant is the important yield characters.
Grain yield is a complex quantitative character which
is influenced by other ancillary and component
characters. Hence all changes in the components
would not be expressed as changes in yield but all
changes in yield would be accompanied by changes in
one or more components. For the character, grain
yield per plant seventy six and five crosses showed the
significant heterosis over better parent and standard
check, respectively. The magnitude of heterosis
ranged from
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4.48 to 87.29% better parent and –31.58
to 22.11 % for standard check. The crosses, 9×5, 10×7,
4×3, 8×7 and 14×10 were found to be desirable
crosses and these also recorded significant heterosis
over better parent as well as over standard check. The
present work is in agreement with previous findings of
Nagesh Kumar et al (1999), Devi and Prodhan (2004)
and Unay et al (2004). Starch and protein are two
important constituents of grain yield and these are
very complex characters, which are influenced by
other important characters, mainly yield and its
attributes. So, comprehensive study becomes very
different.
For quality parameters like for protein content, forty
and twenty two crosses and for starch content fourty
six and nineteen showed significant Heterosis in
favourable direction, heterosis ranged from
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36.62 to
32.39% for better parent and
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40.41 to 27.69% over
standard check for protein content and for starch
content Heterosis ranged from
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5.09 to 9.73 % and