A complete diallel csoss analysis among eight inbred lines anti
Pioneer 514 were evaluated in two planting dates (early and
late) for tasseling date, Silking date plant heihIt, ear height
and leal area. Data were ganetically analysed by the procedures
developed by Griffing (1956). Planiing date mean squares were
highly significant for all attributes Genctypes mean squares re
ached the significance level of probality for ail traits. Appre
ciable genotype by planting date interacUo were detectei
for all traits except eat area. Significantly positive co relaThion
codtficjnnt values between nitd-porenf values and F1 mean
values obtained for, tasseling date, plant height, ear height
and leal area.
The mean squares associated with general GCA and specific
SCA comibining abilities were highly signifie in all traits,
High rations which largely exceed the unity were obtained in all
trai’ts except plant height, indicating that the largest part of the
tَtai genetic variability associated with those traits was resait
of additive and additive by additive gene action. Significant
reciprocal SCA mean squares were obtained for, tasseling
date, ear and plant height. Significant GCA and SCA by planting
dates mean squares were lobtialined in all traits.
Bdth inbred lines Rg10 and K64 expressed the best combiners
for Silking and tasseling dates, and plant and ear heights.
While, both inbred lines G, 444 and G. 227 B seemed to be the
best Oombiners for leaf area. The crosses (1 X. 8) and (3 X 8)
had the lowest values of SCA eVents for earlIness. Insignificant
SCA effect was detected in seven crosses for plant height. Leaf
area, six crosses had signicant]y positive SCA effect.
EARLINESS, if found in corn, is t’avourable for escaping destruc
tive injuries caused by Sesamia cretica Led, Ohio simplex and
Pyrausta nubilalis Hb. Much efforts are devoted nowadays to
increase its productivity through genetiacal improvement. To car
ry out a successful breeding programme, the breeder should have
enough knowledge about the type and relative amount of genetic
variance components and their interactions by environments for
the attribute in question.
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