Significant general and specific combining abilities
(GCA and SCA) were obtained for all traits. The magnitudes
of the ratios of GCA/SCA revealed that the additive and
additive X additive types of gene action were he msot
important expressions for all traits. The magnitude of
the interaction for GCA was generally higher than for
specific one for most traits. The parental inbred lines
M.37, 1(64 nd M.44 showed significant negative (g1) for
silking and t,.asseling dates. The parental inbred lines
M.30 and RgiI expressed significant positive of (g1) for
grain yield/plant, number of rows/car arid number of kernels!
row. While, M.36 seemed to be the best combiner for grain
yield, 100—kernel weight and number of rows/ear.
The highest desirable SCA effects were in crosses:
RgII X M.36, RgII X M.25, RgII X M.30, 1(64 X M.54 and ،f64
X M.36 for grain yield and one or more of its components.
The cross t)gII X M.3 showed the highest useful heterosiS
for grain ielن followed by RgII X M.30. The five double
corsses; (PgII X 1(64) (M.36 X M.30), (RgII X 1(64) (M.54
X M.36), (PgII X K64) (M.36 XX M.25), (RgII X 1(64) (M.36
X M.24) and (RgII X M.36) (M.24 X M.30) surpassed the respec
tive check variety D.C. 202 by 32.35%, 24.90%, 23.50%,
10.97% and 3.5l%, respectively.