ABSTRACT

Five maize (Zea mays L.) genotypes were crossed in a complete diallel scheme

and the resulting progenies were assessed for yield, general and specific

combining abilities aiid reciprocal effect in the diallel analysis. The experiments

were laid out in a randomized complete block design (R.C.B.D.) with three

replications at Okeikpe, Abia State, Nigeria in 2003 and 2004. The experimental

plots consisted of three Sm rows spaced at 0.75m with a total of 50 Plants per clot.

The traits assessed included: days to 50% tasseling, length of tassel, plant height

(PH), grain yield (GY), number of leaves per plant at harvest, leaf area,

general/specific combining abilities and reciprocal effect. General combining

ability (G.C.A.) and specific combining ability (S.C.A.) were determined

including the reciprocal effect using Griffing's (1956) method 1 and mixed model

B assumption of genetic variance. There was genetic variability among hybrids

and the best hybrids were Bende White X FARZ 32 (Yellow), Bende White X

FARZ 7 (White), TZBR Ed3C2X FARZ 7 (White) and FARZ 7 (White) X FARZ

32 (Yellow) which differed significantly from their parents (P<0.i).

Subsequently, they had higher yields, longer tassels, larger leaf area and reduced

days to 50% tasseling based on specific combining ability (S.C.A.) values. he

amoiit of general combining ability (G.C.A.) relative to the total variation

indicated that additive effects predominated for gain yield, plant height, days to

50% tasseling and number of leaves per plant at harvest. Significant S.C.A.

(P<0.01) was also found for plant height, leaf area, number of leaves per plant at

harvest and grain yield indicating that some of the variations could be attributed to

genetic dominance effect. Reciprocal effects showed that reciprocal crosses were

significant (P<0.01) for grain yield and plant height but were lower for days to

50% tasseling, tassel length and number of leaves per plant at harvest.