Diallele crosses in 10 early maturing inbred lines of corn (Zea mays L.) were used to estimate genetic parameters for yield, some yield components as well as other traits. F1 and reciprocal crosses were evaluated in a triple lattice design , in 2002. Significant
( p< 0.01) differences were observed among genotypes for all studied traits. Therefore , Griffing’s method 3 , model 1 was used to partition the genotypic effect into general combining ability (gca) ,specific combining ability (sca), and reciprocal effects. Variances due to gca and sca, and also the reciprocal effects were significant ( p< 0.01 ) for all studied traits. According to Baker , the ratio of was calculated for each trait to detect the relative importance of additive and non additive gene effects . Based on this ratio, additive gene effects were more important than non additive gene effects for all the studied traits . General combining ability effects were significant for most parents in all the studied traits. Specific combining ability effects were significant in few crosses (for all the traits studied), except for yield and plant height, in which they were significant in more than 50 % of the crosses. High heterosis was observed in more than 50 %of the crosses for all studied characteristics. The highest and lowest degrees of heterosis were observed for grain yield and number of ear row, respectively. Number of days from planting to tassel emergence and maturity indicated negative heterosis. Although high broadsence heritability estimates (0.85 to 0.95) were observed for most traits, the estimates of narrowsence heritability were relatively low, the lowest values belonging to number of kernel row and grain yield (0.23 and 0.38) respectively. Number of days from planting to maturity was of the highest narrowsence heritability ( 0.74).
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