تقدير الفعل و العدد الجيني لبعض صفات النمو في الذرة الصفراء

Abstract EN

University of Baghdad during spring and fall seasons 2009-2010.

Two maize inbreds; Nz25 and B73 were planted to produce single crosses hybrid,F2 ,F3 ,BC1,BC2,BC3 and BC4.The 9 genotypes were compared using RCBD with three replicates.

The hybrid vigor for the single crosses and inbreeding depression for F2, F3 ,BC1 and BC4,the variances of environment ,additive and dominance and the degree of dominance and heritability, number of genes were estimated ,no.

of leaves angle , leaf area and plant and were studied .

The experimental results showed significant differences in all characters in the study the highest hybrid vigor specially in plant height of 56.91%.

There was a decline in the characters in F2 , F3 , BC1 and BC2 so that we can not recommend to use seeds for commercial production.

The dominance genetic variance was significantly superior in all characters in this study than the additive, which indicate that the genetic variatnce is very important in influencing the studied characters.The estimations of the average of degree of domince were more than one for all the studied characters .

The broad sense heritability was high which ranged from 0.69 in silking to 0.98 for leaf angle, while there is a decline in narrow sense heritability which indicate an important dominance genetic superiority in the studied characters.

The number of genes which control tasseling initiation was 13 pairs and 14 for the silking imitation ,17 pairs for the number of leafs/plant ,5 pairs for leaf angle ,23 for leaf area ,10 for plant height and 8 for ear height which indicate that these characters should be improved by crossing followed by selection , for they are quantitative traits.