الفهرس 
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Abstract
Eight lines of yellow inbred maize lines were used in experiment of a half diallel cross during 2015 and 2016 summer seasons at the research farm of the Egyptian Agricultural Company for Seed production (EGAS) in Beniheder- Benisuef governorate to produce 28 yellow maize hybrids. The experiment carried out in Randomized Complete Block Design (RCBD) with four replications. The data were collected for studying ten different traits days to 50% pollen, days to 50% silking, plant height, ear height, ear length, ear diameter, number of rows/ear, number of kernels/rows, 100 kernel weight and grain yield using Griffing method 2 model 1 to calculate general and specific combining ability, heterosis and heritability and evaluate the hybrids to choose the best lines.
Mean performance of combined 2016-2017 data showed that the best line for yield is 1858 and the hybrid (298x711).
In summer season 2016, The results showed that there is no significance for general combining ability for all studying traits except ear diameter and ear length were significant, For specific combining ability results showed that all traits were highly significant except 100 kernel weight was not significant. In summer season 2017, the results showed that there is no significance for general combining ability for all studying traits except ear diameter and grain yield were significant, but for specific combining ability the results showed that all traits were highly significant.
General combining ability for line 711 (yield trait) was significant that mean this line has high ability to combined with other lines in general. High positive general combining ability was useful in increasing yield and effected by ear length, ear diameter, number of rows/ear, number of kernels/rows and 100 kernels weight. But for days to 50% pollen and silking , plant height and ear height the negative values are important in breeding programs because it led to earliness and decrease lodging and broken plant percentage in the field which led to increase grain yield .
Specific combining ability (combined 2016 and 2017) for cross 711x1005 was significant values in most of studied traits. The results of SCA showed that cross 711x1005 has high specific combining ability for ear height and ear diameter traits.
Heterosis was calculated over mid and better parents was highly negative heterotic effect for both mid parent and better parent in days for 50% pollen and silking traits.
For the other traits it recorded high positive values over both mid parent and better parents such as plant height, ear height, ear length, ear diameter, number of rows / ear, 100 kernel weight, number of kernels / row and grain yield which proved that the hybrids were more powerful and earlier than their parents. Heterosis of (726x1858) was significant in most of studied traits indicating that is the best hybrid.
Heritability was calculated for narrow sense and broad sense, which broad sense heritability was higher than narrow sense heritability for all studied traits. The combined of the two seasons 2016 and 2017 heritabilites values it can indicate to know which trait can be useful for selection, ear diameter, ear length have high value of heritability broad and narrow sense this indicate to these trait is heritable good and if mass selection is applied it will result in permanent change of trait under artificial selection.
Electrophoresis were done for lines 472, 711, 726, 1005 and 1858 by using SCoT technique with 6 primers (SCoT 4, SCoT 5, SCoT 7, SCoT 9, SCoT 12 and SCoT 14) for PCR to perform a fingerprint to be indicated for the same selected lines and some hybrids. SCoT 7, SCoT 9 has 5 unique bands, SCoT 12 has 3 unique bands and SCoT 4 has 1 unique band which can be used as a fingerprint for the selected lines.