الفهرس 
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Abstract
Objectives:
1. Estimate general, specific combining abilities and heterosis among some maize inbred lines and their F1 single crosses.
2. Study the efficiency of some characteristics and identification methodology in maize inbred lines and their crosses.
3. High light the qualitative and quantitative diversity apparent between some maize inbred lines and their crosses.
4. Track the inheritance of some maize characteristics in the first generation.
5. Using morphological methods of assessment to furnish standard uniform and definitive information of the characteristics of the genotypes.
6. Get information which supplies a great deal of knowledge, which in turn support quality control and certification procedures.
Methoda& Results:
In the present investigation, six maize inbred lines were used. These inbred lines were: Sd.63, Sd.7, Inb.19, Inb.173, Inb.174 and Inb.170.
In 1st May 2011 growing season, the seeds of all parental inbred lines were planted in the Farm of the Agronomy Department, Faculty of Agriculture, Mansoura University. All parental inbred lines were crossed according to a half diallel crosses mating design to obtain 15 single cross. In 15 May 2012 growing season, all 21 genotypes, which included 6 parental inbred lines and 15 F1 single crosses were cultivated using the dry method (Afir).
Inbred parents and their F1 single crosses were evaluated through 2012 season to study the efficiency of some characteristics and identification methodology in maize genotypes. Also, to determine the role of general and specific combining ability and heterosis for some agronomic traits.
Results:
1- Estimates of GCA effects showed that, the parents P4 (Inb.173) and P5 (Inb.174) were found to be good general combiners for time to 50% tassel and silk emergence; for plant height were P1, P3, P4 and P5, where they showed negative and highly significant GCA effects for these traits. Significant positive GCA effects were found for most studied traits. Based on GCA estimates, it could be concluded that the best combiners were P1, P3 and P4 for number of rows/ear; for number of grains/row were P1, P2 and P5; for 100-Grain weight was P1; for grain yield/plant were P1 and P2; for shelling percentage were P2 and P6, indicating that these inbred parents are best general combiners for increasing these traits.
2- Based on SCA effects, it could be concluded that crosses i.e. P2×P5, P3×P6 showed significant or highly significant negative SCA effects for time to 50% tassel emergence, and crosses P1×P2, P1×P6, P2×P5 and P3×P4 for time to 50% silk emergence; for Plant height were P1×P3, P1×P5, P2×P3, P2×P6, P4×P5 and P4×P6, indicating that these crosses are the best combinations for improving these traits.
3- The results of anthocyanin coloration of sheath, brace roots, fresh anthers, glumes, base of glumes and coloration of sheath in the middle of plant showed differences between all inbred lines and their crosses. Also there were significant differences in quantitative characters i.e. plant height, blade width, blade length, angle between blade and stem, ear height, ear position, angle between main axis and lateral branches, number of primary lateral branches, length of main axis above lowest side branch, time to 50% tassel emergence and time to 50% silk emergence.
4- Phylogenetic relationship between and within six inbred lines of maize led to classify the inbred lines into two main groups depending on the genetic distance between each inbred line and the other. Data showed a similarity degree between inbred lines after using cluster analysis. The first main group divided into two subgroups; the first included P3 and P5 whereas, the second subgroup included P4 and P6. While, the second main group consists of P1 and P2.
5- On the other hand, Phylogenetic relationship between 15 single crosses of maize led to classify the hybrids into two major groups, A and B. The major group A divided into two subgroups, subgroup A1 which divided into two minor groups, minor group A1,1 which included P2×P4 and minor group A1,2 which included P3×P5, and subgroup A2 which included P2×P5. While, second main group B divided into two subgroups, B1 (P4×P5) and B2 which divided into two minor groups, B2,1 and B2,2. The minor group B 2,1 included two minor subgroups, B2,1,1 and B2,1,2. Minor subgroup B2,1,1 consists of two groups, the first included P4×P6 and P1×P2, while the second group included P5×P6. The second minor subgroup B2,1,2 consists also of two groups, the first included P1×P5 and P3×P5, while the second group included P3×P4. For the second minor group B2,2 it is clearly appeared that this minor group divided into two minor subgroups, B2,2,1 and B2,2,2. The first minor subgroup B2,2,1 included P1×P6 and P2×P3. While, the second minor subgroups B 2,2,2 included two groups, the first group contains P2×P6 and the second group included P1×P3 and P1×P4.
Conclusion:
Both morphological and bio-chemical identification methods were important in identifying maize genotypes. New technology (bio-chemical identification) can not replace traditional methods (morphological characteristics), the two should complete each other and constitute an effective technology system in maize identification. It could be concluded that morphological characters such as cub color, grain color and grain type and detection of variation at the DNA level using markers such as RAPDs technique were important and efficient in identifying maize genotypes.