Thesis presented by

Mohamed Zakaria Mohamed EL-Diasty

Under supervision of

Prof. Dr/ Ashraf Hussein Ali Abd El-Hady

Professor and Head of the department of Genetics

Faculty of Agriculture

Mansoura University

Prof Dr/

Ali Maher Mohamed El-Adl

Professor of Genetics

Faculty of Agriculture

Mansoura University

**Introduction**

**Aim of the work**

**Material and Methods**

**Conclusion**

Corn is one of the most important source of carbohydrates for feeding both human and animals. In Egypt, as well as all other countries, corn is considered an important field crop where it is cultivated for an area over 1.80 million feddans to meet the demands of feeding human and animals

In this study, two mating designs were executed, one of them was the partial diallel crosses and the second was the line X tester mating design. In order to obtain dependable results, the two mating designs used the same inbred lines to achieve the equality of the genetic materials. The validity and accuracy of either mating design would be determined using the homogeneity test of variances which would indicate which mating design is suitable for estimating the desired genetic variance component.

Scientists in all countries gave corn breeding great concern and established programs to produce hybrids with high yielding ability. The research work to produce superior hybrids continued since the discovery of the phenomena of heterosis up till now.

**Results**

Corn breeders utilized different mating designs in order to obtain estimates and to determine the magnitudes of different genetic parameters. The knowledge of the magnitudes of additive and non-additive genetic variances is the important factor that dictates the breeding method which would be followed.

Since all mating designs gave estimates for the different genetic variance components, the question rises about which mating design would be more accurate and present valid estimates to those compnents

Prof. Dr.

Ashraf Hussein Ali Abd El-Hady

Prof. and Head of the Department of Genetics,

Faculty of Agriculture,

Mansoura University

Prof. Dr.

Kawther Saad Kash

Prof. of Genetics,

Faculty of Agriculture,

Mansoura University

Prof. Dr.

Ali Maher Mohamed El-Adl

Prof. of Genetics,

Faculty of Agriculture,

Mansoura University.

Examining committee

**blood**

Prof Dr/

Kawther Saad Kash

Professor of Genetics

Faculty of Agriculture

Mansoura University

Prof Dr/

Khalefa Abd El-Maksoud Zaied

Prof. Dr.

Mohamed Abd El-Baeth El-Sehy

Prof. of Genetics,

Faculty of Agriculture,

Alexandria University

The hybrids which were obtained from both mating designs were evaluated at two locations, Mansoura and Sohag.

**This study aimed to perform a comparison between two known designs i.e. partial diallel and line x tester to evaluate them through estimating GCA and SCA. The results of these two mating designs would indicate which mating design is more accurate in estimating these parameters through executing a homogeneity test of variance**

The combined analysis of variance obtained for the common two vegetative traits at Mansoura and Sohag.

The combined analysis of variance obtained for yield component traits at Mansoura and Sohag

The combined analysis of variance over both locations for vegetative traits obtained from the lines x testers mating design

The combined analysis of variance over both locations for yield component traits obtained from the line x tester mating design

Experiment

Genetic materials

2009

2008

Cultivation of the seven parental inbred lines and the three testers and hybridization of them by the two studied mating designs

Evaluation of all genotypes (parental lines, testers and the hybrids) at the two locations

Mansoura

Sohag

Studied traits

Vegetative traits

Plant height (only in Mansoura)

Ear height (in both locations)

Number of ears per plant (only in Mansoura)

Number of leaves per plant (in both locations)

Leaf area (only in Sohag)

Yield component traits

Ear weight

Number of rows/ear

Number of kernels/row

Weight of 100 kernels

Statistical analysis

In this study, several types of analysis of variance were made. The Statistical procedures used in this study were done according to the analysis of variance for Randomized Complete Blocks Design (RCBD) outlined by Cochran and Cox (1957) for both experiments to study the variation and to detect the presence of differences between genotypes. Also, to study heterosis in general.

Genetic materials

Determination of heterosis

Variance components

Genetic parameters

GCA

SCA

**Heritability**

Broad sense

Narrow sense

**Homogeneity test**

**RAPD - PCR**

Professor of Genetics

Faculty of Agriculture

Mansoura University

From the results of this study, we could conclude the following

Heterosis is of a common occurance in all corn hybrids

Diallel crosses and lines X testers are effecient in estimating GCA and SCA

GCA would be estimated with more validity and accurity from line x tester mating design

SCA would be more valid and accurate when estimated from partial diallel mating design

The choice of parents is of a great importance in producing high yielding hybrids

The choice of hybrid for each location is important due to genotype by environmental interaction

Choice of parents in hybrids production is of paramount importance in which closely related lines yield hybrids with less performance when compared with unrelated lines

Most yield traits appeared to be highly correlated with each other indicating that selection at one trait would also improve the other one

The estimates of general heterosis for vegetative traits from the mid parents (MP %), ranges, better parent (BP %) and the means of all F1 along with their ranges at both locations and from the combined data over both locations form the partial diallel crosses mating design.

The estimates of general heterosis for yield component traits from the mid parents (MP %), ranges, better parent (BP %) and the means of all F1 along with their ranges at both locations and from the combined data over both locations form the partial diallel crosses mating design

The estimates of general heterosis for vegetative traits from the mid parents (MP %), ranges, better parent (BP %) and the means of all F1 along with their ranges at both locations and from the combined data over both locations form line x tester crosses mating design

The mean performance of the seven parents and their 21 F1 hybrids resulted from the partial diallel crosses at both locations and from the combined data for vegetative traits.

The mean performance of the seven parents and their 21 F1 hybrids resulted from the partial diallel crosses at both locations and from the combined data for yield component traits.

The mean performance of the seven parents and their 21 F1 hybrids resulted from the line x tester crosses at both locations and from the combined data for vegetative traits.

The mean performance of the seven lines, three testers and their 21 F1 hybrids resulted from line x tester mating design at both locations and from the combined data for yield component traits.

The estimates of general heterosis for yield component traits from the mid parents (MP %), ranges, better parent (BP %) and the means of all F1 along with their ranges at both locations and from the combined data over both locations line x tester crosses mating design

The combined analyses of variance and mean squares of vegetative traits at both locations for all 21 F1hybrids resulted from the diallel crosses mating design.

The combined analyses of variance and mean squares of yield component traits at both locations for all 21 F1 hybrids resulted from the diallel crosses mating design.

The analysis of variance and mean squares of vegetative traits at both locations for all 21 F1 hybrids resulted from line x tester crosses.

The analysis of variance and mean squares of yield component traits at both locations for all 21 F1 hybrids resulted from line x tester crosses.

The GCA effects of all parents involved in the diallel crosses for vegetative traits at both locations.

The SCA effects of all 21 F1 hybrids resulted from the diallel crosses for vegetative traits at both locations.

The GCA effects of all parents involved in the diallel crosses for yield component traits at both locations.

The SCA effects of all 21 F1 hybrids resulted from the diallel crosses for yield component traits at both locations.

The GCA effects of the seven parental inbred lines involved in the line x tester crosses for vegetative traits at both locations.

The GCA effects of the three testers involved in the line x tester crosses for vegetative traits at both locations.

The SCA effects of all 21 F1 hybrids resulted from the line x tester crosses for vegetative traits at both locations.

The GCA effects of the seven parental inbred lines involved in the line x tester crosses for yield component traits at both locations.

The GCA effects of the three testers involved in the line x tester crosses for yield component traits at both locations.

The SCA effects of all 21 F1 hybrids resulted from the line x tester crosses for yield component traits at both locations.

The estimated amounts of heritability in broad and narrow senses at both locations obtained for vegetative and yield component traits from the diallel crosses.

The estimated amounts of heritability in broad and narrow senses at both locations obtained for vegetative and yield component traits from the line x tester crosses.

Test of homogeneity of variances between the diallel crosses and line x tester for vegetative traits at both locations and from the combined data over both locations.

Test of homogeneity of variances between the diallel crosses and line x tester crosses for vegetative traits at both locations and from the combined data over both locations.

The genotypic and phenotypic correlation between each pair for yield component traits obtained from data at Mansoura.

OP-A02 primer.

OP- B07 primer

OP- C04 primer

OP- D13 primer

OP- D13 primer

Phylogenetic analysis of the seven different maize inbred lines

The origin and pedigree of the seven parental inbred lines and the three testers of maize.

Thank You