Combining Ability and Gene Action in Single Crosses of ‎Maize (Zea mays L.) Using (Line×Tester) Method

Reem Saleem Ali*(1)   Samir AL-Ahmad(2)   Bolous Khoury(3)

(1). Agricultural Research Center of Lattakia, GCSAR, Damascus, Syria.

(2). Agricultural Research Center of Tartous, GCSAR, Damascus, Syria.

(3). Field Crops department, Faculty of Agriculture, Tishreen University, Lattakia, Syria.

(* Corresponding author: Eng. Reem Ali. E-Mail:

Received: 11/03/2019                               Accepted: 01/06/2019


The present research was conducted at Lattakia Research Center, General Commission for Scientific Agricultural Research, Syria, to study combining ability and gene action of ear length (cm), number of rows per ear, number of kernels per row, and grain yield (ton/ha). Thirty crosses produced using Line × Tester method (10 × 3) in 2016 season which were evaluated during 2017 season. The experiment was conducted using randomized complete block design (RCBD) with three replications. Results indicated that non-additive gene action was more important than additive gene action in controlling all traits. The ratios σ2GCA2SCA was less than one for all traits. General Combining Ability (GCA) effects showed that the lines (IL.291), (IL.358), and (IL.322) had good general combiners for grain yield. Specific Combining Ability (SCA) effects showed that the crosses (IL.21×IL.155), (IL.21×IL.1), (IL.121×IL.200), (IL.121×IL.322), (IL.121×IL.291) and (IL.197×IL.98) were the best F1 cross combination for grain yield. The Lines showed the highest contribution ratios in variation of grain yield (77.9%), ear length (42.8%) and number of rows per ear (61.8%), while the crosses showed the highest contribution ratios for number of kernels per row (65.9%).

Key words: Maize, Grain yield, Combining ability, Line × tester.

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Genetic Analysis of Some Productivity Traits and Earliness in Upland Cotton (Gossypium hirsutum L.)

Rawaa El-Shiekh Attiea*(1)

(1). General Commission for Scientific Agricultural Research (GCSAR), Damascus, Syria.

(*Corresponding author: Dr. Rawaa El-Shiekh Attiea. E-Mail: dr.

Received: 12/11/2019                                Accepted: 31/12/2019


Genetic potential, combining ability, heterosis effects and heritability were studied in F1 genotypes of Gossypium hirsutum L., at Cotton Research Station in Deir Ezzor, Syria. Four parental genotypes (Aleppo 33/1 (P1), Deir Ezzor 22 (P2), Line 106 (P3) and Line G73 (P4)) and their six F1 half diallel progenies were grown in a randomized complete block design with three replications in 2011 season to study seed cotton yield (; lint percentage (L.P.%) and earliness percentage (E.P.%). Results showed significant (p≤0.01) differences among the genotypes, parents and crosses for seed cotton yield and lint percentage. Significant (p≤0.05) differences were observed for parent vs. crosses indication to average heterosis over all hybrids for the above two traits. For earliness, insignificant differences were showed among genotypes, crosses and parent vs. crosses, but significant (p≤0.05) differences were showed among parents. Results indicated that best genotypes which performed highest mean and general combining ability were: lines 106 and G73 for seed cotton yield; Deir Ezzor 22 for lint percentage and Aleppo 33-1 for earliness percentage. Thus, it could be suggested that these parental varieties could be utilized in a breeding program for improving these traits to pass favorable genes for improving hybrid and subsequently producing improved genotypes through the selection in segregating generations. Best crosses based on mean performance and/or heterosis and/or specific combining ability were Aleppo 33-1*G73 followed by Aleppo 33-1*line 106 for seed cotton yield; Aleppo 33-1*G73 for lint percentage and Line 106*G73 for earliness percentage. Suggesting that these crosses could be used in breeding program to improve such traits. On the other hand, results showed high value of H2b % and low value of H2n%for seed cotton yield,  ascertained that dominance effects had great role in the existence of the variability of this trait, which insure that the expected gain from recurrent back crossing for seed cotton yield would be high in the breeding program. However, estimates of H2b % and H2n% for both of lint percentage and earliness percentage were high. Theses convergence of narrow and broad heritability values revealed that both additive and non-additive gene actions played important roles in the inheritance of these two above traits, so breeding program should contain selection and hybridization for improving these traits.

Kay words: Cotton, Combining ability, Heterosis, Heritability.

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Estimation of Heterosis and Combining Ability For the yield Components in Single Crosses of Corn (Zea mays L.)

Haitham A. Sattar Saeid*(1) Azeez H. Majeed(1) and Aziz S. Shallal(1)

(1). Breeding and development Plant Center, Agricultural Directorate, Ministry of Science and Technology, Iraq.

(*Corresponding author: Haitham A. Sattar Saied. E-Mail:

Received: 19/09/2019                                Accepted: 20/11/2019


The study used half diallel cross among six inbred lines of maize namely (1) DP198, (2) WA245, (3) HK258, (4) SA266, (5) AH401 and (6) IK58 were used. The seeds of inbred lines and its single cross hybrids were grown in an experiment using randomized completely block design (RCBD) with three replicates at a field of Research Center of Plant Breeding Improvement (AL-Latefea Station(, during fall season of 2017 to evaluate the hybrids and to estimate heterosis and their general and specific combining ability. The studied characters were; days number to silking and tasseling 75%, plant height, ear diameter and length, number of rows per ear, number of grains per ear, 300 – kernel weight, yield per plant and protein and oil percentages. Some hybrids showed significant heterosis for most studied traits, for the single cross (1× 5) it reached (3.3) for days number of tasseling, and (127.7) for yield per plant. The squares mean of general and specific combining abilities at 0.01 level were highly significant for all traits except protein percentage, which did not appear a significance for general combining ability. Parents differed in their general combining ability effects, the results showed that the parent (6) had positive significant effects for most of the studied traits. So, the two lines (1 and 5) could be used in single hybrid production with desired traits, thereby using hybrid breeding.

Key words: Diallel cross, Single crosses, Heterosis, Combining ability.

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Combining Ability Estimation of Earliness Traits and Yield Components in Some Barley (Hordeum vulgare L.) Genotypes

Saleh Saleh(1) Mohammed Shafik Hakim(1) Abdullah Al-Yousef*(2) and Ahmed Shams ElDien Shaaban(3)

(1). Department of Field Crops, Faculty of Agricultural Engineering, University of Aleppo, Aleppo, Syria.

(2). Aleppo Agricultural Research Center, General Community for Scientific Agricultural Research (GCSAR), Damascus, Syria.

(3). Department of Biotechnology Engineering, Faculty of Technical Engineering, University of Aleppo, Aleppo, Syria.

(* Corresponding author: Dr. Addullah Al-Youssef. E-Mail:

Received: 19/03/2018                                Accepted: 19/04/2018


The research was conducted at Al_Sfireh location in Aleppo during 2015/2016 and 2016/207 seasons to estimate general combining ability GCA and specific combining ability SCA for seven genotypes of barley. Three of them were local: Arabi Aswad (P1), Arabi Abyad (P2) and Furat 3 (P3), and four entries were: Alanda-01 (P4), Rihan-03 (P5), Arizona (P6) and Avit (P7). Half-Diallel cross system were preformed between parents at first season. In the second season, parents and hybrids were planted to study days to heading (DTH), days to maturity (DTM), fertile tillering number per plant (FT), grain number per main spike (GN) and thousand kernel weight (TKW). The parents p1 and p3 showed a high general combining ability for the most studied traits.  The hybrid (P1×P3) had significant value for SCA effects in most studied traits. The hybrids: (P4×P6, P5×P7, P4×P5) had significant value for SCA effects for (GN). Variance component of GCA and SCA were highly significant, and this indicates to the importance of additive and non-additive gene action in inheritance of the studied traits. The ratio of GCA/SCA was less than 1.0 for DTH, DTM and TKW and this indicates to importance of dominant and over dominant genes in inheritance of these traits. Whereas the ratio was bigger than 1.0 for FT and GN and this indicates to importance of accumulated genes in inheritance of these traits

Key Words: Half-Diallel cross, Combining ability, Earliness, Yield, Barley.

Full Paper in Arabic: PDF