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. email@example.com).
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 (S.C.Y.kg/don.); 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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