Data on combining ability are important for determining crossing pairs when obtaining hybrid genotypes. Total combining ability (GCP) shows how effectively parental lines transmit their traits to offspring on average across all combinations. Specific combining ability (SCA) evaluates the efficiency of specific pairs of crosses. Higher SCA values indicate dominant gene effects, whereas high GCA values indicate a significant role of additive gene effects, which is consistent with the literature.
In this study, 5 maternal lines and 4 parental lines (testers) were used to obtain 16 hybrid combinations for the purpose of GCA and SCA analysis for the main selection traits, using diallel analysis by the Griffing method.
The results. During the analysis of the GCA variant, a high reliable difference indicates the differentiation of the parental forms of the hybrids in terms of combining ability. It has been established that in the genetic determination of traits, a significant role belongs to genes of additive action, as well as to non-additive effects of genes. The evaluation of the combining ability of the selection lines in the tester crossings made it possible to identify four parental forms with the largest GCA: maternal – Ivol, SD 96-16, parental – Fen, Toma-18. Four hybrid combinations: F1 (♀ RD 96 2-95 х ♂ Fen), F1 (♀ BD 96-18 х ♂ Fen), F1 (♀ Ivol D 96 х ♂ Toma-18) and F1 (♀ Mag-62 х ♂ Toma-18) showed high SCA.
The results of the study indicate the need for two-step selection – to carry out selection and hybridization between parental forms with high and medium effects of GCA and to carry out further selection work with F1 hybrid combinations with high SCA. The information obtained in this study was used for heterosis selection of cucumber.
