The combining ability of new lines of cucumber for the main economically valuable traits

Abstract

Relevance.To create heterotic cucumber hybrids, it is important to have a high general and specificcombining ability of the initial material, which makes it possible to select valuable genotypes at anearly stage of selection.Material and methods.The research was carried out in 2018-2020. at the Research Institute ofVegetable, Melon Crops and Potatoes, located in the Tashkent region of Uzbekistan (SRIVMC&P).Studied 6 accessions of cucumber. As a result of diallelic crosses, 36 hybrid combinations wereobtained (p2). Hybridological analysis was carried out according to the first Griffing's method, including forward and backcrossing and the use of parental forms (p2). To determine the combining ability,conventional methodologies were used (1,15). Genetic-statistical analyzes were carried out usingthe MS Excel application package.Results.Studies have established that according to the traits "the number of days from seed germination to the opening of female flowers" and "the number of days until the technical ripeness offruits" in all studied cucumber accessions, the ratio (σ2ĝi<σ2si) is observed, where the dominant rolein the inheritance of this trait also belongs to genes with dominant and epistatic effects. The trait“number of fruits per plant” is controlled by dominant and epistatic gene effects (σ2ĝi<σ2si) in almostall cucumber accessions, and in the accession A-6 - by additive gene effects (σ2ĝi<σ2si). Thephenomenon (σ2ĝi<σ2si) was noted for the trait "average fruit weight", where the expression of thetrait is controlled by the dominant and epistatic effects of genes (σ2ĝi<σ2si) in three studied cucumber accessions (C-25/1, A-6 and A-9), and in the other three accessions, additive gene effects (σ2ĝi<σ2si) are more important in inheritance. The trait "productivity of one plant" is controlled by the dominant and epistatic effects of genes (σ2ĝi<σ2si) in the three studied cucumber accessions, and in theother three accessions (C-25/1, A-6 and A-9), genes play a special role for the expression of the traitwith additive effects. Promising hybrid combinations with the best performance for their use as a initial material for breeding have been revealed.