Analysis of the inheritance of the marker SCAR-R1A, linked to the Rpf1 red stele root rot resistance gene, in strawberry hybrid progeny

Background. Resistance to pathogens is an important breeding trait of a cultivar. Red stele root rot (Phytophthora fragariae var. fragariae Hickman) is a dangerous root disease. Revealing the patterns of resistance inheritance and identifying promising genotypes is an important stage in the development of strawberry cultivars resistant to red stele root rot. The purpose of the study was to identify patterns of inheritance for the SCAR-R1A marker, linked to the Rpf1 red stele root rot resistance gene, in the strawberry hybrid combinations.
Materials and methods. The target materials were the strawberry cultivars ‘Bylinnaya’, ‘Olimpiyskaya Nadezhda’, ‘Privlekatelnaya’ and ‘Feyyerverk’, and hybrid seedlings of the cross combinations Bylinnaya × Olimpiyskaya Nadezhda, Bylinnaya × Feyyerverk, Olimpiyskaya Nadezhda × Bylinnaya, Privlekatelnaya × Bylinnaya, and Feyyerverk × Bylinnaya. The Rpf1 gene was identified with the marker SCAR-R1A.
Results and conclusion. For the hybrid combination Bylinnaya × Olimpiyskaya Nadezhda, the percentage of seedlings with an Rpf1 resistance allele was 33.3%. For the combination Bylinnaya × Feyyerverk, their percentage was 37.2%; for Olimpiyskaya Nadezhda × Bylinnaya, 39.4%; for Privlekatelnaya × Bylinnaya, 39.6%; and for Feyyerverk × Bylinnaya, 36.2%. The average percentage of seedlings with an Rpf1 allele for the studied combinations was 37.1%. Assessment of the compliance between the observed segregation and theoretical one according to the χ2  criterion confirmed the monogenic character of the studied trait and the Mendelian ratio of inheritance frequencies for the marker fragments of the Rpf1 gene as 1 : 1. Therefore, all identified seedlings with an Rpf1 allele are characterized by a heterozygous genotype. Strawberry hybrids promising for breeding were identified: 62-41 (Bylinnaya × Feyyerverk), 65-17, 65-24 (Olimpiyskaya Nadezhda × Bylinnaya), and 69-29 (Feyyerverk × Bylinnaya).

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