Identification of <i>Rca2</i> and <i>Rpf1</i> resistance alleles in strawberry breeding forms of intervarietal hybrid origin

Abstract

Background. The creation of varieties with genetic resistance to fungal pathogens is one of the most important directions in strawberry breeding. A promising direction of accelerated selection of valuable specimens is molecular screening for the presence in their genotype of diagnostic DNA markers, linked to target genes of agrobiological traits. Objectives of the work were determination of the allelic state of the Rca2 (resistance to anthracnose) and Rpf1 (resistance to red stele root rot) genes in selected strawberry forms to identify genotypes resistant to Colletotrichum acutatum Simmonds and Phytophthora fragariae var. fragariae Hickman.Material and methods. The object of research was breeding forms of strawberries of intervarietal hybrid origin. As a result of 22 crossing combinations, 61 selection forms were obtained, in which the allelic composition of resistance genes was studied. The Rca2 anthracnose resistance allele was identified by means of the STS-Rca2_240 marker. The Rpf1 red stele root rot resistance allele was identified with the help of SCAR-R1A marker. Results. At least one of the two genes was identified in 20 selected strawberry forms (32.8%). The STS-Rca2_240 marker was identified in 15 strawberry seedlings (22.9%) from six hybrid combinations ‘Vicoda’ × ‘Roxana’, ‘Florence’ × ‘Faith’, ‘Asia’ × ‘Aprica’, ‘San Andreas’ × ‘Monterey’, ‘Alisa’ × ‘Quicky’, ‘Quicky’ × ‘Olympia’). The SCAR-R1A marker was identified in five strawberry seedlings (8.2%) from four hybrid combinations (‘Privlekatelnaya’ × ‘Bylinnaya’, ‘Feyerverk’ × ‘Bylinnaya’, ‘Bylinnaya’ × ‘Feyerverk’, ‘Bylinnaya’ × ‘Olimpiyskaya nadezhda’). It has been established that all strawberry selected forms with identified marker fragments for resistance genes are characterized by a heterozygous combination of alleles.Conclusions. Promising sources of resistance alleles are strawberry selected forms: 2/1-24, 2/1-34 (‘Quicky’ × ‘Olympia’), 3/9-5 (‘Florence’ × ‘Faith’), 3/12-2, 3/12- 9 (‘Alisa’ × ‘Quicky’), 4/7-10, 4/7-19, 4/7-20 (‘Asia’ × ‘Aprica’), 5/2-26, 5/2-32 (‘San Andreas’ × ‘Monterey’), 9/ 1-11, 9/1-12, 9/1-13, 9/1-32, 9/1-37 ‘Vicoda’ × ‘Roxana’) in case of Rca2 gene; 72-24, 72-71 (Privlekatelnaya × Bylinnaya), 69-29 (‘Feyerverk’ × ‘Bylinnaya’), 62-41 (‘Bylinnaya’ × ‘Feyerverk’), 61-15 (‘Bylinnaya’ × ‘Olimpiyskaya nadezhda’) in case of Rpf1 gene.