Assessment of the adaptive potential of strawberry genotypes based on the development of endophytic microbiota and identified R-genes

The paper presents the results of a study of the strawberry genotypes (Fragaria L.) by characteristics of endophytic microbiota and genetic determinants of resistance to fungal pathogens. Highly adaptive genotypes were identified: F. virginiana Duch. ssp. platypetala, F. orientalis Los., F. ovalis Rydb., F. moschata Duch., 298-19-9-43, Urozhaynaya CGL, Flora, Privlekatelnaya and Troitskaya. These strawberry forms are characterized by a high frequency of testing of bacterial microbiota, which suppresses endophytic fungal pathogens. The wild strawberry F. virginiana Duch. ssp. platypetala is characterized by red stele root rot resistance (Rpf1 gene). Strawberry varieties Borovitskaya and Elianny are characterized by anthracnose resistance (Rca2gene).

Marker controlled screening of resistant to red stele root rot (Rpf1 gene) strawberry selected forms

The results of the analysis of allelic polymorphism of the Rpf1 red stele root rot resistance gene in strawberry hybrid forms using diagnostic DNA markers were shown. The recessive homozygous genotype (rpf1rpf1) was identified in strawberry seedlings 932-29 (F. virginiana subsp. platypetala (Rydb.) Staudt × Feyerverk), 933-4 (F. virginiana subsp. platypetala (Rydb.) Staudt × Rubinovyy kulon), 62-7, 62-23 (Bylinnaya × Feyerverk), 65-2, 65-15 (Olimpiyskaya nadezhda × Bylinnaya) and 35-16 (922-67 × Maryshka). The heterozygous state of the Rpf1 gene was identified in strawberry forms 69-29 (Feyerverk × Bylinnaya), 62-41 (Bylinnaya × Feyerverk), 72-24, 72-71 (Privlekatelnaya × Bylinnaya), 65-17, 65-24 (Olimpiyskaya nadezhda × Bylinnaya), which allows them to be used in breeding for resistance to P. fragariae var. fragariae as valuable initial forms.

Analysis of strawberry promising varieties and selected forms by resistance to red stele root rot using molecular markers

The analysis of the allelic state of the Rpf1 red stele root rot gene in 14 promising foreign strawberry varieties and 6 selected forms of the I.V. Michurin FSC breeding was completed. The Rpf1 gene in a heterozygous state was identified in strawberry forms 61-15 (Bylinnaya × Olimpiyskaya nadezhda), 69-29 (Feyerverk × Bylinnaya), and 72-71 (Privlekatelnaya × Bylinnaya), which makes it possible to recommend them for involvement in breeding work to create resistant to P. fragariae var. fragariae strawberry varieties. Strawberry varieties Lebedushka, Elianny, Florence, Malwina, Monterey, Polka, Verona, Vima Tarda Asia, Chamora Turusi, Clery, Flamenco, Salsa and Symphony, and selected forms 56-5 (Gigantella Maxim × Privlekatelnaya), 69-42 (Feyerverk × Bylinnaya) and 35-16 (922-67 × Maryshka) have a recessive homozygous genotype.

Analysis of strawberry genetic collection (Fragaria L.) for Rca2 and Rpfl genes with molecular markers

Strawberry (Fragaria x ananassa Duch.) varieties are susceptible to many fungal diseases. Identification of forms, carrying resistance genes, is an important stage in breeding programs leading to resistant varieties. The use of molecular markers allows to determine with high reliability the presence of the necessary genes in the genome and to identify promising forms. Some of the common strawberry's diseases, causing significant damage to strawberry plantations, are anthracnose (Colletotrichum acutatum Simmonds) and red stele root rot (Phytophthora fragariae var. fragariae Hickman). Dominant Rca2 gene is involved in monogenic resistance to C. acutatum pathogenicity group 2. Rpf1, Rpf2, Rpf3 genes are determined in monogenic resistance to red stele root rot. The purpose of this study was molecular genetic testing genotypes of genus Fragaria L. to identify carriers of Rca2 allele anthracnose resistance and Rpf1 allele red stele root rot resistance. The objects of study were the wild species of the genus Fragaria L. and strawberry varieties (Fragaria x ananassa Duch.) of different ecological and geographic origin. To assess allelic state Rca2 anthracnose resistance gene the dominant SCAR marker STS-Rca2_240 was used, was linked to the resistance gene Rca2 with a genetic distance of 2.8 cM. Rpf1 gene red stele root rot resistance was identified with the dominant SCAR marker R1A, was linked to the resistance gene Rpf1 with a genetic distance of 3.0 cM. The resistant allele of the marker STS-Rca2_240 was identified in the Laetitia variety (Rca2Rca2 or Rca2rca2 genotype), which allows us to recommend it as a promising source in breeding for anthracnose resistance. The other studied forms have homozygous recessive state of the marker STS-Rca2_240 (putative genotype rca2rca2). The resistant allele of the marker SCAR-R1A in the varieties and wild species of strawberry under study is absent, which presumably indicates their homozygous recessive genotype of Rpf1 gene (rpf1rpf1).