Fruit growing
and viticulture of South Russia

Annotation

Improving the fruit aroma is one of the promising directions of modern strawberry breeding. The strawberry fruit aroma is a complex trait, formed by a combination of a large number of volatile compounds. The present study shows the results of assessing the allelic state of the FaOMT gene, determining biosynthesis of mesifurane (volatile compound) in strawberry selected forms created in the �I.V. Michurin FSC�. The biological objects of the study were 22 strawberry selected intervarietal forms from 12 crossing combinations. The allelic state of the FaOMT gene was identified using codominant SCAR marker FaOMT-SI/NO. As a result of the studies, the marker fragment of the functional allele FaOMT+ was identified in 86.4 % of forms. A heterozygous combination of alleles of the FaOMT gene (average level of mesifurane accumulation in fruits) was detected in 9.1 % forms. The homozygous state of the functional allele was detected in 77.3% forms. The homozygous state of the non-functional allele FaOMT- (mesifurane is not produced) is characterized by three genotypes (13.6 %). The greatest value for strawberry breeding use are forms with the homozygous state of the FaOMT+ allele: 1/6-41 (Vima Zanta × Polka), 2/2-32, 2/2-41 (Faith × Tea), 3/2-62 (Vima Zanta × Privlekatelnaya), 3/4-6, 3/4-7 (Malwina × Tea), 3/9-5, 3/9-12 (Florence × Faith), 5/1-105 (Polka × Vima Zanta), 5/2-23, 5/2-26, 5/2-32 (San Andreas × Monterey), 6/3-5, 6/3-21 (Kimberly × 9/2-2), 7/2-78 (Asia × Maya), 9/2-2, 9/2-7 (Kimberly × Honeoye). These forms are characterized by the maximum level of mesifurane biosynthesis in fruits and their involvement of which in hybridization allows the transmission of the target allele to 100 % of the hybrid seedlings.

Annotation

Powdery mildew, white and brown spots, as well as recent anthracnose black rot, late blight and verticellosis wilt are the most important diseases that cause the significant damage to the strawberry plantations. The losses of a strawberry commodity crop from anthracnose damage can reach 80 %. The most strawberry varieties are susceptible to anthracnose black rot in various degree. The resistance of garden strawberry to anthracnose is controlled polygenically and monogenously. The causative agent of late blight root rot (late blight wilting) is Phytophthora fragariae var. fragariae Hickman. The causative agent of late blight affects the root system, causing the inhibition of growth, withering and subsequent death of plants. One of the promising methods for identifying wild strawberry forms resistant to late blight and anthracnose is analysis using diagnostic DNA markers linked to the target alleles of resistance genes. DNA markers are successfully used both at the stage of selection of initial sources for hybridization and in the subsequent analysis of hybrid material. The results of DNA analysis of varieties and selected seedlings of strawberry on the genes of resistance to late blight wilt Rpf1 and anthracnose Rca2 are shown. The SCAR-R1A marker linked to the Rpf1 gene was not detected in the studied strawberry varieties and forms, that presumably indicates their recessive homozygous genotype for the Rpf1 gene (rpf1rpf1). The STS-Rca2_240 marker linked to the Rca2 gene was detected in Borovitskaya and Aprica varieties and in the selected form of 933-4 (F. virginiana Duch. Ssp. Platypetala × Rubinovy Kulon), which allow us to recommend them for breeding as a promising source of anthracnose resistance.

Annotation

Methodical aspects for the selection of strawberry genotypes with high anthocyanins content have been developed. They are based on a generalize of long-term studies of the anthocyanins accumulation in the fruits of a large number of varieties, elite and selected forms and hybrid material, carried out both in the field and in the laboratory. An improved color scale is presented, consisting of 15 color photographs of samples that more fully reflect the entire spectrum of fruit color changes from light to dark shades associated with less or greater accumulation of anthocyanins. The developed estimation scale makes it possible to carry out a field rapid estimation of the anthocyanins content in the strawberry fruits of both the numerous genetic collections and the hybrid fund. The reliability of this method is confirmed by a high correlation (r = +0.82) between the fruit anthocyanins content determined in the field using the color scale carried out for 457 strawberry forms and then that determination by the differential spectrophotometry. A gradation of the analyzed genotypes depending on the anthocyanins content is including 5 groups from very low (30.0 mg/100g and below) to very high (90.1 mg/100g and more). As a result of the research, promising strawberry varieties and forms (Rubinovyy Kulon, Privlekatel'naya, Feyyerverk, 3/3-16 (Feyyerverk × Maryshka), 3/6-72 (Rubinovyy Kulon × Maryshka), 3/2-3 (Feyyerverk × L'vovskaya Rannyaya)) � the sources of high anthocyanins content suitable for fresh consumption, processing and freezing, and further breeding on the improved chemical composition of fruits were identified.

Annotation

Anthracnose black rot caused by phytopathogenic fungi of the genus Colletotrichum is one of the most widespread diseases of strawberry, causing a significant damage to industrial plantations. The defeat of strawberry with anthracnose can lead to the loss of more than 80% of the crop. Most of the strawberry varieties intended for industrial cultivation are susceptible to anthracnose black rot in various degree. This study presents the results of PCR analysis of varieties and forms of strawberry (F. × ananassa Duch.) taking into account the Rca2 gene of resistance to anthracnose. Biological objects of research were the cultivars of garden strawberry of various ecological and geographical origin and perspective selective forms of FSBSI �FSC I.V. Michurin� breeding. To assess the allelic state of the Rca2 gene of strawberry stability to anthracnose SCAR marker STS-Rca2_240 was used. The PCR process was monitored by the SSR marker of EMFv020. The article shows the results of DNA analysis of varieties and selected seedlings of strawberry using the Rca2 gene of resistance to anthracnose. Based on the evaluation of the allelic state of the Rca2 gene, the Laetitia strawberry variety is resistant to anthracnose (the supposed genotype Rca2Rca2 or Rca2rca2), which allow us to recommend it for breeding as a promising source of resistance to C. Acutatum Simmonds of the 2nd pathogenic group. The other analyzed genotypes have a recessive homozygous status on the marker STS-Rca2_240 (the supposed genotype Rca2Rca2), which indicates their susceptibility to the causative agent of anthracnose black rot of the 2nd pathogenic group.

Annotation

The aroma of fruits is an important consumer trait of strawberry varieties. Among the most important aromatic substances contained in strawberry fruits is γ-decalactone, which has a peach-like, fruity sweet aroma. The present study shows the results of the molecular genetic analysis of strawberry varieties and selected forms created in the "I.V. Michurin Federal Scientific Center", according to the FaFAD1 gene involved in the biosynthesis of γ-decalactone, to identify promising genotypes for breeding to fruit aroma. The biological objects of the study were strawberry varieties and selected forms of the breeding "I.V. Michurin FSC": Lastochka, Privlekatelnaya, Urozhaynaya CGL, Feyyerverk, Flora, Yarkaya, 26-5 (Rubinovyy kulon × 298-19-9-43), 56-5, 56-8 (Gigantella Maxim × Privlekatelnaya), 61-12 (Bylinnaya × Olimpiyskaya nadezhda), 72-25 (Privlekatelnaya ×Bylinnaya), 928-12 (298-19-9-43 × Privlekatelnaya), 932-29 (F. virginiana subsp. platypetala (Rydb.) Staudt × Feyyerverk) and 298-19-9-43 (FB2 F. orientalis Los., F. moschata Duch., F. × ananassa Duch.). Genomic DNA extraction was carried out from young leaves according to the modified CTAB method. The FaFAD1 gene was identified with dominant DNA marker FaFAD1. As the result of the molecular genetic research, the following strawberry selected forms, promising for breeding to improved fruit aroma, were identified: 72-25 (Privlekatelnaya × Bylinnaya), 56-8 (Gigantella Maxim × Privlekatelnaya), 61-12 (Bylinnaya × Olimpiyskaya nadezhda), which are characterized by the presence of a functional allele of the FaFAD1 gene. The strawberry selected form 72-25 (Privlekatelnaya × Bylinnaya) is additionally characterized by the presence of the FaOMT gene in the heterozygous state, so this form is a complex source of fruit aroma genes (FaOMT and FaFAD1).