Open Access
Issue
BIO Web Conf.
Volume 21, 2020
XI International Scientific and Practical Conference “Biological Plant Protection is the Basis of Agroecosystems Stabilization”
Article Number 00028
Number of page(s) 6
DOI https://doi.org/10.1051/bioconf/20202100028
Published online 22 June 2020

© The Authors, published by EDP Sciences, 2020

Licence Creative Commons
This is an Open Access article distributed under the terms of the Creative Commons Attribution License 4.0, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

1 Introduction

Tomato is the most popular fruit crop in the world due to its wide range of use, nutritional value and unique taste [1–2]. However, biotic and abiotic factors hinder the commercial production of this culture when grown in open ground [3].

Among the biotic factors that can lead to significant yield losses of tomato crops, the most dangerous and harmful are fungi of the genus Alternaria sp. and oomycete Phytophthora infestans (Mont.) de Bary.

Recently, Alternaria sp. has become a leader in harmfulness among fungal diseases [4–6]. Damages of tomato plants caused by Alternaria sp. lead to yield losses, mold of seeds and fruits, and the metabolites of the fungus cause allergic reactions [7].

For many years, P. infestans oomycete has been recognized as the most dangerous pathogen in Russia, which reduces tomato yield up to 50 %, and in epiphytotic years up to 80 % or more [8–13]. Under the pathogen effect, the assimilation surface of tomato plants leaves decreases, fruits rot. The greatest damage was noted with increased humidity in open ground and in plastic-covered unheated greenhouses [14].

Cultivated tomato has a narrow genetic diversity, which was the result of its intensive selection and inbreeding during evolution. As a result, cultivated tomato species are more susceptible to disease than wild species and mutant forms. Thus, yield losses caused by pathogenic infections can be eliminated by developing resistant varieties with the help of plant breeding methods using the resistance genes of wild species and mutant forms of tomato [15–18].

To develop resistant varieties, breeders need tomato genetic collections with identified genes. One of such collections is supported at the FSBSI ARRIBPP, Krasnodar, where we comprehensively study the collection and select parent material for practical use in realizing the tasks of private selection [19].

Marker selection of the initial forms of tomato is a relatively new approach in breeding, which is based on the direct selection of plants by genes that determine economically valuable characteristics. As a result, the analysis of breeding material is carried out in a short time and most of the studied mutant forms can serve as a source of important economically valuable properties [20–23].

The aim of the study is to assess the resistance of mutant samples of the tomato genetic collection of the FSBSI ARRIBPP to diseases upon a provocative infectious background.

2 Materials and methods

As an experimental material, we used 22 samples from the collection of tomato mutant forms of the laboratory of the tomato genetic collection of the FSBSI ARRIBPP, Krasnodar (Table 1).

Screening of 22 test mutant tomato lines for resistance to Alternaria sp. and P. infestans was carried out in the field of FSBSI ARRIBPP in 2019 upon the provocative infectious background created as a result of the repeated cultivation in one place for three years, without the use of plant protection products, with plant residues embedded in the soil. Plants were placed in randomized blocks with three replications. Each replication included 10 plants of each genotype. Sowing pattern: 1.5 m × 0.75 m. There were no chemical treatments. Recording of diseases was carried out with the appearance of the first signs of the disease. Resistance of mutant lines to Alternaria sp. and P. infestans was assessed by the degree of damage according to the modified method [24–25]. Meteorological conditions of 2019 vegetation period were favorable for the growth and development of tomato. In July, increased humidity and high air temperature contributed to the intensive development of Alternaria sp. on tomato crops. P. infestans oomycete actively developed since the second half of August. The mass spreading of the pathogen was recorded in the second decade of September with a combination of optimal weather conditions: air humidity above 80 % at night, air temperature from + 20 °C to + 24 °C in the daytime.

The infestation area under the disease progression curve (AUDPC) was calculated for each genotype in each replication using an expanded modified formula [25]. Pearson correlation coefficients for various variables were calculated using the StatSoft Statistica V. 10.0 software package for statistical analysis.

Table 1

Tomato mutant forms from the collection of FSBSI ARRIBPP

3 Results and discussion

The first symptoms of Alternaria sp. in the form of dark spots were noted in the second decade of June. During the growing season, the disease developed in all aerial parts of plants. The intensity of Alternaria sp. development averaged 27.2 % (Table 2).

The first signs of P. infestans infection appeared in the second decade of August. On average, the intensity of P. infestans development was 48.1 % during the growing season (Table 2).

According to the results of the assessment of the tomato mutant lines for damage by Alternaria sp. in the field it was found that line 41 showed high resistance (HR), there were no signs of disease damage. Mutant lines 80, 387, 434, 568, 620 showed resistance (R), the degree of disease development ranged from 1-8 %. Lines 172, 467, 509, 518 with the development degree of 12–23 % were characterized by semi-resistance (SR). Lines 47, 60, 161, 341, 406, 411, 452 showed semi-susceptibility (SS) to the disease, with the development degree in the range of 27–36 %. Lines 45, 56, 350, 395, 445 were susceptible (S), the disease development degree ranged from 51–56 %.

Lines 41, 387 were characterized by high resistance to P. infestans. No visible signs of P. infestans damage were detected in these genotypes. Lines 341, 509, 518, 568 showed semi-resistance to the pathogen, the development degree varied from 10 to 18 %. Semi-susceptibility was shown by lines 80, 172, 434, 620. The disease development degree ranged from 27–42 %. The highest susceptibility was demonstrated by lines 45, 47, 56, 60, 161, 350, 395, 406, 411, 445, 452, 467 with the damage degree of 52-100 %.

As a result, lines with the highest field resistance to Alternaria sp. (41, 80, 387, 434, 568, 620) and P. Infestans (41, 387, 341, 509, 518, 568) had low AUDРC values. Significant correlation was noted (r = 0.98 at P <0.01). The relationship between the resistance of genotypes to diseases was average (r = 0.47-0.48 at P <0.05; r = 0.55-0.56 at P <0.05) (Table 3).

Table 2

Assessment of tomato mutant lines for damage by Alternaria sp. and P. infestans in the field, Krasnodar, 2019

Table 3

Pearson correlation coefficients for the assessment parameters of the tomato field resistance to Alternaria sp. and P. Infestans

4 Conclusions

According to the results of the conducted research, the damage assessment of 22 tomato mutant lines showed that lines 41 and 387 as sources of group resistance are of the greatest interest for further studies. These genotypes showed high resistance and relatively high resistance to the two diseases under study.

Studies on the resistance of tomato genotypes to P. infestans were carried out according to state assignment No. 075-00376-19-00 of the Ministry of Science and Higher Education of the Russian Federation as part of the research on the topic No. 0686-2019-0008, studies on the resistance of tomato genotypes to Alternaria sp. – under the RFBR grant No. 19-416-233022 r_mol_a.

References

All Tables

Table 1

Tomato mutant forms from the collection of FSBSI ARRIBPP

Table 2

Assessment of tomato mutant lines for damage by Alternaria sp. and P. infestans in the field, Krasnodar, 2019

Table 3

Pearson correlation coefficients for the assessment parameters of the tomato field resistance to Alternaria sp. and P. Infestans

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