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CNAA / Theses / 2017 / July /

Biological potential of Solanum lycopersicum L. genofond and its improving by breeding of valuable characters


Author: Mihnea Nadejda
Degree:doctor habilitat of biology
Speciality: 06.01.05 - Breeding and Seed Production
Year:2018
Scientific adviser: Galina Lupaşcu
doctor habilitat, professor, Institute of Genetics, Physiology and Plant Protection of the ASM
Scientific consultant: Vasile Botnari
doctor habilitat, associate professor (docent)
Institution: Institute of Genetics, Physiology and Plant Protection of the ASM

Status

The thesis was presented on the 21 July, 2017
Approved by NCAA on the 11 May, 2018

Abstract

Adobe PDF document – 1.31 Mb / in romanian

Thesis

CZU 635.64:631.52 (478) (043.2)

Adobe PDF document 16.00 Mb / in romanian
353 pages

Keywords

omatoes, genofond, breeding, quantitative and qualitative characters, low temperature, drought, fungal diseases, resistance, dominance, gene interactions

Summary

Field of study: Breeding and seed production.

Aim of the work: elucidation of the genetic basis of valuable characters of tomato (Solanum lycopersicum L.) and creation of varieties and lines adapted to the climatic conditions of Moldova.

Objectives: evaluation of Solanum lycopersicum L. germplasm based on the phenotypic variability of morphobiologic and agronomic characters and creating collections of forms with valuable traits; analysis of the gametophytic and sporophytic resistance to stressful temperatures in tomato advanced forms and clarifying its genetic determinism; determining of the genetic basis of such characters of tomato as resistance to abiotic factors, productivity, quality (morphobiological and biochemical), and the identification of advanced hybrid combinations; analysis of the reaction’s particularities of tomato forms with valuable morphobiological, agronomical, biochemical indications to thermal stressful factors and fungal pathogens (Alternaria spp., Fusarium spp.), and elucidation of genotypes with the complex of high-value characters.

Scientific novelty and originality of the work: multilateral study of the genofond of tomato Solanum lycopersicum L. in conditions of the Republic of Moldova has allowed the elucidation of the biological potential of some characteristics variability such as: productivity, morphological and biochemical quality of fruits, interphase periods, resistance to cold, scorching heat, some fungal diseases; it has been found that the created collection of tomato genotypes, with such valuable genes as u (uniform ripening), j (jointless), d (dwarf), which are important in controlling of the uniform fruit ripening, the fruit detaching from pedicel, the determinate type of plant growth, presents an extensive variability of different quantitative characters, that gives wide opportunities for real association of these genes with desired traits; it has been established that the phenomena of duplicate or complementary epistasis, that determine the duration of the breeding process, are different in depending on the combination and biological or agronomical characteristic of tomato.

Fundamentally new basic scientific and practical results. On the basis of a comprehensive study of the genofond of 800 genotypes of the tomato S. lycopersicum over the years, differentiated variability of morphobiological and economically valuable traits was established under different environmental conditions. This contributed to the successful development of its biological potential. For the first time a substantiation for the breeding process of tomato was developed using the identification of genetic factors controlling such valuable characteristics as productivity, quality, resistance to unfavorable biotic and abiotic factors. This ensured the purposes of the directed orientation and successful combination with genes controlling biological and economically valuable traits (u, jd), that contributed to the creation of new valuable lines and varieties released in the Republic of Moldova and abroad.

Theoretical significance: the estimation of the multiple regression coefficient β on the contribution of parental forms in the development of resistance of F1 hybrids of tomato to the high temperature (+ 43ºC) has found that the resistance of tomato sporophyte to the thermal stress is mainly determined by the maternal factor; duplicate epistasis is manifested in most combinations of tomatoes during the formation of phenotype of quantitative characters of productivity and morphobiology, which suggests that the phenomenon of the regulation of its level takes place due to the different orientation of dominants actions and dominant x dominants epistatic interactions; interphase period of tomato mass seedlings emergence - early flowering is controlled by factors of the negative overdominance, and high dependency exists between the degree of dominance of the growth period and the interphase period mass seedlings emergence - early flowering.

Applicative value: the genofond of tomato, which includes about 800 varieties and presents extended opportunities to improve some valuable characteristics of tomato, has been founded; 11 tomato varieties with high productivity, taste, and resistance to unfavorable environmental conditions have been development; 10 varieties have been released in the Republic of Moldova, 3 of them - in the Republic of Belarus (8 patented) and included into the database of the N.I. Vavilov Institute of Plant Genetic Resources (St. Petersburg).

Implementation of scientific results: the varieties of different ecological and geographical origin with economically valuable characters have been included in the national tomato breeding program for the obtaining of new varieties resistant to biotic and abiotic factors; used for research studies in laboratories of IGPPP ASM and Romania; introduced into different individual farms in the Republic of Moldova.