0ne of the most important issues of breeding is development of new varieties

in which to assemble more valuable characters, high productivity, increased

resistance to unfavorable environmental factors and precocity with large and

qualitative fruits. However, to accelerate the process of creating such varieties,

it is necessary to apply new selection methods and technologies.

We mentioned that a real perspective in this aspect was presented by the

modern biotechnology methods and techniques, based on the principles of

molecular genetics, genetic and cellular engineering, cell cultures and vegetal

tissues, accelerated micro-propagation, induced variability and somaclonal

variability, remote hybrids.

Remote hybridization methods with the mobilization of the spontaneous

genofond and the application of the in vitro culture allowed us to settle many

issues in the amelioration process. Through classical hybrids, efficient capacities

have been transferred to the activity of plant regeneration by crossing

spontaneous species with the crop species through the embryo calus culture.

The hybridization of different genetically-stable species varied according

to the degree of kinship between them, with the transmission of genetic information

that results in some valuable economic carcasses from spontaneous

species to culture species. Thus, the emergence of biotechnologies, especially

in vitro culture, produced a real revolution in the process of improving

vegetable crops and other agricultural species.

The research was carried out within the Plant Resistance Genetics laboratory

of the Institute of Genetics, Plant Physiology and Plant Protection. As a

subject of study, 7 varieties of tomato were produced, created through interspeci

fic crosses and application of in vitro culture. (‘Iulihirsutian’, ‘Iuliperuan’,

‘Anatolia’, ‘CerryDani’, ‘Jacot’) approved in the Republic of Moldova, (‘Flacara’

and ‘Mia’) were tested at the State Commission for Testing Plant Varieties.

The evaluation of the native varieties was carried out according to the

most valuable biochemical qualitative indices (dry matter content, sugar

content, ascorbic acid acicide content, titratable acidity and sugar/acidity

ratio). As a control variety, the varieties (‘Solearis’, ‘Elvira’, ‘Peto-86’ and

‘Novinca pridnestrovia’) were used. At the assembly of experiments there

were used seeds and seed culture. Estimating the dry matter content and

the percentage of sugar in tomatoes was performed using the refractometer.

As a result of the application of remote hybrids and in vitro culture, varieties

(‘Iulihirsutian’, ‘Iuliperuan’, ‘Anatolie’, ‘CerryDan’i, ‘Jacot’) approved in the

Republic of Moldova (‘Flacara’ and ‘Mia’) were tested at the State Commission

for Testing of Plant Varieties.

The results of the investigations showed that local tomato varieties surpassed

the check varieties (‘Solearis’, ‘Elvira’, ‘Peto 86’ and ‘Novinca pridnestrovia’)

by the following characters – the dry matter content, sugar content

and total acidity. As a result of the remote hybridization the interest

for the breeders also provided the spectrum of genetic heredity variability,

which increases the efficiency of selection of genotypes with high productivity

and increased resistance to environmental stressors. One of the main

tasks of the improvement was the gorgeous fixing of several characters (productivity,

precocity and high quality of fruit to stress factors (drought and

low positive temperatures).

The study of the obtained results demonstrated that the limits of variability

of biochemical components content, which determined the quality of

the fruits, were very large. Of particular interest was the early average varieties

characterized by an increase in the dry matter content, eg. the latter

in the variety (‘Iuliperuan’) increased by 17 % compared to the check variety

‘Solearis’ and ‘Iulihirsutian’ by 20 % against the check variety ‘Elvira’). These

varieties possessed superior qualities of the dry matter content with the

variability of 13.33 % and 14.13 %. In late varieties (“Anatolie and Jacotta”)

the variation coefficient oscillated between 12.03 to 8.14 %.

The early variety (‘CerryDani’) exceeded the check variety (‘Peto-86’) by

14.24 %. Concerning the percentage of sugar content the maximum values

against the check varieties accumulated the early average varieties.

The sugar content of the tomato varieties constituted 5.32 to 7.10 % with

different values of the variation from 5.86 to 10.63 % compared to the check

varieties of 4.89 to 6.39 % as well as the coefficient of variation 5.87 to 10.79 %.

The use of the genetic potential of spontaneous forms was also of great

importance for increasing the size, shape and quality of the fruit with high

vitamin C content.

Biochemical determinations of ascorbic acid (vitamin C) were also of great

importance because they determined the quality of fruits that had high taste

qualities. The biochemical content of ascorbic acid in tomato fruits showed

a very high variability. Noteworthy that the indices of vitamin C content in

tomato varieties formed the limit of variability of 9.66 to 34.15 % compared

to check varieties of 8.43 to 24.03 %. .

In assessing new tomatoe varieties the ratio of sugars to acidity was a very

important one, because this indice determined the taste properties of the fruits.

Based on the data obtained previously and taking into account the speci

fic biochemical properties characterized by the accumulation capacity of

the maximum volume of dry matter, sugar and, in particular, ascorbic acid

(vitamin C), the varieties mentioned were to be used in the improvement

programs as donors of valuable biochemical peculiarities of the fruits.

According to the investigations carried out by the application of in vitro

culture, there was a harmonization of recombinant genes, possessing some

precious qualities that allowed creating high performance varieties, fruits

with high taste qualities, distinct technological qualities and increased resistance

to drought, low positive temperatures and diseases.