Pyramided ph2 and ph3 genes for breeding tomato tolerant to late blight and evaluating the horticultural characteristics of some tomato lines in early winter season 2020 in red river delta

GRADUATION THESIS Pyramided Ph2 and Ph3 genes for breeding tomato tolerant to late blight and evaluating the horticultural characteristics of some tomato lines in early winter season 2

GRADUATION THESIS

Pyramided Ph2 and Ph3 genes for breeding tomato

tolerant to late blight and evaluating the horticultural characteristics of some tomato lines in early winter

season 2020 in Red River Delta

Dr Trần Ngọc Hùng

Hanoi, 28th February, 2021

Student

Nguyen Xuan Khanh

Assoc Prof Vũ Thị Thu Hiền -Head of Department of Genetic and Plant breeding, Vietnam National University of Agricultural (VNUA) and Dr Trần Ngọc Hùng-Head of Department of Biotechnolog, Fruit and Vegetable Research Institute, for the continuous support of my graduation thesis, for their patience, motivation, and immense knowledge Their devoted guidance helped me in all the time of research and writing of this thesis Besides my supervisors, I would like to thanks to The Fruit and Vegetable

Research Institute for giving me an opportunity to access to the laboratory and research facilities In the other hand, I am also grateful to people working in here for sharing their experiences, time during my work Without their precious support, it would not be

possible to conduct this thesis

I would also like to express my indebtedness to all the teachers who taught me during the past studying and equipped me with the knowledge as the basis for conducting

my thesis as well as in real life

My sincere thanks also go to teachers in faculty of Agronomy, Vietnam

National University of Agriculture for their insightful comments and encouragement Besides that, I am thankful to my dear classmates, class K61KHCTT, for all the fun, friendship we had in the last four years

Last but not least, I would like to thank my family for supporting me

spiritually throughout my studying and life in general

Hanoi, 28th February, 2021 Student

Nguyen Xuan Khanh

LIST OF TABLES VII

2.1 ORIGIN, DEVELOPMENT HISTORY, AND CLASSIFY 3 2.1.1 ORIGINS, DEVELOPMENTAL HISTORY 3

2.4 THE SITUATION OF TOMATO PRODUCTION IN THE WORLD AND

2.5.2 THE SITUATION OF TOMATO RESEARCH IN VIETNAM 19

3.3.1 EVALUATING THE HORTICULTURAL CHARACTERISTICS OF

SOME TOMATO LINES IN EARLY WINTER SEASON 2020 IN

3.3.2 PYRAMIDING PH2 AND PH3 GENES FOR BREEDING TOMATO

3.4.4 PRODUCTIVITY AND YIELD COMPONENTS 30 3.4.5 EVALUATION OF RESISTANCE TO LATE BLIGHT DISEASE 30

4.1 HORTICULTURAL CHARACTERS OF SELECTED PLANTS 32 4.1.1.TIME TO COMPLETE THE GROWTH AND DEVELOPMENT

4.1.1.1 TIME FORM SEEDLING TO FIELD PLANTING 34

4.1.1.2 TIME FROM FIELD PLANTING TO FLOWERING 34 4.1.1.3 TIME FROM FIELD PLANTING TO FRUIT RIPENING 35 4.1.2 MORPHOLOGICAL CHARACTERISTICS OF PLANT STRUCTURE

36 4.1.2.1 GROWTH SHAPE AND PLANT HEIGHT 38 4.1.2.2 FLOWERING CHARACTERISTICS AND FLOWER CLUSTER

4.1.4 FACTORS CONTRIBUTING TO THE PRODUCTIVITY OF

TOMATO VARIETIES IN EARLY WINTER SEASON 2020 44

REFFERENCES 56

LIST OF TABLES

TABLE 2.1 SUMMARY OF MAIN FUNCTIONS OF PLANT NUTRIENTS:

10 TABLE 2.2 TOMATO ACREAGE, PRODUCTION AND PRODUCTIVITY

TABLE 2.3 TOMATO ACREAGE, PRODUCTION AND PRODUCTIVITY

OF DIFFERENT CONTINENTS IN 2014-2018 13 TABLE 2.4 TOMATO ACREAGE IN VIETNAM IN THE PERIOD 2012 -

TABLE 2.5 TOMATO PRODUCTION IN VIETNAM IN THE PERIOD 2012

TABLE 4.1 THE GROWTH AND DEVELOPMENT STAGES OF TOMATO

VARIETIES IN THE EARLY WINTER 2020 SEASON 32 TABLE 4.2 SOME OF MORPHOLOGICAL CHARACTERISTICS OF

TABLE 4.4 FACTORS CONTRIBUTING TO THE PRODUCTIVITY OF

TOMATO VARIETIES IN EARLY WINTER SEASON 2020 44 TABLE 4.5 THE RESISTANCE TO LATE BLIGHT DISEASE OF TOMATO

LINES AFTER PYRAMID PH2 AND PH3 GENE 51 TABLE 4.6 HORTICULTURE AGRICULTURE CHARACTERISTICS OF

F5 TOMATO LINES CARRYING PH2 AND PH3 GENES 53

LIST OF FIGGURE

FIGURE 1 ELECTROPHORESIS IMAGE OF TOMATO LINE F5

HOMOZYGOUS FOR PH2 GENE BY UF-PH2-1 DIRECTIVE 49 FIGURE 2 IMAGE ELECTROPHORESIS IDENTIFIED TOMATO LINES

HOMOZYGOUS F5 GENE BY DIRECTIVE PH3 PH3-GSM1 50 FIGURE 3 EXPRESSION OF RESISTANCE TO LATE BLIGHT DISEASE

ABSTRACT

The study was carried out from August 2020 to the end of February 2021 at the Fruit and Vegetable Research Institute, Trau Quy – Gia Lam – Ha Noi We conducted two

experiments In the first one, we studied to select plants carrying genes Ph2 and Ph3

governing Leaf Blight disease resistant Our result show that the the disease resistance of F5 tomato lines carrying both Ph2 and Ph3 genes was higher than that of parents which carrying only 1 gene, and these lines are good materials for tomato breeding In the second experiment, we evaluated the horticultural characteristics of some tomato lines in early winter season Most of the varieties have good growth and development, especially experimental varieties such as TC-1, TC-2 and TC-3 have outstanding horticulture characteristics compared to the control varieties

Chapter 1: Introduction 1.1 Introduction

Tomato (Solanum lycopersicum L.) classified in solanaceous (Solanaceae)

family together with tobacco, potatoes, peppers, eggplant originating in Central, South and South North America Today, tomatoes were produced in most countries around the world with thousands of different varieties, diversity of color, fruit shape, growth habits Tomatoes are used in many different forms, such as fresh food, making salad, drinks Processed products are also types such as canned peeled fruits, concentrates, ketchup, tomato sauce, tomato jam Tomatoes are vegetables with high nutritional value, containing many glucose, organic acids, and are a source

of important antioxidants like lycopene, phenolic, Vitamin C…

Because of the wide adaptability, high nutritional and economic value, tomatoes are one of the key vegetable crops prioritized for development in the world Tomato acreage and yield are constantly increasing each year In Vietnam, tomatoes are grown in many places such as: Traditional vegetable growing areas of the Red River Delta (Ha Noi, Nam Dinh, Hai Phong, Hai Duong ) and Lam Dong are the places where many tomatoes are grown most in the country In our country, tomatoes are grown in 3 seasons / year and winter season is main one

However, the production of tomatoes in our country still faces many problems due to low productivity and quality of tomatoes, the consumption market is mainly domestic In particular, the price of tomatoes in the main season is very low, often only about one-third or a quarter of the off-season price

Besides, the diseases, especially late blight, is one of the biggest issues the farmer must be faced Late blight disease is caused by the fungus named

Phytophthora infestan, identified as a hazardous major in tomato production in the

tropics and subtropical (Lima et al., 2009; Elsayed et al., 2012) Fungus cause

damage all parts of the plant: leaves, stems, fruit in all stages of growth, reducing yield and quality (Lievens et al., 2004) Most fungicides do not work when disease occurs, so using resistant tomato varieties is the most optimal solution for controlling late blight disease Some tomato varieties are resistant to late blight generated by introducing disease-resistant genes from wild tomato cultivars (Panthee and

Gardner, 2010) and Ph2 and Ph3 are the names of two resistant genes which are used

to create them

Therefore, our goal is breeding new tomato leaf blight resident varieties which is also high yield, good quality and growing well in off-season On the basis,

I am going to perform thesis:

“Pyramided Ph2 and Ph3 genes for breeding tomato tolerant to late blight

disease and evaluating the horticultural characteristics of some tomato lines in early winter season 2020 in Red River Delta”

1.2 Purpose

-Identify the high yield and good quality plants for production in early winter season 2020 in Red River Delta

- Identify the disease resistance of the lines / varieties carrying genes Ph2, Ph3

governing late blight resistance

1.3 Requirements

- Evaluation and selection the plants of good horticultural characters

- Evaluation the disease resistance of the lines / varieties carrying genes Ph2, Ph3 governing late blight resistance

Chapter 2: Literature Review

2.1 Origin, development history, and classify

2.1.1 Origins, developmental history

The tomato is the edible, often red, berry of the plant Solanum lycopersicum,

commonly known as a tomato plant The species originated in western South America and Central America The Nahuatl (the language used by the Aztecs) tomato gave rise to the Spanish word tomato, from which the English word tomato derived Its domestication and use as a cultivated food may have originated with the indigenous peoples of Mexico The Aztecs used tomatoes in their cooking at the time

of the Spanish conquest of the Aztec Empire, and after the Spanish encountered the tomato for the first time after their contact with the Aztecs, they brought the plant to Europe From there, the tomato was introduced to other parts of the European-colonized world during the 16th century (Garden Tomato,2014)

Tomatoes were brought to Asia in the 18th century, first in the Philippines, East Java (Indonesia) and Malaysia in Europe Some researchers believe that tomatoes are imported into Vietnam from the time of the French occupation Despite its long history, until the first half of the 20th century, tomatoes became truly popular

in the world (Morrison, 1998)

2.1.2 Classify

According NCBI

Kingdom: Plantae Phylum: Tracheophyta

Class: Magnoliopsida Order: Solanales Family: Solanaceae Genus: Solanum

Species: S lycopersicum Tomatoes belong to genus Lycopersicum, family Solanaceae, has

chromosome 2n = 24 There are many ways to classify tomato plants, but according

to the Brezhnev classification (1964) is most commonly used With the Brezhnev classification, the Lycopersicon Tourn is divided into three species belonging to two

subspecies, including the Lycopersicon esculentum Mill belonging to the second subspecies Eulycopersicon It is one year old, the stem is 30-300cm high, the leaves

are divided into round or oval leaves This species belongs to 3 subspecies and

tomato belongs to L esculentum Mill.ssp.cultum It consists of 4 species:

- L esculentum var vulgare Brezh Normal form

- L esculentum var validum (Bailey) Brezh Dwarf stiffness stem form

- L esculentum var gradifolium (Bailey) Brezh Big leaf form

- L esculentum var Congregation Mixed form

2.2 Tomato value

2.2.1 Nutritional and medical value

Tomatoes are a fruit and vegetable with a high nutritional value Among the categories vegetables , tomatoes are foods that contain vitamins, minerals and many bioactive substances, and are healthy foods According to nutritionists, each day

using 100-200 grams of tomatoes will satisfy the needs of essential vitamins and major minerals

Beside the great content about nutrition, tomatoes also have a great significance in terms of medicine According to traditional medicine, tomatoes have

a sweet and sour taste, cool properties, are used to heat, refresh, moisturize and cool the blood, often used to treat diseases such as heat, dry lips, thirst due to the taste of heat or dizziness, nosebleeds, bleeding teeth, poor digestion, stomach ulcers, high blood pressure Tomatoes are indicated for eating or taking fruit juices to treat depression, appetite, poisoning chronic, excess blood, too sticky blood, arteriosclerosis of the arteries, organs joints, rheumatism, rheumatism, excess urea

in the blood, enteritis… According to Vo Van Chi (2002), tomatoes provide energy, provide minerals, increase vitality, balance cells, appetizers, cool off, antiseptic (scurvy), anti-bacterial, anti-toxic, alkaline blood is too acidic, diuretic, urea excretion, help digestion starch easily

In tomatoes, lycopene - which component that makes up the red color of tomatoes helps reduce the risk of cardiovascular disease This is a natural antioxidant that is 100 times more potent than vitamin E-related lycopene, which has been shown

to prevent prostate cancer With more tomatoes, the rate of oxidation damage to biochemical structures of DNA is lowest For women, eating a lot of tomatoes will have healthy and beautiful skin, reducing obesity and the risk of breast cancer

2.2.2 Economic value

Tomatoes can be eaten fresh instead of fruit, mixed with salts, cooked, or as the main ingredient for various food processing such as tomato concentrate, ketchup, mushroom sauce, canned tomatoes, jam or juice Therefore, for countries around

the world in general and in tropical countries, including Vietnam, the tomato plant

is one of the most potential and economically productive crops and an important export commodity

The global tomato market revenue amounted to $190.4 billion in 2018, rising

by 6.5% against the previous year This figure reflects the total revenues of producers and importers (excluding logistics costs, retail marketing costs, and retailers' margins, which will be included in the final consumer price) The market value increased at an average annual rate of +3.1% from 2007 to 2018 (Researchandmarkets, 2021)

Tomato was first cultivated about 100 years ago in Vietnam Because tomato

is one of the target vegetables for export together with other kinds of vegetables such

as cucumber, corn, and beans, the tomato area has been increasingly expanded in recent years The area of tomatoes in recent years has fluctuated in the range of 23-

25 thousand hectares In 2019, the total value of Vietnam's tomato exports reached more than 5 billion USD The two main markets are Malaysia and Singapore, accounting for 55.6% and 39.1% of the total value respectively Tomato production

is usually four times more profitable than growing rice

2.3 Characteristics and development conditions of tomato

2.3.1 Tomato characteristics

Tomatoes are diploid plants with chromosome 2n = 24, which are characterized by traits:

which the tomato root field conditions can be eaten up to 1.3 m wide and up to 1m deep With such root weight, tomatoes are classified as drought tolerant The

regeneration ability of tomato roots is strong When the roots are cut off, the secondary roots thrive so that we can uproot seedlings from the nursery to plant out

of the production field without fear of death

• Stem: The stem of the tomato is angular, thick at the internodes and pubescent Of grassy consistency at the beginning of growth, it tends to become a little woody with age (Dr Afsheen Siddique, 2018) Based on growing characteristics, tree height can be classified into 3 types: short type (under 65cm), medium type (from 65cm - 120cm), and high type (from 120cm - 200cm)

• Leaves: The leaves of the tomato are alternate , 10 to 25 cm long, composed and include 5 to 7 leaflets with very lobed lobes (Dr Afsheen Siddique, 2018).Between the leaflets there is also a middle leaf, on the base of the leaflets there are small leaves called lateral leaves Depending on the variety, the leaves of tomatoes vary in color and size

stamens and stigma) Tomatoes are mainly self-pollinating Their calyx, which has five green sepals, is persistent after fertilization and remains at the top of the fruit Their corolla has five bright yellow petals, fused at the base, often reflected backwards, forming a five-pointed star Their elongated anthers form a cone constricted around the pistil It consists of two fused carpels, forming a double biliary superior ovary Note that in some varieties of tomatoes, the ovary is plurilocular

• Fruit: Tomato fruit of the berry category include peel, flesh, septum, ovule Fruit usually have 2, 3 or more seed compartments Fruit shape and color depend on the variety In addition, the color of ripe fruit depends on the carotene and lycopene content The high carotene content gives tomatoes a yellow color, while lycopene gives a red color

2.3.2 Development conditions of tomato

Plants in general and tomatoes, during their growth and development, tomato plants suffer a lot of the impact of external conditions such as soil, temperature, humidity, light,

2.3.2.1 Temperature

Temperature affects the growth and development of tomatoes In general, values between 18.3 and 32.2°C are optimal air temperatures for tomatoes during the entire growing season The optimal air temperature for tomato germination is recommended to be at 25°C The ideal air temperature for seedling growth should

be between 16 and 18.5°C Moreover, the rate of fruit addition (fruit-set, from pollination) had an optimum air temperature at or lower than 26°C and progressively failed with temperature reaching 32°C Finally, air temperatures of 18.5-26.5°C with day and night temperatures, respectively, between 21-29.5°C and 18.5-21°C were

reported to be optimal (Redmond Ramin Shamshiri, et al., 2018) Review of

optimum temperature, humidity, and vapor pressure deficit for microclimate evaluation and control in greenhouse cultivation of tomato: a review pg3)

2.3.2.2 Humidity

Water is a very important factor affecting the intensity of basic physiological processes: photosynthesis, respiration, growth and development The favorable soil moisture for tomatoes is 60-70% of field humidity, humidity suitable air is 45 - 55% High humidity reduces resistance to pests and diseases, unfavorable conditions; The

water content in the fruit is high, the content of dissolved substances is reduced, the ripe fruit has poor ability to preserve and transport

2.3.2.3 Light

The light intensity is suitable for tomatoes to grow and grow from 10,000 lux Plants that lack light or grown in low light conditions will be weak, small leaves, thin, rhubarb, slow flowering, poor fruiting, reduced yield and fruit quality, pale flavor Red light accelerates leaf growth and suppresses lateral shoot growth, promotes lycopene and carotene production Green light increases dry matter most strongly

4,000-2.3.2.4 Soil and nutrient

Low fungus-free soil is a very basic condition for growing tomatoes with high yield and quality The soil suitable for tomato plants is light fleshy soil, sandy soil, porous, easy to irrigate, pH from 5.5 to 7.5 The most suitable pH for tomatoes to grow and develop is 6 - 6.5

Nutrients are key aspects of tomato production for optimum yield and fruit quality Tomatoes need at least 12 elements phosphorus (P), potassium (K), sulfur (S), magnesium (Mg), Bo (B), iron (Fe), manganese (Mn), copper (Cu), zinc (Zn), molybdenum (Mo) and calcium (Ca) Their main function is below the table:

Table 2.1 Summary of main functions of plant nutrients :

enzymes, reduces susceptibility to plant diseases

susceptibility to diseases

pollen tubes

Participates in the metabolism and transport of sugars

Copper (Cu) Influences in the metabolism of nitrogen and carbohydrates

Molybdenum (Mo)

Component of nitrate-reductase and nitrogenase enzymes

https://www.haifa-group.com/crop-guide/vegetables/tomato/crop-guide-tomato-plant-nutrition

Nitrogen, phosphorus and potassium are 3 types most essential nutrients for tomato plants Tomatoes absorb the most potassium, followed by protein and at least phosphorus Tomatoes use 60% of the amount of N, 50-60% of K20 and 15-20% of P205 of the total fertilizer into the soil during the growing season To be able to adequately and timely provide tomato plants, we need to understand the nutritional needs of plants and the nutrient supply capacity of the soil to grow tomatoes Thus, the yield of new tomatoes is high and stable

2.4 The situation of tomato production in the world and in Vietnam

2.4.1 The situation of tomato production in the world

Although tomatoes have a relatively late development history, they possess a wide adaptability and high value for use Therefore, the production and use of tomatoes increased continuously Tomato has become a powerful crop bringing high economic efficiency to many countries around the world In the world, many new varieties have been released to meet the increasing demand of people in both quantity and quality

Table 2.2 Tomato acreage, production and productivity of different

(source: FAO Database Static 2016)

According to Table 2.3, in 2014, Asia had the tomato growing area of 2,836.26 thousand hectares and had the largest output of 101,638.89 thousand tons in the world However, the productivity achieved (35.84 tons / ha) is just above Africa (15.86 thousand tons) The Americas and Oceania have less cultivated areas but have significantly higher yields This shows the achievements that modern agriculture has brought about clear results

Table 2.3 Tomato acreage, production and productivity of different

continents in 2014-2018

(thousand ha)

Production (thousand tons)

Productivity (tons/ha)

Tomato production in the world has been steadily increasing year by year from 174.79 million tons (2014) to 182.26 million tons (2018) However, world tomato yields have not changed steadily since 2014 to 2018 In which, 2018 was the year

with the highest productivity with 38.27 tons / ha, followed by 2017 (37.33 tons / ha), but the year before, the production of tomatoes was 35.54 tons / ha There is a difference that is due to the influence of technological advances on tomato yields

2.4.2 The situation of tomato production in Vietnam

In Vietnam, tomatoes have only been grown for over 100 years, the development history is still very young compared to the world, but with favorable weather conditions suitable to grow tomato plants and bring economic benefits At present, tomatoes are grown in most provinces and cities with many seasons per year

Table 2.4 Tomato acreage in Vietnam in the period 2012 - 2016

Northern Midlands and Mountains

(source: General Statistics Office,2017)

The national tomato acreage has decreased in the last 2 years due to the decrease in the planted area in the South and the relatively stable tomato acreage in the North In the South, tomato production in all regions, but concentrated mainly in the Central Highlands, accounts for about 70% of the area, of which mainly distributed in Lam Dong province Lam Dong province has the largest tomato growing area in the country, in the last 5 years, the enemy in 2013 planted the most

at 9.3 thousand hectares, equivalent to 36.5% of the country's tomato area Although the area has decreased, the average tomato yield across the country has tended to increase slightly in recent years, followed by a constant increase in tomato production

Table 2.5 Tomato production in Vietnam in the period 2012 - 2016

(source: General Statistics Office,2017)

In the Northern, tomatoes are grown in all three regions of the delta, midland and mountain, but mainly in the Red River Delta, accounting for about 64%, and tomato productivity in this region is also the highest in the region But the North is still about 2.4 to 4.9 tons / ha lower than the national average yield

2.5 The situation of tomato research in the world and Vietnam

2.5.1 The situation of tomato research in the world

Breeding technologies are critical for improving crop production in our changing world with an exponentially growing population and in the face of extreme environmental changes New varieties of tomato are created with the aim of: improving yield and quality, resistance to diseases and pests, tolerance to heat and drought stress tolerance, creating early ripe varieties for early season production… The leading research institutes of tomato breeding in the world such as Asian Vegetable Research and Development Center (AVRDC), Indian Agricultural Research Institute (IARI), seedlings companies and universities of the US and Europe, have achieved remarkable success, typically

CLN2026D, CLN2116B, and CLN2123A All 3 varieties have limited growth, are able to withstand many diseases such as bacterial wilt, fungus wilt, virus …(Damtew Abewoy Fentik, 2017)

Pusa Early Dwarf, Pusa Hybrid-1 and Pusa Divya.Each variety has its own distinctive features Pusa Ruby: Indeterminate, early, fruit flattened, medium size processing purpose Pusa Early Dwarf: Plant dwarf, determinate, early maturing,

table and processing purpose PusaHybrid-1: Fruit set at high night temperature *:

Developed using male sterile lines (Damtew Abewoy Fentik, 2017)

characteristics: Determinate habit, pear shaped fruit, suitable for distant markets Also created in America, Sioux is the variety which is suitable for hilly areas (Damtew Abewoy Fentik, 2017)

Efforts were made to breed tomatoes for late blight resistant tomatoes over 50

years ago (resulting in the identification of two resistant genes Ph1 and Ph2

(Gallegly 1960; Peirce 1970; 1971) Accordingly, the Ph1 gene is the dominant gene

originating from the Lycopersicon pimpinellifolium tomato group, which is

specifically resistant to Race 0 (Bonde and Murphy, 1952) Gene Ph1 has been included in fresh edible tomato varieties: New Yorker, and processed tomatoes: Nova

Ph2 is an incomplete dominant gene, also found in the tomato group sour L

pimpinellifolium (Goodwin et al., 1995) The expression level of the Ph2 gene is also influenced by other factors (Turkensteen, 1973; Laterrot, 1975) Gene Ph2 was identified in the West Virginia 63, Legened, Centennial, Caline, Macline, Pieraline, Heline, Fline, Piline, Pieralbo, Heinz 1706, Campbell 28 tomato varieties, Flora Dade, Earlymech and Europeel (Gallegly, 1960; Laterrot, 1994)

Research at the World Vegetable Center (World Vegetable Center - AVRDC) was discovered in the genus L3708, belonging to the

L.pimpinellifolium group, containing a new gene source (Ph3) resistant to mildew (AVRDC, 1994) The Ph-3 gene on chromosome 9 (Chunwongse et al., 2002), was

well resistant to Pi-16 strains, while the Ph-1 and Ph-2 genes did not show resistance

to this strain

Resistance to late blight was also found in wild tomato samples LA1033 (L.hirutum) (Kim and Mutschler, 2000) However, this group of tomatoes is self-incompatible, so it is difficult to cross with cultivated tomato varieties The mildew resistant QTL and genes have been mapped to link on different chromosomes

Resistance to late blight has also been identified in association with a number

of QTLs Based on a hybrid of Solanum lycopersicum x Solanum habrochaites, resistant QTLs were identified on all 12 chromosomes Six QTLs of BC-E (Solanum lycopersicum hybrid population) lb1a, lb2a, lb3, lb4, lb5, lb11b and two QTL of BC-

H (hybrid population with Solanum habrochaites) lb5ab and lb6ab were found QTL

lb4 was mapped on chromosome 4 near TG609 with a distance of 6.9 cM QTL lb5b

is located between TG69a and TG413 on chromosome 5, closest to TG23, and QTL lb11b is mapped on chromosome 11 between CT182 and TG147 (Brouwer et al., 2004)

Although the seed sample of Solanum habrochaites is resistant to late blight,

due to huge genetic differences (green ripe fruit, infinite growth, incompatibility )

with Solanum lycopersicum (planted tomato), it is not used in breeding programs

Kole et al (2006) identified the Ph4 gene on chromosome 2 related to frost resistance

apricot from the seed sample of the S.pimpinellifolium group

2.5.2 The situation of tomato research in Vietnam

Some researchers believe that tomatoes began to appear in our country from the period of the French colonial invasion and occupation Up to now for more than

100 years, tomato plants are increasingly popular and widely used throughout the country The increasing demand for consumption and the increasing demands of the market has raised the urgent issue of choosing and creating a suitable seed set in order to bring into full play the potential of the breed in the ecological conditions of our country Tomato breeding in Vietnam began in the second half of the 20th century and has now achieved very encouraging achievements In our country, the research and breeding of tomatoes is carried out by the Institute, School, Center Including a number of key units such as Vietnam National University of Agriculture, Fruit and Vegetable Research Institute, Field Crop Research Institute, Institute of Agricultural Genetics …

Some of the main achievements that the Center for High-Quality Vegetable Variety Research - Vietnam National University of Agriculture has achieved

- Period 1994-2000: In this period, the emphasis was on creating hot-resistant hybrid tomato varieties By 1997, among the elite groups, an outstanding combination was selected that met the target, and named it HT7 In 2000, the variety HT7 developed mass production of 150 hectares, mainly in off-season (early, late)

in the Northern provinces In September 2000 at the Scientific Conference of the Ministry of Agriculture and Rural Development, HT7 was recognized as a national variety The HT7 variety combines many precious traits: high heat resistance, short term, fast ripening and beautiful red ripe fruit, combining many unique characteristics of the pulp and shell structure to ensure the quality of consumption and quality storage and transport

From 2000 to now, many varieties of pure tomato and F1 hybrid tomatoes selected and created from the Fruit and Vegetable Research Institute, Field Crop Research Institutes, Vietnam Academy of Agriculture have been introduced and distributed development, contributing to the diversification of tomato varieties in

production in the North In particular, it has focused on research and selection and creation of spring-summer tomato varieties, in order to create high-value products

to supply the market and improve people's income

The Field Crop Research Institute has successfully selected and created 2 processed tomato varieties C95, C155 and hybrid tomato varieties VT3 and VT4 Variety C95 had a growth time of 125-130 days, and focused flowering The fruit is elongated, few seeds, yield 40-50 tons / ha in the main season, good quality, suitable for planting in the early season, Autumn-Winter season and Spring-Summer season VT3 tomato variety has the ability to grow, develop strongly, resist pests and diseases, adapt widely, yield over 45 tons / ha VT3 has medium size fruit, flat round shape, thick pulp, green shoulders when ripe, crimson color, rich in powder, Brix level of 4.6%, suitable for fresh food, high yield VT4 variety from 50 to 60 tons /

ha

Fruit and Vegetable Research Institute has successfully selected and created the PT18 processed tomato varieties, the hybrid tomato varieties FM20, FM 29, hybrid number 9 PT18 has elongated fruit, good yield, suitable for both fresh and Processing can be grown in three seasons: Autumn - Winter, Spring - Summer and Winter crops The No 9 hybrid tomato variety exhibits high hybrid dominance, the ability to grow and develop stably in growing seasons, and is resistant to pests and diseases FM29 variety has the average yield is 45-50 tons / ha in the Spring-Summer crop and 55-60 tons / ha in the Winter-Spring crop, suitable for planting on many different soil This group of authors has also studied and successfully created several F1 hybrid combinations (combining mother lines with long stretching stamens susceptible to GA3 and lines with short stamens) for a yield of 49-50 tons / year ha

in some experimental growing areas The technique of producing hybrid seeds with

a new method that did not remove the male line gave the same yield with a normal

hybrid seed production method while the production cost decreased by 35% (Le Thi Thuy, 2012)

Research on starting materials for breeding dominant hybrid tomatoes for processing The author Duong Kim Thoa et al (2012) collected and evaluated a group

of 129 tomato varieties suitable for processing The author has selected a number of varieties with valuable traits, suitable for industrial processing including 14 early ripening, concentrated flowering 55 samples, high yield potential of 72 samples, 20 samples with High soluble dry matter content (brix & gt; 5) and 3 samples that were well tolerant to the tomato yellow leaf curl virus (TYLCV) in which there was a highly combinable D6 line, 3 samples had no stem displacement layer This source

of material is very valuable for the breeding program of tomatoes processed in the Red River Delta conditions

Vietnam Academy of Agriculture pays great attention to hybrid tomato breeding and tomato hybrid seed production technology The F 1 hybrid tomato varieties researched and crossed by the Institute's scientists gave very positive results, many F1 hybrid tomatoes varieties like HT7, HT21, HT42, HT160, HT144 have been developing well in production The HT7 tomato variety is the first hot-tolerant F1 tomato variety that has been researched and successfully bred in Vietnam The variety HT7 has high heat tolerance, short-term, fast ripe fruit, beautiful red ripe, low tree The variety has a content of dissolved dry matter at brix 4.6-4.8, yield 40-56 tons / ha The variety was recognized as a national variety in

2000, with more than 150 hectares of mass production Tomato variety HT21 is a short-term variety, short plants, suitable for planting in the early winter and main winter The variety has round fruit form, high soluble dry matter content, especially high sugar content (brix 5.18%), high yield 45-60 tons / ha HT42 variety is a short-term variety, short plants, good fruiting in unfavorable conditions such as high

temperature, low temperature, low light ., has strong regeneration ability, good resistance to wilt disease bacteria, high yield 45-60 tons / ha (Nguyen Hong Minh

et al, 2011) Especially, HT160 was created in 2000 with short-term advantages, suitable for planting in many seasons The variety has an average fruit weight of 90-100g, slightly oblong fruit shape, beautiful red ripe fruit, thick, firm and smooth flesh, good transportability, sweet taste, and flavor that is favored by consumers High-yielding varieties 50-68 tons / ha are currently being strongly developed outside of mass production (Nguyen Hong Minh et al., 2011)

The group of domestic vegetable seed production and trading enterprises has also contributed significantly to the research and development of the dominant hybrid tomato seed set in Vietnam This is the strongest block, accounting for the largest market share in supplying seeds for production, including companies such as East-West Company, Southern Seed Joint Stock Company, and Seed Joint Stock Company Central government, joint venture companies, companies with 100% foreign capital must be mentioned as Sygenta company, Seminis company, Trang Nong company, Nong Huu company have brought many varieties into production, contributing to the Phu Quoc tomato varieties in our country such as:

Savior tomato variety is well tolerant to yellow leaf curl virus, semi-finite growth, resistant to rain, good heat, hard fruit, beautiful oval shape, convenient for transportation and processing, growth, Strong development, average fruit weight 80-

100 g, average yield 2.5 -3 kg / tree, theoretical yield of 75 tons / ha The variety can grow many crops a year, is F1 hybrid tomato variety being grown with the largest area in the Red River Delta provinces such as Bac Ninh, Bac Giang, Vinh Phuc, Hai Duong… F1 T42 hybrid is selected and created by the Southern Seed Joint Stock Company The variety grows semi-finite, suitable for cool climates in the highlands, can be grown in the dry season and the rainy season, and has good resistance to pests

and diseases Beautiful round fruit shape, good stiffness, does not crack when raining, is popular in the market Each tree has 30-40 fruits, weighing on average 97 -125g Yield 60 -65 tons / ha, seed is widely used in the southern provinces

F1 hybrid tomato variety VL101 produced by Sakata Japan company is exclusively distributed by Hoa Sen Company The variety has high tree characteristics, hard fruit, beautiful color, resistant to bacterial wilt, high yield of 3

kg / tree The variety was developed and favored by tomato farmers in Lam Dong Together with VL101, Anna tomato varieties imported and distributed by Seminis Company are being grown in popularity in Lam Dong, especially in Don Duong district, with about 650 hectares of summer crop in 2010

The authors of the Fruit and Vegetable Research Institute have identified an appropriate genetic source for the breeding of tomatoes resistant to late blight disease

(Phytophthora infestans) in Vietnam By the method of pathogenicity testing with

the source of mycelium, it is collected and isolated from many different regions of the country The results showed that all wild, local and locally grown cultivars had different responses to the isolates of the late blight, but no good resistance was

identified used for breeding In imported cultivars containing Ph1, Ph2, and Ph3 genes, only Ph3 gene samples showed high resistance to different fungal strains The heterozygous form of the Ph3 gene in the F1 combination exhibits moderate

resistance between two parents, reflecting incomplete dominance of this gene This

is the basis for breeding tomatoes resistant to late blight disease in Vietnam (Tran Ngoc Hung et al., 2012)

Development of a molecular marker linked to the Ph3 gene for late blight

resistance in tomatoes has found the SCU602F3R3 directive closely linked to the Ph3 gene, with this result helping breeders to shorten the time in the process of selecting and breeding tomatoes resistant to late blight disease

Tran Ngoc Hung et al (2012) created several tomato hybrid combinations (F1)

with both the late blight resistance (Ph3) and tomato yellow leaf curl virus (Ty1, Ty3) resistance genes, high yield and good quality

Through a survey of 200 tomato varieties, identified 7 strains carrying Ty1

gene, 7 of which had Ty3 gene, of which 2 samples had both Ty1 and tomato yellow

leaf curl virus resistant Ty3 genes

Chapter 3: Materials and methods 3.1 Place and time

- VN-390 and Tre Viet are control varieties

Experiment 2: Pyramiding Ph2 and Ph3 genes for breeding tomato tolerant

to late blight

- The resistance genes Ph2 and Ph3 respectively in the same samples as

LA3151, CLN2037B were used in the study PT18 tomato variety was selected by the Institute of Vegetable and Fruit Research to be susceptible to late blight and used

as a control

3.3 Methods

3.3.1 Evaluating the horticultural characteristics of some tomato lines in early winter season 2020 in Red River Delta