Summary of agricultural doctoral thesis: Studying the growth, development capacities and technical measures to increase yields, qualities of some exotic orchid cultivars (cattleya, dendrobium, oncidium) for Northern Vietnam

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The purpose of this research subject is to study the growth, development of some exotic hybrid orchid genera of Cattleya, Dendrobium, Oncidium in order to select new promising hybrid orchid cultivars, consistent with the Northern Delta region and the nearby region with similar ecological conditions.

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Nội dung Text: Summary of agricultural doctoral thesis: Studying the growth, development capacities and technical measures to increase yields, qualities of some exotic orchid cultivars (cattleya, dendrobium, oncidium) for Northern Vietnam

MINISTRY OF EDUCATION MINISTRY OF AGRICULTURE AND TRAINING AND RURAL DEVELOPMENT VIETNAM ACADEMY OF AGRICULTURAL SCIENCES HOANG XUAN LAM STUDYING THE GROWTH, DEVELOPMENT CAPACITIES AND TECHNICAL MEASURES TO INCREASE YIELDS, QUALITIES OF SOME EXOTIC ORCHID CULTIVARS (CATTLEYA, DENDROBIUM, ONCIDIUM) FOR NORTHERN VIETNAM Branch of study: Crop science Code : 62 62 01 10 SUMMARY OF AGRICULTURAL DOCTORAL THESIS HANOI - 2014
Project completed at: VIETNAM ACADEMY OF AGRICULTURAL SCIENCES Scientific supervisors: 1. Ass. Prof .Dr. Nguyen Thi Kim Ly 2. Prof. Dr. Nguyen Xuan Linh Critic 1: Critic 2: Critic 3: The thesis is defended at Council for Thesis Assessment at University/ Institutional level, held at: Vietnam Academy of Agricultural Sciences At hours, day month year This thesis can be referred to at: - Vietnam National Labrary - The Libray of Vietnam Academy of Agricultural Sciences
1 INTRODUCTION 1. Urgency of research topic Of all popularly planted types of flowers, orchids are known as a flower not only beautiful, fragrant, multi – colorful, but also are of high economic value. So far, mankinds have learned on more than 750 orchid branches with 35000 wild orchids species and 75000 orchid cultivars as a result of selection and breeding [33]. In Vietnam, there are about 1003 species of orchids available [ 33 ]. These are very abundant plant resources to serve the creatation and breeding of new varieties of orchids. However, most of these orchids can only be exploited and cultivated in natural conditions, technical measures have not yet been applied, so their yields and qualities are not high that can not meet the requirements of consumers. Whereas the exotic orchids have their advantages as having good growth and healthy development, high yields , good quality of flowers: big flowers, beautiful colors, various diversified, durable and long -lasting flowers and that their flower blooming time can be controlled for the occasions of Holidays or Lunar New Year Celebration, that has brought about high economic efficiency to growers. Cattleya, Dendrobium, Oncidium are pretty orchids species popularly esteemed by the markets. It is attractive to consumers with diversified colors, beguiling aroma and especially, commercial producers are attracted by the durability of flowers. However, the actual production of these orchids in Vietnam still faces many difficulties. Lan Cattleya, Dendrobium , Oncidium orchids are very suitable the climate in Southern areas as of its all - year-round warm weather, great sun radiation and long appropriate sunlight for plant to grow and develop, whereas the climatic condition in the North is not favorable due to high summer temperatures (33 - 380C), high humidity and high sunlight intensity that causes a negative impact to the growth of the plants, making the plants susceptible to leaf blight, high percentage to rotten disease prevalence. In Winter, the temperatures is too low, weak sunlight intensity, short sunlight during the days are also not favorable for plant growth , development and giving flowers. On the other hand, as for lack of good seeds, technical inconsistency and inappropriate caring process ... the production cuold not bring about high efficiency, quantity and quality of orchids still can not meet consumer requirements, while the demand for the above mentioned orchids is very high. In order to overcome this limitation, enabling plant orchids in general and Cattleya, Dendrobium and Oncidium orchids in particular to
2 develop to be effective, the research subject " Studying the growth, development and technical measures to increase productivity, quality of exotic orchid varieties (Cattleya , Dendrobium , Oncidium ) for Northern Vietnam . " 2. The purpose and requirements of the subject 2.1. Purpose - The purpose of this research subject is to study the growth, development of some exotic hybrid orchid genera of Cattleya, Dendrobium, Oncidium in order to select new promising hybrid orchid cultivars, consistent with the Northern Delta region and the nearby region with similar ecological conditions. - To determine the impact of growing conditions and technical factors to the growth, development, flowering of some exotic hybrid orchid genera as Cattleya, Dendrobium, Oncidium and to propose appropriate technical measures, applying effectively to production that contribute to the development of growing orchids in the Northern Delta. 2.2. Requirements of the research subject: - To evaluate the adaptability of exotic orchids belonging to 3 branches of Catlleya, Dendrobium and Oncidium (survival, growth and development capabilities) in the period of nursery and in production gardens in order to select some new promising orchid cultivars adaptable to ecological conditions of the Northern Delta region. - To study the effect of growing conditions (substrate, fertilizers, shading system, flowering control) to the growth and development of selected hybrid orchids in order to identify appropriate technical measures that help reaching high yield, high quality of flowers for these orchids. 3. Scientific and practical significances: 3.1. Scientific significance - The results of the study subjects have provided the scientific data on basical criteria for an orchid to reach high yield, good quality as well as the influence of growing conditions (temperature, light, substrate, fertilizer, ...) to the growth, development and the formation of flowers and flower quality of the Cattleya orchid, Dendrobium, Oncidium in Northern Delta conditions. - The study results are also references of great value for teaching, research and production of orchid plants in general as well as Cattleya, Dendrobium, Oncidium in particular.
3 3.2. Practical significance - Having introduced to production 8 exortic hybrid orchids belonging to 3 branches of Cattleya, Dendrobium, Oncidium adapted to the ecological conditions of the northern delta region with good stability, growth and development that meet the requirements of selecting new orchid cultivars for production. - Have proposed farming techniques to increase the capabilities for the growth, development and the proportion of bearing flowers for these newly selected orchid cultivars. These technical measures are of high feasibility, high application capability to mass production that bring about highly practical effectiveness for growers. 3.3 The Novelty of the thesis - Having fully and systematically studied the morphological characteristics , growth and development for an orchid to gain high yield and quality. On that basis, 3 hybrid orchid cultivars of Cattleya, Dendrobium , Oncidium with good prospects for growth, development, good flowering in the condition of Winter - Spring season in the Northern Delta region, have been selected for the production of hybrid orchids. - Having studied systematically the growing conditions and technical measures for eachcrop season for 3 orchid genera of Cattleya orchid, Dendrobium, Oncidium, in order to increase survival rate of seedling and to reduce the incidence of soft rotten disease in nursery stage in hot and humid summer climate condition. At the same time, it helped to increase the rate of flowering of the plants as well as flower quality blooming in cold winter conditions of the Northern Delta region . 4. The structure of the thesis The main contents of the thesis are presented in 139 pages (excluding references and appendices). Introduction: 4 pages; Chapter 1: Overview document: 40 pages, Chapter 2: Materials, research content and methodology: 17 pages; Chapter 3: Research Results and Discussion: 76 pages; Conclusion and proposals: 2 pages. The dissertation consists of 37 tables, 19 form, 50 Vietnamese documents, 72 documents in English. The appendix includes photos of selected orchids in the experiments, statistical analysis results and experimental data processing and contents related to the thesis.
4 Chapter 1 OVERVIEW 1.1 General Overview of the orchid Cattleya , Dendrobium , Oncidium Cattleya (Cattleya orchids) includes about 65,000 primitive species and numerous outvarietal and intervarietal crossed species. They are native to tropical America, mostly in the mountains with altitude from 600 - 1800 m [46]. Dendrobium (Hoang Thao orchid) is the largest genus in orchid family, consisting of over 1,600 species whose distribution stretches from Korea, Japan, Indonesia ... to Australia. In Vietnam, over 200 species of orchid Dendrobium has been recorded [ 94 ]. Oncidium (dancing lady) consists of about 400-600 species originating from the America and subtropical regions. They can be found from Florida to the Bahamas, Caribbean Islands and southern Mexico, Central and South America to Argentina [122]. By studying botanical characteristics and for external requirements for Cattleyas, Dendrobium, Oncidium, it is shown that climatic condition of Vietnam can absolutely be suitable for the culture of this species, particularly in the provinces of the Southern region. However, because of the cold weather in the northern provinces, the plants are less developed and grown. To develop this orchid in production, it is necessary to pay special attention to the uses of substrates, fertilizers, growth regulators, flowering stimulants and flowering control measures on the occasions of Tet and Holidays. 1.2 The status on production and consumption of Cattleya, Dendrobium, Oncidium orchids in the world and in Vietnam: Export markets of orchids on the world are ever-expandin. European Union (EU), North America and Japan are still biggist areas to consume most cut- orchids, although China is also becoming an important market. Only 25 countries of the EU on average have spent 13.7 billion USD/year (CBI, 2007) for consumer cut- orchids, mainly Dendrobium and Oncidium, accounting for over 50% of total orchid consumption. Of which, Germany topped with the expendicture of about 3 billion euros per year. The folowing 5 countries with high demand are the UK (2.82 billion ), France (1.85 billions), Italy (1.62 billions), Spain (0.99 billions) and the Netherlands (0.89 billion ) [ 118 ]. Japanese consumer demand by 5.4 million/year
5 on cut orchid, U.S: $ 5.5 billion [119]. It can be said that orchid production has brought about very highly profits for developed and developing countries. Besides, Cattleya, Dendrobium, Oncidium account up for the bulk of total production and consumption of orchids in the world. This proves that these flowers bring high economic efficiency to growers and preferred by consumers. Cattleya, Dendrobium, Oncidium are common orchids genera which bring high economic efficiency for the orchid production branches of orchid growing countries over the world. In recent years, thanks to the expansion of production and development of these orchids, significant economic benefits have been brought about to countries such as Thailand, Taiwan, Singapore, China ... With similar climatic conditions to these countries and experienced growers, the Cattleya, Dendrobium, Oncidium orchid genera can be grown and fully developed in Vietnam . Orchid growing area in Vietnam is t at modes level, only accounting for 10 % of the flowers growing areas [23]. Production of orchids in Vietnam concentrates in 2 main directions : - Production of newly bred or selected orchid species or or imported ones in industrial scales (industrial orchids). - Exploiting and cultivating native orchids species (wild orchids). Thus, the production, trading of orchids in Vietnam so far still remains in the form of potentiality. Meanwhile, the competitiveness on the world market is very huge. The trading activities and export in recent years are only at launching stage that leads to a promising future for development of these flowers basing on the existing favorable conditions for the development of orchid growing branch. 1.3 Status of research on Cattleya, Dendrobium, Oncidium orchids in the world and in Vietnam: 1.3.1 Status of research on Cattleya, Dendrobium, Oncidium orchids in the world For many years, due to high economic and aesthetic values of orchid plants, that developed countries in the world have used traditional techniques and modern methods for breeding and selecting flowers in general and for orchids in particular and have achieved very satisfactory results, especially on some industrial orchids as Dancing lady (Oncidium), Hoang Thao (Dendrobium), Cat (Cattleya) and some other orchids and these have brought about big financial resources for orchids producing branches in countries as Netherlands, China, Taiwan, Thailand ...
6 The above results show that the world has had a lot of research work on orchid plants, in general and on the genera of Cattleyas, Dendrobium and Oncidium, in particular. The study focused on a number of areas such as plant breeding and seed multiplication, technical planting measures and measures for pests and diseases preventions, ... 1.3.2 Status of research on Cattleya, Dendrobium, Oncidium orchids in Vietnam In Vietnam, there have been many studies on collectioconservation the genetic resources of native orchids and exotic cultivars as well as evaluation and selection of promising orchid varieties for production and concentrate to study technical measures on substrates, fertilizers, flowering control techniques, pest prevention ... The research results that have been applied in production have initially brought about positive effectiveness in the development of orchid cultivation in Vietnam. However, new researches have just been carried out on some objects and technical process for planting, taking adequate care of the orchids, especially Cattleya, Dendrobium and Oncidium, have not been completed. From the results of the study, it is shown that Cattleya, Dendrobium and Oncidium can fully grow and develop well in Vietnam, especially in the southern region due to the warm climate all the year round. In the northern delta regions, due to cold winter temperature, the plants can not grow and develop well, and very often there are virtually no flowering in winter time. To develop and grow the orchid genus Cattleya, Dendrobium, Oncidium in condition of Northern Delta region, it is necessary to deeply study the growth, development and flowering characteristics of these cultivars. At the same time, research on technical planting measures to increase survival rate, to reduce the incidence of soft rotten disease of seedlings in summer time and increase flowering rate, flower quality of mature plants in winter time for the introduced hybrid orchids belonging to the 3 above - mentioned orchid genera. Chapter 2 RESEARCH MATERIALS, CONTENT AND METHODOLOGY 2.1 Research Materials 2.1.1 Varieties:
7 - 5 Oncidium orchid cultivars, imported from Thailand, as seedlings after the stage of tissue culture, with height: 6-8 cm, number of leaves: 3-4 leaves/plant, number of roots: 5-7 roots/plant and one Oncidium cultivar which is widely planted in production as the controls (cntrl). 5 Dendrobium orchid cultivars, imported from Thailand, as seedling, after the stage of tissue culture with height: 6-8 cm, number of leaves: 2-3 leaves / plant, number of roots: 4-6 roots/plant and one Dendrobium cultivar which is widely planted outside in production is used as the controls (cntrl). - 6 one leaf Cattleya orchid cultivars imported from Thailand were used as seedling after the stage of tissue culture with height: 5-7 cm, number of leaves: 2-3 leaves/plant, number of roots: 3-5 roots/plant and 1 cattleyas which is widely planted in production outside was used as the control (cntrl). 2.1.2 Substrates: The experiments included 5 types of substrates formula of differen mixing ratios. - Coal (charcoal), pine barks, light stones, volcano foaming slag, Seaweed 2.1.3. Leaf Foliars: - Including 5 types of fertilizers: Growmore, Hidrophos, Multi K fertilizers, Striving buffalo, Milo-3 Distribution 2.1.4. Substances capable of regulating the growth(growth regulator): - DD 1.8 Atonik, ProGibb 10 SP, Dekamon 22.43L 2.1.5. Substance capable of stimulating flowering: - Asco Gold, RB, AT preparations 2.1.6. Other materials: - Slow release root fertilizer N: P: K = 14:14:14, wires, Compax bulbs 75W and 100W, incandescent bulbs 75W and 100W, clamps ruler, tape-measure, electronic balance, light intensity meter, moisture meter ... 2.2 Research contents: 2.2.1 To evaluate the growth, development capacities and select some exotic hybrid orchid cultivars belonging to 3 orchid genera of Cattleya, Dendrobium, Oncidium adaptable to the North Delta area 2..2.2 Study some technical measures in the nursery stage for some selected exortic hybrid orchid cultivars belonging to 3 orchid genera of Cattleya, Dendrobium, Oncidium. 2.2.3 Study some technical measures at the stage of production garden for some selected exortic hybrid orchid cultivars belonging to 3 orchid genera of Cattleya, Dendrobium, Oncidium.
8 2.2.4 Study some measures to control flowering time for some selected exortic hybrid orchid cultivars belonging to 3 orchid genera of Cattleya, Dendrobium, Oncidium. 2.3 Research Methodology and experimental design * Methods of experimental design - The experiments were designed in a randomized complete block design (RCBD) [33] with three replicates. At nursery stage, each treatment consisted of 150 plants; at the garden production stage, each treatments consisted of 75 plants. The observation, subscription and measurment on the growth and development criteria of the plants were conducted on30 plants/ treatment. 2.3.1 Methods to evaluate the growth, development capacities and select some exotic hybrid orchid cultivars belonging to 3 orchid genera of Cattleya, Dendrobium, Oncidium.. - Experiment 1: Study the growth at the nursery stage of the exotic hybrid orchid cultivars belonging to 3 orchid genera of Cattleya, Dendrobium, Oncidium.. - Experiment 2: Study the growth, development and flowering capacity at the garden production stage of the exotic hybrid orchid cultivars belonging to 3 orchid genera of Cattleya, Dendrobium, Oncidium. 2.3.2 Experiments on technical measures at the nursery stage - Experiment 3: Effect of the seasonal planting time to the growth of the seedlings at nursery stage. - Experiment 4: Effect of the type of substrates to the growth of seedlings at the nursery stage. - Experiment 5: Effect of some foliar fertilizer to the growth of the seedlings at nursery stage. - Experiment 6: Effect of some growth regulators to the growth of the seedlings at nursery stage. 2.3.3 The experiments on technical measures in the garden production stage for the exotic hybrid orchid cultivars belonging to 3 orchid genera of Cattleya, Dendrobium, Oncidium. - Experiment 7: Effects of shading system to the growth and development of selected orchid cultivar Den5. - Experiment 8: Effect of different types of substrates to the growth and development of selected orchid cultivar On1. - Experiment 9: Effect of some foliar fertilizers to the growth and development of selected orchid cultivar Cat6.
9 2.3.4 Experimental study on some technical measures to control flowering time for the selected exotic hybrid orchid cultivars of 3 orchid genera of Cattleya, Dendrobium, Oncidium. - Experiment 10: To study the effect of types of additional lightings to flowering and flower quality of orchid cultivars Den5 and On1. - Experiment 11: To study the effect of additional lighting time to flowering of orchid cultivars Den5 and On1. - Experiment 12: To study the effect of additional lighting time combining with plastic coverage to the ability of flowering to orchid cultivars Den5 and On1 - Experiment 13: To study the effect of flowering stimulants to flowering capacity of selected cultivar Cat6. 2.4 The observation criteria 2.5 The conditions and equipment applied in experiments 2.6 Data processing The study results are processed by biostatistics methods by computer software Excel and IRRISTAT software version 5.0. 2.7 Locations and time of trials - Experiments 1, 2, 3, 4, 5, 6, 7, 10, 11, 12 were carried out in the conditions of Rhichel House at Van Giang Biological Experimental Camp, Agricultural Genetics Institute. - Experiments 8, 9, 13 were implemented in the conditions of seedling nursery nethouse in Phu Thuong Team - Management Board of Ba Dinh Square, Hanoi. - Trial time: 2006-2012. Chapter 3 RESULTS AND DISCUSSION 3.1 Assessment of growth and development and selection of some exotic hybrid orchid cultivars of 3 orchid genera Cattleya , Dendrobium, Oncidium. 3.1.1 Some growth characteristics of exotic hybrid orchids at nursery stage At the nursery stage , Oncidium and Dendrobium orchid have relatively high survival rate (48.7 to 72.2 %), the Cattleya orchid has lower survival rate (39.5 to 52.8 %). However, in the hot, humid summer conditions of the Northern Delta
10 region, soft rotten disease prevalence is relatively high, thus it has significantly reduced the proportion of seedlings ready for planting. Therefore, in the nursery stage, applying technical measures (substrates, fertilizers, growth stimulants ...) to reduce the incidence of soft rotten disease in seedlings is a critical necessity for production . Table 3.1 . Growth characteristics of exotic hybrid orchids at nursery stage (November, 2006 - Van Giang , Hung Yen, 8 -month-old seedlings) Criteria Soft No of No of Survival Plant Leaf Leaf rotten stems/ leaves rate hight length width disease plant /plant (cm) (%) (cm) (cm) severity (stems) (leaves) Cultivars (%) Cat1 51.3 16.2 4.3 4.3 10.2 3.3 7.3 Cat2 43.3 13.7 3.6 3.6 8.6 3.0 18.5 Cat3 50.7 15.4 4.2 4.2 9.4 3.2 9.0 Cat4 39.5 14.1 3.0 3.0 8.1 3.0 36.3 Cat5 48.3 13.3 3.8 3.8 8.7 3.4 3.0 Cat6 52.8 16.5 4.4 4.4 10.6 3.5 8.7 Cat7(cntrl) 50.3 13.3 3.7 3.7 8.5 3.0 9.5 CV% 2.4 6.8 6.8 4.1 7.2 LSD0,05 0.6 0.5 0.5 0.7 0.4 Den1 61.5 21.1 3.4 10.5 12.4 2.2 4.7 Den2 48.7 22.3 2.1 9.3 10.7 2.3 16.5 Den3 52.1 20.5 2.7 9.2 11.5 2.6 2.3 Den4 63.7 22.8 2.6 8.1 12.2 2.4 7.0 Den5 65.6 22.6 3.9 10.4 13.6 2.4 8.0 Den6(cntrl) 56.3 20.3 2.0 8.9 10.3 2.1 9.6 CV% 6.8 8.9 5.0 6.0 11.1 LSD0,05 2.6 0.4 0.8 1.3 0.5 On1 72.2 14.1 3.2 4.6 11.5 1.2 9.3 On2 68.6 16.8 3.7 4.8 14.1 1.5 22.5 On3 53.3 16.3 3.0 4.2 14.3 2.1 17.3 On4 59.1 17.5 3.3 4.7 13.7 1.9 8.7 On5 67.5 16.6 3.8 5.4 12.8 1.9 9.3 On6(cntrl) 65.0 12.0 3.0 4.4 9.5 1.1 9.7 CV% 6.2 8.3 7.7 6.6 13.5 LSD0,05 1.7 0.5 0.6 1.5 0.4
11 Seedlings at the nursery stage of the study, orchids grow well, have high tillering ability to facilitate growth and development in the future. This proves that the imported seedlings at the nursery stage perfectly adapted to the ecological conditions of the Northern Delta area . 3.1.2 Some growth characteristics of exotic hybrid orchid at garden production stage Table 3.2. Growth characteristics of exotic hybrid orchids at garden production stage (December, 2009 - Van Giang, Hung Yen) Criteria Number Number of Plant Leaf Leaf Diameter of stems / leaves height length width (cm) plant /plant (cm) (cm) (cm) (stems) (leaves) Cultivars Cat1 35.5 2.3 10.5 10.5 20.5 5.0 Cat2 30.3 1.8 7.1 7.1 17.1 3.7 Cat3 34.7 2.3 10.6 10.6 20.5 4.9 Cat4 33.7 2.1 9.6 9.6 19.3 4.5 Cat5 31.7 1.9 8.3 8.3 18.2 3.8 Cat6 36.1 2.5 11.7 11.7 21.5 5.5 Cat7 32.5 1.8 8.6 8.6 20.5 5.1 CV% 5.1 11.8 6.7 4.2 8.2 9.6 LSD0,05 3.0 0.4 1.1 0.7 2.8 0.8 Den1 39.1 1.7 5.9 28.4 15.4 3.9 Den2 36.4 1.8 5.2 27.0 15.6 4.1 Den3 37.2 1.9 5.3 27.2 1.2 4.5 Den4 42.5 1.9 6.1 29.8 15.0 4.4 Den5 42.8 1.9 6.2 29.3 16.8 4.0 Den6 33.6 1.4 4.3 26.0 14.7 4.0 CV% 5.3 10.3 7.3 5.1 6.6 8.3 LSD0,05 3.7 0.3 0.7 2.5 1.8 0.6 On1 36.2 3.0 4.2 10.6 28.7 2.4 On2 40.2 3.5 5.3 15.9 31.2 3.0 On3 38.9 4.5 6.2 18.8 30.1 4.3 On4 39.6 4.2 5.5 16.3 31.5 4.1 On5 39.6 4.2 5.6 16.6 31.7 4.1 On6 32.3 2.7 4.4 12.5 22.2 2.2 CV% 5.0 6.5 6.8 7.6 5.9 7.8 LSD0,05 3.3 0.4 0.6 2.1 3.1 0.5 The evaluation on the growth of exotic orchids at mature stage showed that cultivars Cat6, On1 and Den5 have the best growth indicators.
12 3.1.3 Studying flowering ability of exotic orchids Table 3.3. Ability of flowering of researched orchids (December, 2009 - Van Giang, Hung Yen) Criteria No of effective Flowering No of flowers / No of buds / flowers / plant ratio (%) plant (flowers) plant ( buds) Cultivar ( flowers ) Cat1 36.3 1.4 3.2 3.0 Cat2 20.6 1.2 2.7 2.3 Cat3 38.1 1.5 3.4 3.2 Cat4 33.8 1.2 2.4 2.1 Cat5 17.5 1.4 2.9 2.6 Cat6 56.7 1.4 3.3 3.2 Cat7 21.0 1.2 2.4 2.1 CV% 9.5 6.6 6.6 LSD0.05 0.2 0.3 0.3 Den1 72.9 1.3 10.7 10.1 Den2 61.4 1.1 7.2 6.6 Den3 56.0 1.1 8.6 7.1 Den4 72.3 1.2 9.4 9.0 Den5 76.2 1.4 11.8 11.3 Den6 70.7 1.1 5.4 5.0 CV% 9.4 4.1 4.3 LSD0.05 0.2 0.6 0.6 On1 56.7 3.5 117.1 101.1 On2 51.3 2.3 78.7 60.8 On3 43.7 5.6 52.4 44.2 On4 52.0 2.9 84.6 75.6 On5 54.3 3.4 109.3 97.3 On6 51.3 2.0 83.7 72.2 CV% 7.6 7.8 8.5 LSD0.05 0.4 12.2 11.4 Thus, all orchid cultivars in the orchid group of the research are well capable of flowering. Depending on the cultivars, number of flowers differs. The number of effective flowers in Cattleya was from 2.1 to 3.2 flowers/plant , Dendrobium from 5 to 11.3 flowers/plant, Oncidium: from 44.2 to 101.1 flowers/plant.
13 3.1.4 Research on quality characteristics of the imported orchid cultivars Table 3.4 . Some quality characteristics of the orchid flower in the study (December, 2009 - Van Giang , Hung Yen ) Criteria Length of Flower Natural Color Flower diamet Durabili Fragrance stem er (cm) ty (days) Cultivars (cm) Cat1 14.5 13.0 17.7 Orange light fragrant Cat2 10.7 12.4 14.7 Whitr, purple lip light fragrant Lemon gold, Cat3 12.0 13.2 17.7 Very fragrant purple lip Cat4 8.3 9.6 15.3 Light pink light fragrance Cat5 9.6 8.4 13.3 Light violet No smell Yellow, dark Cat6 14.8 13.7 18.7 Very fragrant purple Cat7 8.4 8.2 9.0 White Purple No smell CV% 3.1 3.0 2.7 LSD0.05 0.6 0.6 0.7 Den1 31.1 8.0 41.7 Whitish Non- aromatic Den2 26.3 8.4 37.3 Bright pink Non- aromatic Den3 27.9 8.3 41.0 Whitish purple Non- aromatic Den4 30.7 8.2 43.7 White, red lip Non- aromatic Den5 32.4 8.3 54.7 Red Non- aromatic Den6 22.0 6.7 34.7 Whitish Non- aromatic CV% 6.7 3.9 5.5 LSD0.05 3.4 0.6 4.1 On1 32.2 3.63 36.3 Dark yellow Non- aromatic On2 50.0 3.25 31.3 Dark yellow Non- aromatic Spotted On3 42.0 4.57 24.3 Very fragrant Chocolate On4 47.0 5.12 33.3 Spotted white fragrant On5 48.0 5.16 33.7 Fasciated yellow Very fragrant On6 27.0 3.03 27.3 Dark yellow Non- aromatic CV% 4.8 4.7 6.8 LSD0.05 3.5 0.4 3.7 From the results of the studies on the quality of flowers, it showed that, of all Cattleya orchids in the research, Cat6 has the best characteristics of flower quality, such as flower length (14.8 cm), large flower diameter (13, 7 cm), flower long-lasting durability (18.7 days) and fragrant flowers. In the varietal study on Dendrobium and Oncidium varieties, cultivars On1 and Den5 have the best criteria
14 on flower quality. This is the basis for the selection of promising varieties for production . Thus, the testing results showed that the majority of the imported Cattleya orchid, Dendrobium and Oncidium are of good growth and development, strong tillering ability and uniformity. The studied varieties proved their suitability for the climatic conditions of the northern delta region, have good flowering, various and beautiful flower colors, high natural durability, representing the color characteristic of the varieties. These varieties are well resistant to pests and diseases, harmful insects. 3.2 Research on technical measures for the exotic hybrid orchid cultivars belonging to 3 selected orchid genera of Cattleya, Dendrobium, Oncidium at the nursery stage 3.2.1 Influence of the seasonal growing time to the growth of selected orchids at nursery stage Table 3:11 . Influence of the seasonal growing time to the growth of selected orchids at nursery stage (November, 2006 - Van Giang , Hung Yen) Plant No of No of Survival Cultivar Treatment hight stem/plant leaves/plant rate (%) (cm) (stems) (leaves) CT1 52.7 13.3 3.5 3.5 CT2 74.6 16.5 4.4 4.4 CT3 66.3 14.1 3.8 3.8 Cat6 CT4 70.2 15.2 4.1 4.1 CV% 2.0 4.9 4.9 LSD0,05 0.6 0.4 0.4 CT1 65.7 17.9 2.4 8.0 CT2 84.0 22.6 3.9 10.4 CT3 73.5 19.1 3.0 8.2 Den5 CT4 79.3 20.7 3.3 9.6 CV% 1.5 6.8 3.2 LSD0,05 0.6 0.4 0.6 CT1 72.3 13.5 2.7 4.1 CT2 83.0 15.6 3.4 4.6 CT3 78.7 13.8 3.0 4.2 On1 CT4 83.3 14.1 3.2 4.6 CV% 1.8 6.3 4.4 LSD0,05 0.5 0.4 0.4 Note: CT1: March CT3: May CT3: April CT4: June
15 Tỷ lệ sống (%) 93,7 91,0 89,3 89,0 90,0 88,0 86,5 84,3 83,8 81,0 78,2 77,6 74,5 70,0 CT1 CT2 CT3 CT4 CT1 CT2 CT3 CT4 CT1 CT2 CT3 CT4 Cat6 Den5 On1 Figure 3.4. The influences of substrates to survival rate and growth capacity of selected orchid cultivars at nursery stage Thus, in the nursery stage, the best substrates for Orchid cultivar On1 is: light stone + pine bark + seaweed (ratio 2:2:1). With this substrate, the survival rate of On1 is 91%, the plant is fat, healthy, well-developed, the growth indicators are higher than other treatments. 3.2.3 The influences of foliar fertilizers on the growth of selected orchids at nursery stage Chiều cao cây (cm) CT1 CT2 CT3 CT4 30,0 27,2 25,6 26,0 24,3 25,0 20,3 18,5 19,7 18,9 18,4 20,0 17,2 17,3 16,6 15,0 10,0 5,0 0,0 Cat6 Den5 On1 Figure 3.5. Effect of foliar fertilizers to the height of the selected orchid plants at the nursery stage The results of the study showed that foliar fertilizer Growmore 1 (30:10:10) concentration of 0.1% periodically sprayed 1time/ week/helped selected orchids Cat6, Den5, On1 to grow and develop best at nursery stage
16 Tỷ lệ sống (%) CT1 CT2 CT3 CT4 96,7 97,3 94,7 93,3 93,5 93,5 91,7 91,1 90,0 86,3 84,3 83,6 81,2 70,0 Cat6 Den5 On1 Figure 3.6. Effect of growth regulators to the survival rate of the selected orchids at nursery stage Thus, in the nursery stage, to increase the growth potential for the selected orchids Cat6, Den5 and On1, spraying Atonik with dosage of 0.1%, 7 days/time helped seedlings to grow well, increase survival rate, reduce soft rotten disease incidence, increase plant height and tillering caapacity of seedlings. 3.3 Research on technical measures for the selected orchids in the garden production stage 3.3.1 Effect of shading measures to the growth, development and quality of orchid flower Cultivar Den5 3.3.1.2 Effect of shading measures to the ability of flowering of the orchid Den5 So, with orchid Den5, shading with 2 layer, reflective mesh: 1 fixed layer, one semi-automatic control layer (light intensity 18000-22000 lux) is most suitable for summer conditions in the North Delta area that helps the plant to grow and develop well, increase the ability to achieve higher flowering to 90.7 %, increase flower length, flower diameter and increase the durability of the flowers. This result is quite right to the affirmation of Nguyen Thi Kim Ly (2009), [26] when she asserted that the suitable intensity of light for Dendrobium orchid was from 15000- 30000 lux.
17 Table 3.20. Effect of shading measures to flowering capacity of Den5 orchid (July, 2010 - Van Giang, Hung Yen) Criteria Average No of Number of No of Effective flowering flowers / plant buds / plant flowers / plant ratio (%) (flowers) (buds) (flowers) Treatment CT 1 (Cntrl) 86.4 1.3 11.9 9.2 CT 2 86.3 1.4 12,4 11.3 CT 3 81.3 1.4 12,7 11.6 CT 4 90.7 1.5 13.5 12.8 CV% 5.9 3.4 2.4 LSD0,05 0.2 0.8 0.5 Note: CT1 : No cover (cntrl) CT2: Cover by 1 layer, fixed reflective mesh (22.000 – 28.000 lux) CT3: Cover by 2layer, fixed reflective mesh (15.000 – 18.000 lux) CT4: Cover by 2 layer reflective mesh: 1 fixed layer, one layer of semi-automatic control (18.000 - 22.000 lux) 3.3.2 The influence of substrates to the growth, development and quality of orchid cultivar On1. 3.3.2.2 Influence of substrate to the flowering ability of orchid cultivar On1 Table 3:23. The influence of substrates to the flowering ability of the orchid cultivar On1 (December, 2010 - Phu Thuong, Tay Ho, Ha Noi) Criteria Number of Flowering Average No of No of Effective buds / ability flower stems / flowers / plant plant (%) plant (stem) (flowers) Treatment (buds) CT1 56.8 3.5 118.3 103.0 CT2 60.7 4.1 126.9 112.3 CT3 76.3 4.7 163.5 146.7 CT4 70.7 4.2 137.4 116.8 CT5 (Cntrl) 50.0 3.2 130.2 114.5 CV% 9.9 10.0 11.3 LSD0,05 0.7 24.7 24.4 Thus, the treatments using different types of substrate have significant impact to the quality criteria of flowers such as length of flower stem, flower diameter, flower durability. The mixture of substrate of pea gravel + tree bark + seaweed with proportion 2:2:1 is best suited for the growth, development and
18 quality enhancement for On1 orchid flower. The research results are consistent with the assertion of Tran Van Bao (2001) [1] and Viet Chuong (2001) [5] when they comfirmed that using tree bark and seaweed (firn) as substrate for growing orchids was very good. However, with the conditions in the North Delta area, for On1 orchid cultivar, it is necessary to add pea gravel. This is a very important component to mix as substrate for Oncidium orchids. 3.3.3 Influence of foliar fertilizer to the growth, development and flower quality of orchid cultivar Cat6. 3.3.3.2 Influence of foliar fertilizers on the flowering ability of orchid cultivar Cat6 Table 3:26. Effect of some foliar fertilizers to flowering ability of orchid Cat6 (December, 2010 - Phu Thuong, Tay Ho, Ha Noi) Criteria Number of Flowering Average No of No of Effective buds / ability flower stems / flowers / plant Treatment plant (%) plant (stem) (flowers) (buds) CT1 (Cntrl) 56.7 1.4 3.3 3.2 CT2 58.6 1.5 3.4 3.2 CT3 57.1 1.5 3.5 3.4 CT4 67.3 1.5 3.5 3.4 CT5 69.5 1.5 3.5 3.5 CT6 73.2 1.6 3.7 3.7 CV% 6.3 5.8 5.6 LSD0.05 0.2 0.4 0.3 Thus, it can be seen that foliar fertilizers affected the ability of flowering of orchids Cat6. Fertilizer Hydrophos (CT6) with dose of 0.1%, spraying 1 time/week would help orchid cultivar Cat6 strongly bear flowers, more stems (1.6 stems/ plant) and the high rate of effective flowers blooming (73.2%). This result is quite right to the assertation of Nguyen Cong Nghiep (2000) [29] when said that when applying fertilizers to Cattleyas, in addition to maintaining the growth and development, it was also aiming to control the flowering of these orchids. The study results also found out that Hydrophos fertilizer (Treatment 6) is of high of P and K which gave best performance on Cat6 orchid. This is also consistent with findings of Pham Thi Lien (2010) [20] while studying the effects of foliar fertilizers to flowering and flower quality of Dendrobium. 3.4 Research some techniques to control of flowering for selected orchid cultivars of Cattleya, Dendrobium, Oncidium 3.4.1 Influence of the types of additional lighting lamps to the flowering capabilities and flower quality of orchid cultivars Den5 and On1.