At the same time of introduction, Wang Dajun also devoted himself to the research of flower breeding. In 1950s, on the basis of introducing more than 600 chrysanthemum varieties, Wang Dajun chose lily, a big chrysanthemum variety with more than 3000 flowers per kloc-0/000. In 1960s, Wang Dajun participated in the national scientific research project and was responsible for establishing the Shanghai Chrysanthemum Center Park. In order to build this national chrysanthemum base, he collected more than 6,000 chrysanthemums extensively, selected more than 500 excellent varieties of/kloc-0 from them, and bred 60 excellent varieties of chrysanthemums and 50 varieties of Xiao Ju. In the process of collecting chrysanthemum varieties, Wang Dajun found that the classification and naming of horticultural flowers in China are quite confusing, and foreign bodies with the same name and different names are very common, especially in the classification of chrysanthemums. This is not conducive to flower research, nor to production and promotion. Based on the simplicity and practicability of practical operation, according to the international flower classification theory, based on morphological characteristics and strains, he formulated the three-level classification of chrysanthemum "flower type-color-variety number", which has a guiding role in flower production.
Wang Dajun attaches great importance to the application of hybrid breeding technology in flower variety breeding. In the early 1960s, he took Petunia as the breeding object and cultivated Petunia with red and white petals (hybrid) and Petunia with red, white and purple petals. In 1970s, the interspecific hybridization of Hibiscus was carried out, and the hybrid of Hibiscus rubra and Hibiscus was successfully obtained, which can significantly prolong the viewing period. In order to prevent the excellent strains from degenerating, Wang Dajun selected several excellent strains. Among them, Corydalis grandiflora has the largest flower diameter of11cm; Impatiens is a hybrid variety with a single pure double flower at the top of the branch; Celosia grandiflora, with a large flower head, can reach 30 cm horizontally, and the colors are rare colors such as reddish, brown yellow and brown red; The double-petal Scutellaria barbata strain has strong double petals and rich colors, including rare colors such as emerald, brown red, meat red and sprinkled gold. All the above strains are suitable for the climate in Shanghai and grow and bloom well. In 1980s, in order to meet the demand of bedding plant in high temperature season, Wang Dajun successfully introduced a number of perennial plants with flowering period from June to August, such as polyploid HEMEROCALLIS, Iris Louisana and various dwarf hibiscus, which added variety color to urban greening.
Wang Dajun attaches great importance to the accumulation, exploration and research of cultivation techniques. While introducing and cultivating flowers, we also put more energy into the training of skilled workers and cadres. Textbooks for junior and intermediate technicians of flowers have been compiled, including a series of textbooks and papers such as "Flower Seed Collection and Cultivation in the Open Field" and "Introduction of Herbaceous Ornamental Plants and Climate". A large number of skilled workers and cadres have been trained.
In the practice of flower cultivation, Wang Dajun deeply felt that the improvement and development of flower breeding level must adopt and develop new technologies and materials. In the early 1980s, China's reform and opening up had just started, and there were few exchanges between horticulture and foreign countries. In addition, the protection and blockade of foreign patents in flower gardening make it very difficult to obtain excellent germplasm resources. In order to obtain excellent seedlings, Wang Dajun has applied a whole set of techniques of germination, transplanting and seedling formation. He used constant temperature artificial light to raise seedlings, germinated Petri dishes with non-toxic medium, and transplanted seedlings with new gardening non-toxic medium (vermiculite, peat, coconut shell), which greatly improved the germination rate and seedling rate.
In the mid-1980s, most greenhouse plants in China were planted in glass sheds, and the ventilation and heating system was not perfect. At the suggestion of Wang Dajun, Shanghai Botanical Garden introduced advanced glass fiber reinforced plastic multi-span greenhouse, which created conditions for a large number of indoor and outdoor flowers and foliage plants. At that time, the park introduced and collected more than a thousand indoor ornamental plants from home and abroad.
In the mid-1980s, as soon as tissue culture technology appeared in the field of production and application, Wang Dajun was keenly aware of its broad application prospects. Responsible for the preparation of the tissue culture building of Shanghai Botanical Garden, with a production capacity of 500,000 seedlings. He made great efforts in tissue culture technology, trained a group of technicians, and propagated tissue culture seedlings of horticultural plants such as lily and daylily, which were exported to the Netherlands and the United States. Therefore, Shanghai Botanical Garden has become one of the earliest units in China to produce and export flower tissue culture seedlings on a large scale.
Botanical garden is an important base for protecting plant diversity. One of the important means for botanical gardens to promote plant protection is the exchange of germplasm resources and information. In the early 1980s, Wang Dajun founded the Seed Exchange Room of Shanghai Botanical Garden, personally led a team to collect wild plant seeds, and exchanged germplasm resources, protection technology and information with botanical gardens at home and abroad.
As for the collection of wild plant seeds, Wang Dajun mainly concentrates on the wild plants in the Yangtze River valley. He is quite original in compiling the exchange catalogue. In addition to the botanical name, he also recorded the collection time, place, altitude, ecological environment, collectors and other data, reflecting the elements of plant ecology and introduction and domestication to meet the needs of botanists and experts in introduction and domestication. This exchange catalogue compiled by him has been appreciated by the international botanical garden community and adopted by many botanical gardens. The maximum number of plant species included in the catalogue is 1000. Since the publication of the exchange catalogue, it has attracted the attention of botanical gardens all over the world. Countries have sent letters asking for the establishment of exchange relations. By the end of 1980s, more than 40 countries and regions had established stable exchange relations with them, including more than 300 botanical gardens and botanical gardens. This work has reached the level of similar botanical gardens in the world and improved the visibility of Shanghai Botanical Garden in the international botanical garden community. 65438-0996 British Deputy Prime Minister heseltine asked for the seed exchange catalogue of Shanghai Botanical Garden through the British Foreign Office. During his visit to Shanghai, he made a special trip to visit the Shanghai Botanical Garden, and in his letter, he spoke highly of the seed exchange catalogue of the Shanghai Botanical Garden.
In promoting international exchanges, Wang Dajun also participated in the international flower fairs in Montreal and Amsterdam, the Netherlands, and the construction of China Garden in the flower fairs, and was appointed as a member of the selection committee of the international flower fairs. Wang Dajun also gave lectures abroad for many times, and was known as a chrysanthemum expert in Montreal.
1In March, 1995, royal horticultural society awarded Wang Dajun Vicky the Memorial Medal in recognition of his outstanding contribution in the field of international communication and gardening.
Wang Dajun has a strong sense of professionalism and responsibility. Academically, he attaches great importance to the combination of theory and practice, emphasizes practical operation, and has strong sensitivity and understanding ability to new concepts and technologies. He devoted himself to gardening in China. Because it has always emphasized technical management, it was once regarded as a typical "white road" and was impacted. However, Wang Dajun's love for the motherland and persistent pursuit of landscape architecture are unshakable. During the period of decentralization, he didn't complain, but became one with the workers. He devoted all his energy to the improvement of horticultural cultivation techniques and patiently taught them to workers.
After retiring, Wang Dajun still pays attention to the development of botanical gardens. With rich experience, he guided seed exchange and plant protection, and kept Shanghai Botanical Garden at an advanced level in the world botanical gardens. He enthusiastically instructed young horticultural and flower researchers to go deep into the production line and solve and answer new problems in breeding in time. He also often makes suggestions for the development of Shanghai Botanical Garden. Wang Dajun has always been proud that China is the "mother of gardens" in the world. He has long wanted to introduce the ancient history of flower cultivation and breeding in China and its brilliant achievements in gardening. But I'm busy at work and have no time to take care of it. After retirement, I finally have a chance to realize this long-cherished wish. After decades of data collection, he is writing the history of ancient ornamental plants cultivation in China. Although Wang Dajun is 76 years old, he still pays great attention to the development of gardening in China and continues to contribute to the improvement of gardening in China.