Studying the growth, development capacities and technical measures to increase yields, qualities of some exotic orchid cultivars (cattleya, dendrobium, oncidium) for northern vietnam

<p> 1. Through the results of survey and evaluation on criteria of growth, development and quality of some imported orchid flowers of3 genera of Cattleya , Dendrobium and Oncidium at the nursery and garden production stages, 8 promising orchid cultivars have been chosen, adaptable to ecological conditions of the Northern Delta region: 3 cultivars of the genus Cattleya are Cat1 (Cattleya ploenpit golden delight), Cat3 (Cattleya netrasiri green) and Cat6 (Cattleya haadyai delight); 3 cultivars of genusDendrobium are Den1 (DendrobiumBig white sanan), Den4 (Dendrobiumcharming white) and Den5 (Dendrobiumcherry red), 2 varieties of the genus Oncidium are On1 (OncidiumAloha Iwanaga), On5 (Oncidium(Agnole x Manilatum). The above mentioned cultivars have good characteristics such as good stability, good growth and development, strong tillering, high flowering rate, good flower quality, long lasting flower durability with resistance to pests and diseases harmful insects. These orchi cultivars can meet the requirements of the breedingnew orchid cultivars for production. 2. At the nursery stage,the most appropriate seasonal planting time for 3 orchid cultivars of Cat6, Den5, On1 is in April. The most suitable substrate for Cat6, Den5 is charcoal + volcano foaming slag + seaweed ( 2:2:1 ), for On1is pea gravel + pine bark + seaweed ( 2:2:1 ). Foliar fertilizer Growmore 1(N : P : K = 30:10:10) and substances capable of growth regulators Atonik DD 1.8 ( 0.1 % ) are suitable for the growth and development of all 3 orchid cultivars Den5, On1, 24 increasing survival rate, reducing incidence of soft rotten disease of seedlings in summer of the northern region. 3 . At the stage of garden production,in conditions of summer the Northern delta region, covering by 2 layer reflective mesh consisting of 1 fixed layer and 1 semi-automatic control layer (light intensity 18000-22000 lux ) help orchid cultivar Den5 to grow and develop better, increase flowering and flower quality The most suitable substrate for On1 at this stage is pea gravel+ pine bark + seaweed ( 2:2:1). With Cat6 orchid, using foliar spray Hydrophos 1 time/7 days with the concentration of 0.1 % (1liter infusion for 4m 2 ≈100 plants) has brought about the highest effectiveness. </p>