Optimization Research On Aspesis Breeding Seedling And Efficient Cultivation Technique Of Bletilla Striata

Bletilla striata Rchb.F.,a perennial medicinal herb of the genus Bletilla in Orchidaceae,also known as Bletilla striata,Lianhe grass and kamkerng.The dried pseudobulb of Bletilla striata can be used as medicine,which has high medicinal value.According to the records of‘Shennong herbal classic’,‘Benjing’and‘National collection of Chinese herbal medicines’,Bletilla striata has the effects of bloodletting detumescence and muscle regeneration,hemostasis and lung tonifying.The germination rate of Bletilla striata seeds under natural conditions is extremely low.Although the seeds can germinate under semi-open temperature and humidity control,they have high requirements for facilities and equipment.In addition,Bletilla striata seeds have no endosperm.When the seeds are directly used for seedling emergence,it is easy to die because there is no nutritional supply;Bletilla striata seedlings can also be propagated by ramets,but ramets have low propagation rate,slow propagation rate and uneven seedling quality.Since there are tens of thousands of seeds in each pod of Bletilla striata,sterile rapid propagation technology is used to promote seed germination,and then the organs and seedlings formed after germination are used as explants for induction and differentiation to produce Bletilla striata seedlings in batches.In view of this,this study established a set of rapid propagation system of B.albicans by optimizing the medium formula.The transplanting technology and cultivation management method of Bletilla striata were optimized by studying the changes of growth and yield benefit under different cultivation and site conditions.The main results are as follows:1.The rapid propagation system of aseptic germination,bulb induction and strong seedling culture of Bletilla striata is established by optimizing the culture technology.The optimal medium for seed germination of Bletilla striata is 1/2 MS+NAA 0.1 mg/L+GA₃ 0.1 mg/L+20 g/L white sugar;The optimal medium for bulb induction and seedling strengthening is 1/2ms+NAA 0.6 mg/L+6-BA 0.8 mg/L+PP₃₃₃ 0.5 mg/L+Banana Puree 30 g/L+sugar30 g/L.The’two-stage’rapid propagation system of Bletilla striata aseptic seedlings established in this study can obtain high-quality and robust Bletilla striata aseptic seedlings in90 days,which is suitable for industrial breeding of Bletilla striata.2.The survival rate of aseptic seedling transplanting of Bletilla striata was significantly related to the type of Bletilla striata seedling.The larger the bulb,the higher the survival rate;Changes in transplanting time,humidity,temperature and other environmental conditions will affect the survival rate of Bletilla striata seedlings.The suitable time for transplanting Bletilla striata is from April to September;Altitude gradient and soil type had certain effects on the transplanted seedlings of Bletilla striata,but the difference was not significant.The survival rates of paddy soil and yellow soil were slightly higher than those of humus soil and river sand（4:1）,which might be related to the water retention and air permeability of soil.3.The experiment of foliar fertilization at Bletilla striata and transplanting seedling stage found that the effect of foliar fertilization with MS was better than that of potassium dihydrogen phosphate,and the fertilization effect with 1/2MS and 1/4MS interval of 6 days and 10 days was better,which may be related to that transplanting seedlings need absorb a large amount of nutrients to promote growth in the early stage.4.There were significant differences in economic yield among different planting densities.Among them,the economic yield of 30cm×35cm row spacing was the highest,the dry yield per mu was about 120kg,followed by 25 cm×35cm treatment,the dry yield per mu was about111kg,and the yield of 35cm×35cm and 40cm×35cm treatment was the lowest.Reasonable planting density can give full play to the advantages of comprehensive yield increase of single plant and population,which is an important technical measure to improve economic yield.Therefore,it is appropriate to plant about 80,000 plants per hectare with 30cm×35 cm row spacing in the production of Bletilla striata.5.Fertilization can promote bletilla yield,but it needs the combined application of N,P and K fertilizers.Reasonable fertilization treatment can increase the yield by 3%～27%.The effects of N,P and K Fertilizers on yield increase were different.The order of promoting effect on bletilla yield increase was K>P>N.Fertilization had little effect on bletilla yield,reproductive coefficient and seedling emergence rate,and did not reach a significant level among treatments.6.The correlation between altitude and soil types and Bletillae rust incidence rate and damage index is relatively large.At altitude of 200-480m or 800m,or sandy soil and loam soil can reduce the incidence rate and harm index of Bletillae rust.In the early stage of bletilla rust,the application of anti-rust potion（effective content 20%,concentration 1500 g/hm²）can effectively control the occurrence of rust.