Study On Germplasm Evaluation And Growth Regulate Techniques Of Freesia

Freesia is one of the ten cut flowers in the world,some original Freesia species from South Africa have been introduced to carry out breeding work in some European countries as early as the mid 18^th century to 19^th century.In recent decates,many cultivars of Freesia have been introduced from abroad every year and some new cultivars were been breeded in China.Howerver,the corresponding classification preservation and the system management of freesia cultivars are still limited and there are disorderly circulations of some commercial bulbs in the market,the existing Freesia germplasm resources is prone to cultivars confusion phenomenon,coupled with differences in climate and region,Freesia bulb is prone to degradation and germplasm resources can’t be fully utilized,all those problems have seriously hampered the promotion and application of Freesia in China cut flower market.In this study,domestic and imported cultivars of Freesia were used as the plant materals to evaluate the germplasm resources firstly based on the morphological characteristics and RAPD molecular markers,which is helpful to provide a theoretical reference for the full use of Freesia germplasm resources.Further,efforts were made to explore the favorable regulation technology of growth and development of Freesia to provide a scientifical basis for Freesiaproduction.The main results are shown as follows:1.In the study,20 morphological characteristics of 26 cultivarsof Freesia were measured,variability analysis showed that there are abundant phenotypic variation between 26 cultivars of Freesia,especially the flowering traits,the variation coefficient of petal type was maximum,145.9%;The correlation analysis showed that Freesia plant traits,flowering traits and the size of the bulb were interrelated and inseparable.Principal component analysis showed that plant height,leaf width,flower diameter,scapes height,petal color,petal type,stem diameter,initial florescence,flourishing florescence,mother scales weight and diameter,bulblets number can show the main features of Freesia,new cultivars of Freesia classification research can try to start from the analysis of those main characteristics;clustering analysis demonstrated that 26 Freesia cultivars were divided into two categories,characteristics of the first category was small plant type,narrow leaf,small flower,including 9 domestic cultivars and 2 imported cultivars,the second category was tall plant type,very wide and strong leaf,large flower,including 14 imported cultivars and 1 domestic cultivars.We can see that the color and origin are the two main factors of varietal cluster of Freesia.2.Further,35 germplasm materials of Freesia were evaluated by RAPD molecular marker technology.The most polymorphic 15 primers were amplified from 82 random primers,148 bands were obtained,including 96polymorphic bands,accounted for 64.9%of total bands.Thirty-five Freesia materials were divided into two groups,characteristics of the first group was small plant type,narrow leaf,small flower,including all domestic cultivars,the genetic distance was between 0.05 to 0.16,the second group was large flower,strong flower scapes and very wide leaf,including all imported materials and 2 domestic cultivars,the genetic distance was between 0.02 to 0.25,and this group was divided into two groups,the first group contained 12imported cultivars and 1 domestic materials（‘Shangnong Hongtaige’）,the second group contained 10imported cultivar and 1 domestic cultivar（‘Shangnong Chenghuang’）.3.Freesia was planted in pots with 11 kinds of compound substrates,garden soil were used as control group.The results showed that the combination of peat and coir dust and different inorganic substrate was best for vegetative growth of Freesia,the combination of garden soil and coir dust and sand had a best effect on the ornamental traits,followed by the effect of the combination of garden soil and peat and sand and the commercial substrate.Taken all results consideration,50%peat and 30%coir dust and 20%vermiculite was the best treatment for the vegetative growth of Freesia,20%pure garden soil and 60%coir dust and 20%sand was the best treatment for the ornamental effect of Freesia.It was worth mentioning that the effect of pure garden soil was worse than other groups,so the common garden soil can not meet its growth requirements,and should be improved in the future.4.The effect of bio-fertilizer（Seaweed fertilizer）and long-term-release fertilizer（Osmocote）on plant growth and development in freesia was studied.The results showed that when the dilution ratio is 400×Seaweed fertilizer nutrient solution,the total plant fresh weight,total dry weight,soluble sugar content,floret number,scape strength,bulb diameter and the number was greater than that of the other groups,and the difference between the dilution ratio of 400×and 800×was not significant;when the concentration dilution ratio was 2000×,the plant height of Freesia was much more than the other groups,except the 400 treatment,all treatment groups delayed flower time;In slow-release fertilizer treatment,the suitable concentration of standard and high potassium fertilizer all can promote the growth of Freesia,the best concentration of standard fertilizer was 5 g/L,the optimum concentration of high potassium was 7 g/L,and plant height,leaf width,scape height,scape number,scape strength,chlorophyll content was higher than the other group,and earlier than the control group 10 days of flowering with 7 g/L potassium fertilizer,high concentrations of standard fertilizer inhibited the growth of freesia.Generally,400 times of Seaweed fertilizer nutrient solution liquid,5 g/L of Osmocote standard fertilizer and7 g/L of high potassium fertilizer had a positive impact on growth and development of Freesia,can guide the future practice.5.Potted freesia plants were treated with the solutions of salicylic acid in different concentrations by bulb immersing,leaf spraying and combining the both ways to study the regulation effect of SA on the growth and development of Freesia,the freesia without SA application was used as control.The results showed that SA application at low concentration（150mg/L）promoted the growth and bulb development of Freesia,while SA in high concentration（450 mg/L and 600）inhibited the growth and flowering of Freesia,and the leaves were easy to be hurt under the treatment at high concentration by immersing bulb;the dwarfing effect was not significant by leaf spraying.In summary,the comprehensive effect at 300 mg/L SA immersing bulb+450.0 mg/L SA spraying leaf was best for the growth and flowering of Freesia.In addition,the experiment was carried out on Freesia by bulb immersing and leaf spraying of different concentrations of Me JA,the results showed that the treatment of bulb immersing promoted the plant height,but leaf spraying showed a opposite effect on plant height.The effect of two treatment methods on flower diameter,flower number,scape diameter and strength of Freesia were not significant.In comparison,leaf spraying with 10mg/L Me JA showed a best complicated effect,including the effect on dwarfing,the highest values of the flower number,flowering stage,and total soluble protein content and a week earlier blossoming by compared to control.