Researching On Hybridization Between Different Populations Of Pinellia Ternata Linn.(Araceae) For Breeding

20 populations of P. ternata that were collected from different areas in China were cultivated in pots and used in hybridizations between different populations for breeding. In this thesis, questions were focused on as follows. 1) How to select populations as parental materials used for hybridizations? To develop a convenient and useful method for parent selection, morphological characteristics, life cycle,inflorescence characteristics, cytological characteristics and yield traits were respectively determined in each population. The markers of parent selection were determined based on the correlation analysis between various characteristics and yield traits in each population. 2) How to obtain active pollens used for hybridizations? TTC staining and pollen germination in vitro were used to determine pollen viability. Based on pollen viability test, the most suitable period of pollen collections and environmental conditions of pollen conservation were determined. 3) What period is suitable to artificial pollination? Two kinds of method were used to test stigma viability. Based on stigma viability test, the optical period of artificial pollination was determined. 4) If there is hybridization compatibility in various parent combinations?Based on observations on seed development of each hybridization combination, the relationships between compatibility and chromosome number were analyzed. For these questions, researching results were listed as follows:1. Markers used in parental material selections for hybridization of P. ternataThrough observations of the various morphological characteristics in each P. ternata population,markers that could be used for parent selection were identified. 1) Parent selection can perform on the basis of difference of morphological characteristics, namely leaf shape and bulbil type. 2) Selection could carry out based on differences of agronomic traits that include the longevity of growth period, leaf areas and bulbil location near. 3) Selection can execute based on the differences of floral organs, such as the length of male inflorescence, pollen number, and the length of female inflorescence.2. Detection of pollen viability and determination of pollen collection periodPollen germination in vitro and chemical staining were used to detect pollen viability. Results showed that the most appropriate staining method was TTC staining. TTC staining in the detection of pollenviability is simple in operation, economic in time consuming and higher resolution. Pollen germination in vitro can be replaced by TTC staining that contributed to optimize and simplify the P. ternata pollen vigor testing part and provide the convenience for breeding work in cultivation process of P. ternata.3. Detection of stigma viability and Determination of artificial pollination periodResults showed that the changes of stigma viability that were determined by benzidine-hydrogen peroxide method and artificial pollination method were consistent. Benzidine-hydrogen peroxide method can be used to crossbreeding work of P. ternata to further determine the optimum period of pollination. The advantages of Benzidine-hydrogen peroxide method were simple operation, short time consuming and clear results, which can provide a convenient method to crossbreeding work.4. Seed development in various hybridization combinationsThe pollen and stigma viability of P. ternata population changed at different time, the results showed that the period of the strongest pollen viability was the time of scattering powder 2 or 3 days at 9:00 to10:00 in the morning. The period of stigma viability was the strongest before flowering 1 day and flowering 1 day at 9:00 to 10:00 in the morning. There were different hybridization combinations in our study, the results showed that there was a huge difference in the reciprocal-crossing seed setting rates of other parent combinations, such as the reciprocal-crossing seed setting rates of Hezhang* peach leaf shape and Pingliang peach leaf shape and the reciprocal-crossing seed setting rates of Hezhang* single bulbil type and Xiangyang single bulbil type. Namely, there were visible differences in the hybridization compatibility in parent combinations.5. Relationship between parental chromosome numbers and seed development in hybridizationResults showed that the inconsistent numbers of parental chromosome hadn’t an obvious effect on hybridization when the numbers of parental chromosome both were the aneuploid numbers. However,hybridization was failed when the number of one of parental chromosome was the aneuploid number, and the reason may be that the sample size was too small. Namely, there wasn’t obvious relationship between the compatibility and chromosome number when parental chromosome numbers were aneuploid numbers no matter what number. Visiblely, the hybridization compatibility in parent combinations wasn’t affected by the inconsistent numbers of parental chromosome.