Study On Flowering Phenological Variation Of Walnut Hybrid Population And Extracting Method Of Total RNA From Walnut

Dichogamy is one of the important biological characteristics of walnut. Walnut in northern region is susceptible to late spring frost injury for early blooming, resulting in a partial freeze of walnut flowers. Therefore, study on phenological characteristics of walnut florescenc has important significance to the production and breeding. The filial generation was selected from Shandong Agricultural University forestry experimental station, and then the flowering phenology and flowering phenology variation were studied in three consecutive years. In order to further research regulation principle of Flowering Genes in walut , clone floral gene from early-fruiting walnut floral induction way, induced early flower and shorten the juvenile phase , this study attempt to extraction total RNA with different methods , Finally , the improved CTAB extraction total RNA Successfully , this study was constructed into a flower-related gene cloning system, which laid down the basis for further cloning flower-related genes.The main results were as follows:1.Based on the three consecutive years investigation and the results of statistical analysis about the walnut floral phenophase, it showed little different about the date of the flowering period of population, but the concentrated emergence of flowering phenology phenomenon of the entire population appeared quite different. First flowering stage of pistillate of walnut usually appeared in early April, which varied from 2 to 6 days among individuals in different years; but on the whole population, blooming emergence concentrated in the middle and last ten days of April. As for full flowering stage of pistillate, it varied from 1 to 5 days at individual in different years, and the blooming emergence concentrated in the middle and last ten days of April as well as early May. Especially the full flowering stage of pistillate in 2008 was more influenced by climatic factors except duration time. Terminal flowering stage of pistillate generally concentrated in the first and middle ten days, which varied from 2 to 8 days at individual in different years and later about one week compared with full flowering stage. Duration time lasted10 to 20 days, especially 15 days appeared most. Through the two years investigation about first flowering stage of staminate, it appeared a little more concentrated for the whole population and male flower phenophase also more stable.2.The variance analysis were adopted to estimate the difference among individuals and among different years of first flowering stage of pistillate,full flowering stage of pistillate,terminal flowering stage of pistillate and duration time; most of the variation which were significant differences except duration time among individuals. Therefore the fore three phenophase could be selected effectively.Phenotypic variance of each female flower phase was big and varied from 35.477 to 38.129, and phenotype variation coefficient had little difference but duration time that varied from 47.6% to 56.1%, which indicated there were relatively wide selection range and great potential gain in progeny populations. Genetic variation coefficient of all traits was high which indicated rich genetic variation existed and having more selection potential. The broad-sense heritability were relatively big and varied 82.7% to 99.4%, which indicated florescence characters were more influenced by genetic than by environment and could be selected effectively and accurately by the method of selecting single plant at earlier generations. Under 5% intensity of selection with in the whole population, the relative genetic progress of all traits were between 114.8%, 96.7%, 97.5% and 26.6%, respectively, which mean more selection potential and relatively better expected gain would be made at earlier generations .With the cluster analysis and the significant test of class centre to the walnut offspring population of female flower, the entire 121 individuals walnut offspring were divided into 20 categories and the first flowering stage of pistillate were directly selected. As a result 8 individuals were selected out of which the first flowering stage of female flower of the individual was relatively later.3.This research indicated that improved CTAB method is a fast, convenient and appropriate way for RNA extraction in walnut. The results showed clear bands and indicated that the RNA was of high purity and good quality and was suitable for RT-PCR and the construction of cDNA library. It is believed that the CTAB method is especially useful for the RNA extraction of plant materials which have plentiful polysaccharide, hydroxybenzene, pigment and other secondary metabolites. This research constructed a good system for cloning of the floral related genes.