| Sorbus pohuashanensis (Hance) Hedl.is a tree species native to north China with high ornamental and ecological values, the species is distributed in high mountains in north China. Based on a comprehensive investigation and collection of seed resources, we studied the variability of and correlation among mophological traits of seeds, germination rate between and withing provenances of 14 natural and 1 planted provenances.The growth performance of 3 year old seedlings were assessed for 6 provenances, key factors affecting survival rate of cutting propagation were studied. Survival rate of grafts on different rootstocks were also measured. Observations were conducted to study the phenology of the species in order to facitlitate artificial cultivation of S. pohuashanensis. This study is intended to lay a theoretical basis and reference foundation for domestication of the species, for breeding new varieties for ornamental uses, and for conservation and utilization of genetic resoruces of S. pohuashanensis. The main results are as follows:1.Higj genetic diversity in mophological traits of seed and germination rate were found within rovenances of S. pohuashanensis. Variance analysis showed that the difference of seed length, seed width, thousand-seeds weight, germination rate, and other seed mophological traits were significant. The needed duration of low temperature stratification of seeds of different provenances was significantly positively correlated with elevation, positively correlated with latitude; and negatively correlated with mean annual temperature, a highly positive correlation was found between germination rate and thousand-seeds weight, seed width.2.Seedling growth of SDLS provenance was significantly higher than the other 5 provenances, SDTS slightly below the SDLS, significantly higher than other four provenances, no significant differences of growth were showed among SXP, HBB and HBW provenances. HBT rovenance was the worst in height, significantly lower than other 5 Provenances. Superior seedlings at 3 years of age were selected using the standard deviation method,14.44% of the seedlings of SDLS provenance were selected,,followed by 6.67% of SDTS,and 2.22% of HBW.Abundant variation was found in fruit color, autumn leaf color in the natural resources by an investigation of S. pohuashanensis in Tuoliang mountain, Hebei province. Leaf colors can be divided into red and yellow, accounting for 70.59% and 29.41% respectively; Fruit colors can be divided into red, pink and yellow, accounting for 52.94%,35.29% and 11.76%. respectively.3.The results indicated that the cutting from mother trees at three years of age with application of 2200 mg·g-1 NAA were the best treatment for rooting(rooting rate of 89.66%) and for root growth for cutting propagation.4. Different rootstocks had highly significant effects on the survival rate of grafting, the highest survival rate was found in the rootstock of S. pohuashanensis, the survival rate was 62%;and followed by the rootstock of Begonia evansiana, the survival rate was 52%.5.The height growth of S. pohuashanensis mainly occurs in June, July and August, ground diameter mainly in September, October and November. The seedlings of S. pohuashanensis began to bloom at age 3,flower buds were found in approximately 10% of the plants, mainly on the top.Young seedlings of S. pohuashanensis(1-2 years) have difficulties in adapting to high temperature and dry environmental conditions, and they need shading protection in summer, while 3 years' seedlings need not shade protection. |
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