The Genetic Diversity Analysis And Mutation Breeding Of Pteroceltis Tatarinowii

Pteroceltis tatarinowii Maxim. is one kind of deciduous trees that originated in China. It can be used to produce fiber or calcareous soil and now it has been included in the state of protection. Pteroceltis tatarinowii Maxim. has been found in 19 provinces of China, such as Gansu, Guizhou, Anhui, Jiangsu and Shandong, Hubei and Hunan Province. Due to destruction of human activity, a large number of wild Pteroceltis tatarinowii has disappeared.At the same time, artificial cultivation of Pteroceltis has lead to low diversity of Pteroceltis tatarinowii species. We collecte 8 populations of Pteroceltis tatarinowii in this experiment in order to analyze these germplasm resources by AFLP(amplified fragment length polymorphis), the results will provide a theoretical basis for the protection and use of Pteroceltis tatarinowii. There was few reports about the breeding of Pteroceltis tatarinowii in China during the past years, and the study of Pteroceltis tatarinowii breeding is still at the primary stage. In this study, we focus on the mutagenic effect of ethyl methyl sulfonate(EMS)on Pteroceltis tatarinowii seeds with different concentrations and different mutation methods.We hope to get excellent germplasm variations according to this study. The standards to evaluate germplasm variations including mortality rate caused by EMS,leaf color viation and mutation screening of Pteroceltis tatarinowii seedlings. The results will lay the foundation for further Pteroceltis tatarinowii mutagenesis. The main results obtained are as follows.1. The AFLP experiment was carried out to analyze the 28 samples of 8 Pteroceltis tatarinowii populations, after a screening of PAGE, 6 pairs of primers polymorphic were screened. The signal intensity, with uniform distribution. 6 pairs of primers produced a total of203 bands, of which 191 bands were polymorphic, the rate of proportion(PPB) is 94.08%, the average of each pair is 31.8. The polymorphism of E35M83, E40M55, E43M54 and E41M64 were all over 90%, and the combination of E35M83 and E86M85 was 98.28%, the lowest was75%. That Pteroceltis tatarinowii have rich genetic variation at the species level.2. Analysis of Pteroceltis tatarinowii populations genetic diversity shows that the percentage of polymorphic bands(ppb) have bigger differences at the population level.“Lingyan” was the highest with 53.69%, “Chang Ping” was the lowest with only 14.78%.Nei’s gene diversity index(H) was between 0.0610 and 0.1774; population of the Shannoninformation index(I) was between 0.0886 and 0.2703. It dedicated that genetic diversity of Pteroceltis tatarinowii at both of the species level and population level is relatively high. The genetic diversity of Pteroceltis tatarinowii will be smaller and smaller according to decreasing population size of Pteroceltis tatarinowii and artificial propagation. The protection of Pteroceltis tatarinowii population should be strengthened.3. In the experiment of breeding mutation of Pteroceltis tatarinowii, three kinds of materials was treated with EMS: ungerminated seeds, germinated seeds and Pteroceltis tatarinowii seedlings. Compared with the control group, the mortality rate of the seeds without germination was similar to that of the control group, the germination and seedling treatment were significantly lower, and the mortality rate increased with the increase of the concentration of EMS treatment. Analysis on leaf color mutation rate showed that when EMS concentration was between 1.2% to 1.5%, the leaf color mutation rate is the highest, and the seed germination is disposed below the growth point. So the best time point for Pteroceltis tatarinowii leaf color variation by EMS mutagenesis was 48 hours after growing.4. After treated by EMS, we found that the leaf color, height, thickness of Pteroceltis tatarinowii seedlings varied. Compared to the control group, the morphological effects of Pteroceltis tatarinowii seedlings treated by EMS is mainly manifested in the leaf color and height. Along with the change of EMS concentration and treatment time, Pteroceltis tatarinowii seedlings appear different types of variation: yellow, variegated and whitening.But with the growth of plants, some of variations gradually become normal, green or dead,especially before the end of August, and the variation gradually tends to be stable from September to the fallen leaves. After EMS treatment, there are a total of 28 tree leaf color mutant plants, with the variation of plant growth, last remaining 3 tree leaf color mutant plants, including 2 tree leaves variant plants and 1 tree spot leaf variation plant, the stable rate is only 10.71%.5. The EMS chemical mutation variant plants of Pteroceltis tatarinowii varies in seedling height, diameter and control seedlings in the experimental group. The survey found that in mid May, the difference is inconspicuous, after gradually obvious, to August, has been able to clearly observe the difference between the two groups. Yellow leaves and variegated mutants in height, diameter and number of branches was significantly lower than the control group. By September, the control group were higher than that of leaves and leaf spot of 0.774 m and 0.602 m mutants. Leaf color mutants grow slowly significantly, related to photosynthesis with yellow, variegated effect.