| Potato is an important food and vegetable crop with high nutritional value.In 2015,the Ministry of Agriculture listed potatoes as the fourth most important food crop in China.The geographical conditions and climatic characteristics of Shanxi Province are in line with the growth conditions of potato.Shanxi Province is a dominant production area for potato planting,but the main potato varieties in Shanxi Province are single and the genetic background is narrow.Enriching potato germplasm resources,accelerating potato breeding process,evaluating genetic diversity among potato provenances,and establishing a perfect identification and evaluation system are the important priorities of potato breeding.To this end,the main potato varieties in Shanxi Province and introduced germplasm resources were used as materials in this study.By investigating the phenotypic traits such as potato plant traits,potato traits,economic traits and quality traits,and combining SRAP molecular markers to analyze the genetic diversity of potato germplasm resources,it provided a research basis for the breeding of potato varieties.The main results are as follows:1.The variation analysis and genetic diversity analysis of 20 main potato varieties in Shanxi Province,the results showed that:The variation coefficients of 20 phenotypic traits ranged from 14.42 to75.87 and the average value was 34.75.The genetic diversity index ranged from 0.56 to 1.95 and the average value was 1.45.The largest coefficient of variation was crown color,and the genetic diversity of quality traits was relatively rich.The cluster analysis results of the main potato varieties in Shanxi Province showed that there were 5 categories in the genetic distance of 18,the first category included 15 varieties,accounting for 75% of the total.It can be seen that the main potato varieties in Shanxi Province are more single and have high similarity.The results of variation analysis and genetic diversity analysis of 108 potato germplasm resources indicated:The genetic diversity index of 7 phenotypic traits ranged from 0.70 to 1.73.The coefficient of variation ranges from 29.39 to 72.95 and the average value was 49.13.The Cluster analysis of the tested potato varieties through phenotypic traits showed: at the genetic distance of 10,108 potato germplasm resources were divided into 4 classes: the class I had 30 varieties,and this class can be divided into 3 sub-categories at the genetic distance of 7;the class II has 17 varieties;the class Ⅲ has 59 varieties,and this class can be divided into 4 Subclass at the genetic distance of 7;the class IV has two varieties.Differences in phenotypic traits were shown between each major category and between subcategories.2.The study established the optimal SRAP-PCR reaction system for potato.Five factors affecting the SRAP-PCR reaction system(primer concentration,Mg2+ concentration,template DNA amount,d NTPs concentration,and Taq DNA polymerase dosage)were optimized by a combination of single factor andorthogonal experiments.3.A total of 24 pairs of primer combinations were screened from 289 pairs of SRAP primer combinations,and 452 bands were amplified.The polymorphic bands contained 405,and the polymorphism ratio accounted for 89.6%.The number of alleles varied from 1.7143 to 2 and the average value was 1.8893.The number of effective alleles ranged from 1.3607 to 1.7526 and the average value was1.5099.The number of genetic diversity ranged from 0.2207 to 0.4103 and the average value was 0.2976.Shannon’s diversity index（I）ranged from 0.3440 to 0.5910 and the average value was 0.4493.The polymorphism information content（PIC）ranged from 0.2505 to 0.4103 and the average value was 0.3312.4.According to the results of primer amplification,the genetic similarity coefficient of 108 potato germplasm resources ranged from 0.2670 to 0.9130 with a range of 0.646.At a genetic similarity coefficient of 0.50,108 potato germplasm resources can be divided into six categories.Among them,there were 65 varieties in class I,which can be divided into 8 sub-categories at a genetic similarity coefficient of0.575;there were 34 varieties with class II,which can be divided into 5 sub-categories at a genetic similarity coefficient of 0.57;there were 2 varieties in class Ⅲ;there were 2 varieties in class IV,3 varieties in class V and 2 varieties in class VI.The classification of the variety had a significant relationship with its source and parent.5.The correlation analysis between the genetic distance matrix of phenotypic traits and the genetic similarity coefficient matrix of SRAP molecular markers showd that r = 0.2278,p = 0.1205,and the correlation was not significant.However,according to the phenotypic traits and the cluster analysis map of SRAP marker analysis,it can be seen that there is a certain similarity between the two studies.By combining morphological markers with molecular markers,the genetic diversity of potato germplasm resources in Shanxi Province can be more accurately and comprehensively evaluated.It provided a research basis for potato germplasm utilization and germplasm innovation,effectively improving the narrow genetic basis of potato in Shanxi Province and speeding up the potato breeding process. |
