Construction And Verification Of High-Starch Core Collection In Potato

The national potato germplasm bank collects and preserves1910potato germplasm resources, ahuge amount of resources have brought many difficulties for the conservation, evaluation, research andutilization of germplasm. Nearly210varieties were bred in the past60years, the great achievementswere made, however, long-standing emphasis has been placed on high-yield breeding with diseaseresistance, the quality breeding was ignored, the special varieties, especially processed varieties areextremely scarce, and they can not meet the development of the processing industry and the exportneeds, it has a very important theoretical and practical significance for the construction of thehigh-starch core collection, evaluation research, analysis of high-starch core collection of geneticdiversity distribution genetic relationships, the further collection of high starch resources, classification,preservation, excellent germplasm mining and breeding for high-starch.In this study, the construction method comparison optimization of phenotypic core collection of thehigh-starch potato and core collection construction were made, the evaluation of the phenotypic corecollection of high-starch potatoes and perfection were made, which were based on the construction ofmolecular data and high-starch potatoes core collection,phenotypic data, molecular data and constructedphenotype of phenotype plus molecular data, comparative study and evaluation of the molecular andcomplex core collection, the study on high-starch potato core collection has been carried out in theconstruction of a high-starch potato core collection, the main conclusions are as follows:1.1910potato germplasm resources from national potato test–tube plantlets bank were asexperimental materials, starch content is higher than17%as a standard,154high-starch potatogermplasm materials were screened, starch content of1%difference is as a standard, the hierarchicalgrouping method was used, all germplasm materials were divided into four groups, they were based on55morphological trait data,the role and effect of the sampling ratio method in four groups and6overallsample size in construction of high-starch potato core collection were compared.The results showedthat the diversity scaling method in the group enabled sampling the number of the each group orproportion of each group tend to balance and maintaining the original collection variability, when theoverall sample size was25%,the core genetic diversity index of diversity proportion method reached tothe maximum, the phenotypic reserved proportion reached more than95%, when the overall sample sizeincreased to over30%, the proportion of phenotypic retention was close to100%, the core germplasmdiversity index decreased quickly, the25%of the overall sample size was more appropriate, the corecollection including40germplasms with high starch were constructed, according to the obtainedoptimization scheme and phenotypic level.2. The40high-starch phenotypic core collections of potato were constructed, phenotype geneticdiversity index, the proportion of phenotypic retention, extreme coincidence rate, mean coincidence rateand standard deviation coincidence rate were used to evaluate the genetic representation. The resultsshowed that the phenotypic index of the overall numberof high-starch potato core germplasm and foursub-groups genetic diversity were:1.013、0.901、0.819、0.922�'�1.100、0.960、0.911and0.977,theirvalues were higher than the corresponding values of the original collection, the average phenotype retention ratio of49quality traits of core collection was91.8%.the6quantitative trait coincidence rate,the mean coincidence and standard deviation coincidence rate reached to82%or more, the phenotypiccore collection of high-starch potato were better than the original collection in variability abundancedegree and mean degree, which represent the genetic diversity of the original collection, In accordancewith the evaluation results of the phenotypic representation,6germplasms with containing missingtraits were added, the phenotypic core collections were added to46materials.3. The19pairs SSR primer were used to analyze the primary core collection of62high-starchpotato,119DNA bands were amplified, polymorphic bands were116, the proportion of polymorphicbands were97.5%, the6.1polymorphic bands were amplified from average each primer pair, on thisbasis, the eight kinds were obtained by analyzing (20%,30%,40%,50%,60%,70%,80%and90%),the sample size cluster was compressed to pre-selected core germplasms, it could be seen on theretained proportion, for allelic variation reserving the proportion or phenotype retention ratio, there wasbig increase-range before80%the sample size with the increase in the sample size, for genetic diversityindex, Shannon-weaver diversity index and phenotype genetic diversity index reached to a peak value,which was the sample size of80%, by the sample size cluster-compression of80%, the49molecularcore collections with high-starch were obtained from62primary core collection.4．The62primary core collections with high-starch were used as the test materials, the clusteringcompression of the phenotype SSR molecular data and completely random sample to build twopre-selected core collection（M3and M4）, Nei’s the allele diversity index, observed number of alleles,effective number of alleles, Nei’s genetic diversity index and Shannon’s information index were used toanalyse the phenotype core collection (M1), the molecular core collection (M2) and the two pre-selectedcore collection, the order and the sum of each parameter were made, the results showed that M1and M3were tied for the first in the sort of genetic diversity, M2was the second, M4was the third,phenotypicdata, molecular marker data and phenotypic data plus molecular marker data were used to clustercompression,which could achieve good results, the phenotypic data revealed plant differences in theambient conditions, molecular marker data revealed differences in the level of genomic DNA of plants,it should take into account interaction effect of the environment and gene in building core collection, thephenotypic data plus molecular marker data were selected to cluster compression and achieved49accessions, which were as the final core collection of high-starch potato germplasm resources, and theirrepresentative evaluations were made, the orders of genetic diversity index of the core collection, thephenotypic variance and the coefficient of variation were0.4652,0.0663,0.6253, the orders of primarycore collection were0.4611,0.0652,0.5689, the core collection phenotype retention ratio was98.78%,the above index of the core collection were higher than the values of the primary core collection, thepolymorphic loci percentage of the molecular core collection and the average number of alleles wereequal to the corresponding value of the primary core collection, average effective number of alleles,Nei’s genetic diversity index, Shannon’s information index and Nei’s genetic distance were increased by0.1276,0.0020,0.0170and0.0094.