Establishment Of The Core Collection Of Male Germplasm Resources Of Actinidia Eriantha And Analysis Of Its Genetic Diversity

Actinidia eriantha is one of the important species of Actinidia Lindl.It is a unique germplasm resource and widely distributed in China.In this study,207 male plants of A.eriantha were collected as experimental materials.The core germplasm was constructed based on "phenotypic traits + SSR molecular markers" and its genetic diversity was studied.The DNA fingerprint of the core germplasm was constructed.The main results are as follows:(1)The primary core collection of male plants of A.eriantha was constructed at the phenotypic level.31 core materials were obtained from 207 male germplasms of A.eriantha,with a sampling rate of 14.95%.The best sampling strategies were: euclidean distance + multiple clustering priority sampling + class average + 15% sampling ratio,range coincidence rate(CR),coefficient of variation(VR),phenotype retention ratio(RPR),Shannon diversity index(H)were 97.98%,130.54%,100.00% and 1.78,respectively.The t-test of genetic diversity index of 11 traits showed that there were no significant differences in other traits except pollen vigor.The principal component analysis showed that the primary core collection could well represent the original collection.Based on the significant difference of pollen viability in t-test of genetic diversity,the primary core collection was supplemented and the initial core collection was changed to 44.(2)The core collection of male plants of A.eriantha was constructed at the molecular level.44 male germplasms of A.eriantha reached 26 core collection based on rare allele preferential sampling method,with a sampling ratio of 59.09%.The allele number(n),average allele number(Na),average effective allele number(Ne),average Shannon index(I),average expected heterozygosity(He),average Nei's genetic diversity index(H)and average polymorphic information content(PIC)of 44 initial core collection amplified at 23 SSR loci were 241,10.4348,5.7512,1.8647,0.7814 and 0.7,respectively.716 and 0.778.The above parameters of 26 core germplasms were 234,10.087,6.104,1.916,0.810,0.792 and 0.796,respectively.The retention ratio of alleles and phenotypic retention ratio in core germplasm was 97.10% and 97.92%,eliminating the genetic redundancy in the original germplasm,improving some parameters of genetic diversity,and representativeness of the constructed core collection was better.(3)The genetic diversity and cluster analysis of 26 male core collection were carried out by SSR markers,and DNA fingerprints were constructed to lay a foundation for molecular marker breeding of kiwifruit.The genetic diversity and molecular fingerprint of male core collection of A.eriantha were analyzed.The polymorphism of 23 primers was analyzed.The results showed that 234 DNA bands were amplified from 26 core collection,of which 234 were polymorphic,and the ratio of polymorphic bands was 100%.Theprimers with the most bands were UDK99-143,reaching 21,and the primers with the least bands were 22,only 6.The PIC value of SSR primer polymorphism information content was 0.480-0.935,and the average polymorphism information content was 0.796.At least two pairs of polymorphic primers(UDK99-143 and A055)were needed from 23 primers to distinguish the tested germplasms completely.Molecular fingerprints were constructed to obtain the unique DNA molecular fingerprints for each germplasm.The core collection tree map can be divided into eight categories.