Collection And Evaluation Of Major Plum Germplasm In Guangdong Province And Classification Based On Fruit Traits And SNPs

As the largest producing region of plum in China,Guangdong has a group of plum germplasm resources with characteristics of South China such as ‘Sanhua' Plum,‘Zao',and ‘Nanhua'.However,the conservation and use of Guangdong germplasm has been neglected.Some local varieties that existed in the 1980 s have disappeared.Therefore,this study collected and preserved the germplasm of local plums in Guangdong,and conducted a preliminary analysis of their genetic relationship and evolution to promote the conservation and utilization of Plum germplasm resources in Guangdong.By on-site investigation and research methods,24 germplasms with locally distinct traits and 5 germplasms outside the province were collected from major producing areas of Guangdong.In particular,wild plums from Guangdong were first collected;all germplasm materials were preserved by grafting or seedling in the horticultural experiment base of South China Agricultural University in Guangzhou.By 2018,9germplasm blossoms and 6 fruits.Cluster analysis of traits of plum fruit,leaves showed that the clustering results based on the de-redundant fruit trait data are most similar to the traditional classification method of pericarp and pulp color,and the Guangdong Plum species The quality is divided into three groups: red skin red meat(‘Sanhua' et al.),red skin yellow meat(‘Zao'et al.)and green skin yellow-green meat(‘Nanhua' et al.).Among them,the red-flesh red meat group traits differ greatly,with a single fruit weight ranging from 26.82 g('Cong6')to 84.54 g('Ruyuan1')and soluble solids content from 7.27%('Ying6').)to 14.18%('Xiaomi'),the overall can be divided into 'Conghua Sanhua','Mi','Ji ma','Ying zhi Sanhua' four types.Using the SLAF sequencing technology,34 plum germplasms were classified,and agroup of specific SNP loci were identified.A number of species-specific SNP sites were identified,of which there were 350 ‘Zao' and 475 “Chuahua Sanhua”.Six phylogenetic trees were constructed using the maximum likelihood method and the least-neighbor adjacency method.The topological structures were very similar to each other,and the materials were divided into 6 groups(C1~C6)stably.‘Sanhua' and Plum of north of Guangdong show a continuous variation,and can be divided into three groups according to the among of differences compared with the Northern variety(C2): 1.'Bai cui ji ma'and 'Xiaomi' in Shaoguan(C3);2.'Yingzhi Sanhua' in Xingning(C5);3.'Conghua Sanhua'(C6).Compared with other ‘Sanhua' in Guangdong,the genotypes of 'Yingzhi Sanhua' are relatively homozygous,while 'Conghua Sanhua' is rather heterozygous,combining morphological traits with phylogenetic relationships to speculate that 'Yingzhi Sanhua' is the ancestor of ‘Conghua Sanhua'.The ‘Zao'(C4)has the characteristics of typical early mating,low chill requirement,and high genotype heterozygosity.It may originate from the hybridization of wild plum(C1)and other plums adapted to the environmental conditions in Guangdong.‘Nanhua' has low genetic diversity and is less associated with other Plum germplasms in Guangdong.Although with a long cultivation history in Guangdong,it belongs to exotic varieties.