Construction Of Cold-resistant Wine Grape Group And QTL Analysis Of Cold-resistance

Germplasm resources are the basis of all breeding work,and it is of great significance to the grape industry to cultivate new varieties of high-quality cold-resistant wine grapes.The emerging molecular-assisted breeding technology can use molecular markers to select the offspring at an early stage,thereby accelerating the breeding process of cold-resistant and high-quality grape varieties and shortening the breeding cycle.In this study,with the cold-resistant vitis amurensis variety‘Shuanghong’as the female parent and the non-cold-resistant Eurasian grape variety‘Italian Riesling’as the male parent,both the two parents and their 98 hybrid seedlings were tested in 2019 and 2020 for fruit quality and cold resistance.Using WGS（Whole Genome Sequencing）to construct a genetic map of vitis amurensis,and finally combining the genetic map with the phenotype data of two-year cold resistance,the QTL locus of the cold resistance of grapes was located and the candidate genes were preliminarily predicted.The main findings are as follows:1.A total of 98 hybrid seedlings in 2019 and 2020 were tested for fruit quality and cold resistance identification and analysis.The fruit quality of the hybrid F1,including soluble solid content,fruit stalk length and seed number,showed transgressive inheritance.The selection of these two parents for crossbreeding will produce a broad trait segregation group.The semi-lethal temperature of F1 was measured by the conductivity method and then its cold resistance was comprehensively evaluated by the membership function method.The results showed that F1presented obvious separation in the cold resistance phenotype,showing a normal distribution,and the cold resistance traits were quantitative traits,controlled by minor effect polygenes.The final results obtained by the membership function method and the semi-lethal temperature are the same.This group has significant advantages and can be used for subsequent genetic map construction and QTL detection.2.Using WGS（Whole Genome Sequencing）to sequence and analyze the genomes of‘Shuanghong’בItalian Riesling’and their 98 F₁ plants,a high-density SNP molecular genetic map of grapes was constructed.The map results are as follows:the female parent‘Shuanghong’obtained a total of 24875 markers,covering the total map distance of 2123.62 c M,and the average distance among sites was 0.09 c M;the male parent‘Italian Riesling’obtained a total of 18,832markers,covering the total map distance of 2586.05 c M,and the average distance among the sites was 0.14 c M;the integrated map obtained a total of 42680 markers,the total map distance was2309.15 c M,and the average distance among the markers was 0.05 c M.3.With the help of the mapping software Map QTL5.0 and the location software R/qtl,combining the two-year cold resistance phenotype identification results of‘Shuanghong’בItalian Riesling’and their 98 progenies with the constructed high-density molecular genetic map,28 QTL locus（LOD≥3.0）related to the cold resistance of grapes were obtained,which were distributed on the LG5,LG7,LG13,LG14,LG16,LG18 and LG19 linkage groups,and the contribution rate was between 14.4%and 20.1%.4.Finding out all the genes in the QTL locus range,and screening out 7 candidate genes,including GLPs,RPK,GSH,Lipoxygenase,Laccase,KCS and TMV resistance protein N-like,which may be related to grape cold resistance based on gene annotation.