| Potato is one of the important grain crops.With the implementation of the national strategy of potato staple food,the market demand for starch,powder,chips and crisps processing special potato varieties is increasing.In order to cultivate new potato processing varieties with high starch and high dry matter content,construct a high-density molecular genetic linkage map of potato,and identify QTL for important quality and yield traits,in this experiment,a total of 182 F1 individuals were obtained from a cross of the tetraploid potato 'YSP-4'×'MIN-021',and their genomic DNA were extracted.Using SRAP and SNP molecular markers,we constructed the high density genetic linkage maps of their parents,and measured the starch content,dry matter content,yield per plant and marketable potato rate of F1 segregation population under four different environmental conditions of two years and two locations to identify the stable major QTL.This research can lay a foundation for further research on QTL fine mapping of important traits such as quality and yield,map-based cloning,functional analysis of related genes,and molecular marker-assisted breeding of potato.The main results are as follows:1.A total of 36 polymorphic SRAP primers were screened and used to amplify the genomic DNA of 182 individuals of potato hybrids and their parents.A total of 742 SRAP bands were obtained,of which 598 were polymorphic,with a polymorphic rate of 80.59%.2.A total of 3,001 stable SNP markers for genetic mapping were detected based on SLAF-seq high-throughput genome sequencing technology.3.The marker segregation distortion analysis showed that the maternal map contained 1,995 molecular markers,of which 157 were distorted markers,with a segregation distortion ratio of only 7.87%,while the paternal map contained 1,776 molecular markers,of which 97 were distorted markers,with a segregation distortion ratio of only 5.46%.This meets the requirement that the segregation distortion ratio of plant genetic mapping is less than 30%.4.Using the strategy of two-way pseudo-testcross,two high-density genetic maps from both parents were constructed,and each map contained 12 linkage groups.The maternal map covered the genome length of 1,829.19 cM,containing 1,995 markers,with an average map distance of 0.92cM,while the paternal map covered the genome length of 1,810.44 cM,containing 1,776 markers,with an average map distance of 1.02 cM.5.The four phenotypic characters starch content,dry matter content,yield per plant and marketable potato rate of tetraploid potato F1 population showed normal distribution,and there was a certain degree of correlation and significant difference between them.6.Based on the constructed high-density genetic maps,we identified QTL for four important traits of tuber starch content,dry matter content,yield per plant and marketable potato rate.A total of 23 stable QTLs were detected,of which 11 stable QTLs from paternal map,including five starch content QTLs,three dry matter content QTLs,two yield per plant QTLs and one marketable potato rate QTL,and the genetic contribution rate varied from 10.6%to 41.7%.A total of 12 stable QTLs from maternal map were identified,including one starch content QTL,six dry matter content QTLs,three yield per plant QTLs and two marketable potato rate QTLs,and their genetic contribution rate varied from 10.7%to 44.8%.7.Of all the 23 stable QTLs,seven were major QTLs.There were three major QTLs identified from paternal map,including two QTLs controlling starch content(qLM7SC45 and qLM7SC46)and one controlling yield per plant(qLM4TY22),and the genetic contribution rate ranged from 20.7%to 41.7%.In the maternal map,four major QTLs were identified,of which one QTL controlled starch content(qLF5SC16),three QTLs controlled dry matter content(qLF4DM11,qLF1M23 and qLF5DM65),and the genetic contribution rate varied from 26%to 44.8%. |
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