| Cotton is an important natural fiber crop and can provide high-quality natural fiber,high-quality protein and oil.What’s more,it involves nearly 200 million people in the economic source in China.Upland cotton(G.hirsutum)produced more than 95% of the world’s raw cotton,although after a long period of artificial selection to produce a yield,quality,pest and other comprehensive traits of good varieties,but the genetic basis of Upland cotton(G.hirsutum)is relatively narrow.We need to introduce wild Cotton fine traits in cotton breeding process,to improve its quality further.Cotton wild species in the long-term natural selection,the evolution of a large number of excellent characteristics(such as resistance,broad adaptability,etc.),and tetraploid wild cotton and cultivated land of cotton hybrid can be fertile offspring.G.darwinii is a kind of wild tetraploid cotton with drought-resistant,nematode-resistant and fine fineness,which can be used to improve the comprehensive traits of upland cotton(G.hirsutum)cultivars.Genetic linkage map can not only be used to study the structure and variation of genomes,but also for QTL mapping,map cloning,and molecular marker assisted breeding.It is of great significance to construct the genetic map of the hybrid population of upland cotton and wild cotton to evaluate the beneficial allele and molecular marker assisted breeding of wild cotton.Genetic linkage map can not only be used to study the structure and variation of genome,but also plays an important role in QTL mapping,map-based cloning,and molecular marker assisted breeding.In this study,BC1,constructed by CCRI 35 and G.darwinii,was used as the mapping population.Using markers on the genetic map of interspecific cotton(G.hirsutum×G.darwinii)that published,and the genetic map constructed by our laboratory.The main result is as follows:1.Primer polymorphismA total of 3472 of SSR markers were used to screen the polymorphic primers between upland cotton cultivar CCRI35 and wild cotton G.darwinii.Then 1095 polymorphic primer pairs were obtained,accounting for 29.49% of total primers.2.Genotyping BC1 populationA total of 1024 marker loci were used to genotype 92 individuals of BC1 [(CCRI 35×G.darwinii)×CCRI 35],and 1095 loci were obtained.Among them,68 pairs of polymorphic primers produced two polymorphic loci,and one pairs of primers produced three polymorphic loci.Chi-square detection showed that 157 loci deviated from Mendelian genetic separation ratio of 1:1(P<0.05),and the proportion of partial segregation sites was 14.34% in 1095 loci.3.Construction of genetic mapGenetic linkage analysis was performed on 1095 marker sites,and the genetic linkage map was constructed.The map includes 976 marker loci and spans 3383.90 cM,with the average distance of 3.49 cM between the markers.A-subgroup contains 514 marker loci,covering the length of 1657.6cM with the average distance of 3.22 cM between the markers.D genome contains 462 marker loci,covering the length of 1726.3cM with the average distance of 3.74 cM between the markers.Collinearity analysis among G.hirsutum×G.darwinii genetic linkage maps and G.hirsutum physical map showed that the collinearity is good. |
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