| Short season cotton,also known as early maturing cotton,is a kind of Upland Cotton with short growth period.The breeding and popularization of short season cotton varieties have optimized the farmland planting system and greatly alleviated the problem of cotton and grain planting time.However,lint yield of short season cotton varieties was significantly lower than that of middle and late maturity cotton varieties.Lint percentage is an important yield component trait of cotton,which is controlled by genotype and environment.A large number of studies have shown that the improvement of cotton yield is closely related to the increase of lint percentage.Therefore,it is very important to study the genetic basis of short season cotton coat traits.In this study,short season cotton varieties Dong 3,Dong 4 and 240 RIL populations were planted in Xinxiang,Henan,China and Shihezi,Xinjiang,China for three consecutive years to study the traits of short season cotton coat and analyze the genetic basis of short season cotton coat.Firstly,DNA of short season cotton varieties Dong 3,Dong 4 and their RIL populations were extracted for genome re sequencing,polymorphic markers were detected to construct genetic map,and stable lint QTLs were mined.Then ovules or fibers of Dong 3 and Dong 4 materials with 0 DPA,5 DPA,10 DPA and 15 DPA were taken for RNA SEQ to find out the differential genes among parents at different stages.Finally,the candidate genes related to lint were found by combining the QTL mapping results of lint and RNA SEQ data analysis,Furthermore,the genetic basis of lint percentage was analyzed to provide reference for the breeding of high-yield short season cotton varieties.The main results are as follows:1.DNA extracted from young leaves of short season cotton varieties Dong 3,Dong 4 and 240 RIL populations was used for genome re sequencing.The genetic map was constructed with 4960high-quality bin markers.The total length of the genetic map was 3971.08 cm and the marker density was0.80 cm.Based on phenotypic data and re sequencing data,17 QTLs（including repeats）were located in five environments,explaining 2.9064 ～ 11.3871% of the phenotypic variation of lint percentage;Three lint stable QTLs（q LP-D04,q LP-A02 and q LP-D12）were detected;QTL of lint percentage（q LP-D04）on chromosome D04 was detected in 5 environments,which explained 6.2495 ～ 11.3871% of phenotypic variation of lint percentage;QTL（q LP-A02）on chromosome A02 was detected in three environments,which explained 5.0987 ～ 6.1277% of the phenotypic variation of lint percentage;QTL（q LP-D12）located on D12 chromosome was detected in two environments and explained 5.2225% and 3.603% of the lint phenotypic variation.By comparing the reference genomes of upland cotton,227 candidate genes were detected within the confidence intervals of the three QTLs.2.the ovules or fibers at 0dpa,5dpa,10 dpa and 15 dpa of winter 3 and 4 were used as materials to extract RNA for RNA SEQ.Combining the transcriptome data of the two parents at different developmental stages,the 0 DPA,5 DPA,10 DPA and 15 DPA of dong3 were compared with those of dong4,and the differential genes between the parents at each stage were obtained.By comparing the confidence intervals of three stable QTLs,28 differential genes were screened in four periods.Go classification and molecular function enrichment analysis were carried out for these 28 differential genes.Finally,14 genes related to lint percentage were detected in 12 significantly enriched molecular function items.This study considered that they were potential candidate genes for lint percentage.The homologous genes of these genes were found in Arabidopsis thaliana.Based on the analysis of biological information,their homologous genes were mainly related to some proteins and lyase activities,which provided some useful information for confirming their effects on short season cotton LP.In order to find out the genetic basis of short season cotton lint,further functional identification of these differential genes is needed. |
PDF Full Text Request