Identification And Evaluation Of Fiber Quality Traits Of Recombinant Inbred Lines Population From Upland Cotton

Cotton is not only the world's major natural fiber crop,but also an important cash crop.In recent years,with the rapid development of the textile industry and the continuous improvement of textile technology,the requirements for fiber quality are getting higher and higher.Therefore,it becomes an important breeding direction to improve the fiber quality of cotton in China while ensuring cotton yield.In this study,two upland cotton varieties,Nongda 601 and Nongdamian 13,which have large differences in cotton fiber quality and yield traits and were widely planted in large-scale production,were used as parents.A set of 590 was constructed by means of hybridization and self-crossing.In order to identify and evaluate the fiber quality traits,the phenotypic identification test of the recombinant inbred lines(F7:8)was conducted in Qingxian,Qingyuan of Hebei and Luntai of Xinjiang.Six major fiber quality traits such as fiber length,breaking strength,micronaire value,elongation ratio,uniformity index,and spinning consistent index were evaluated,and the genetic variation level of the population was determined.Elite cotton new materials were further selected.This study will be of great significance for QTL mapping of fiber quality traits and high quality breeding cotton.The main results are as follows:1.In the three environments,there were significant differences in the six fiber quality traits between the two parents and the RILs population.The average of fiber length of the male parent Nongda 601 and the female parent Nongdamian 13 was 27.59 mm and 30.72 mm,respectively.The average of breaking strength was 28.51 c N/tex and 34.31 c N/tex,the average value of micronaire is 5.13,4.59,the average of elongation ratio is 6.80%,6.59%,and the average value of uniformity index is 85.74%,86.68%.The average spinning consistent index was 140.75,163.75.The range of variation of the RIL population was significantly beyond the range of the parents,and there were super high-parent and super low-parent types.This indicates that the RIL population is a good population for QTL mapping of fiber quality traits.2.Variance analysis of fiber quality traits in RILs populations under three environments showed that genotype,environment,genotype and environment interaction had significant effects on cotton fiber quality traits.Correlation analysis of various traits showed that fiber length was significantly positively correlated with breaking strength,uniformity index and spinning consistent index,and was significantly negatively correlated with micronaire value and elongation ratio.The breaking strength was significantly negatively correlated with the micronaire value and elongation ratio,and was significantly positively correlated with the uniformity index and the spinning consistent index.The micronaire value were all significantly negatively correlated with elongation ratio,uniformity index and spinning consistent index.The uniformity index and the spinning consistent index are extremely significantly positively correlated.3.According to the criteria of high-quality cotton,23 strains with grade AA or above in three environments were selected from the RIL populations,namely 2017SN-13?2017SN-80 ? 2017SN-89 ? 2017SN-94 ? 2017SN-99 ? 2017SN-137 ? 2017SN-183 ?2017SN-191?2017SN-226?2017SN-294?2017SN-346?2017SN-359?2017SN-384?2017SN-386?2017SN-392?2017SN-445?2017SN-468?2017SN-476?2017SN-484?2017SN-503?2017SN-522?2017SN-541?2017SN-584.Among them,2017SN-584 with grade AAA reached 30 mm or above in the fiber length,and 32 c N/tex or above in fiber breaking strength.In summary,the genetic variation of six fiber quality traits in parental and RIL populations were clarified.Genotype,environment,genotype and environmental interaction had significant effects on fiber quality traits.There were different degrees of correlation among fiber quality traits.Twenty-three lines with excellent fiber quality were screened.This research has provided reliable phenotypic data for QTL mapping of fiber quality traits in upland cotton and excellent germplasm for high quality cotton breeding.