Evaluation And Molecular Marker Screening Of Main Traits Of Peanut Chromosome Segment Substitution Lines

Peanut(Arachis hypogea L.)is one of the main cash and vegetable oil crop in the world,which accounts for a large proportion in the national economy and people's life.The main traits of peanut are mostly quantitative traits,such as agronomic and quality traits,etc.The differences of these traits are determined by both genes and environment,and their genetic law are relatively complex,which makes it more difficult to directly select in breeding.Identification of quantitative trait locus(QTLs)of some agronomic traits is of great significance in the development of molecular marker-assisted breeding,and potential improvement of crop yield.Chromosome Segment Substitution Lines(CSSLs)is an ideal populations for QTL mapping with the advantages of simple genetic background and small population variation.In this study,a CSSLs population with 345 lines constructed by a small multi-pod germplasm Shiyaodou(fa.)as donor parent,ordinary good big pods material of Qinhuangdaoguangyang(hea.)as receptor parent and 768 SSR markers were used as materials.Agronomic and quality traits of the CSSLs population were evaluated,and molecular markers related to those traits were screened.the results are as follows:1.The agronomic and quality traits of CSSLs populations were normally distributed,which followed the typical genetic characteristics of quantitative traits.In the two environments of 2017 and 2018,the variation coefficient of pod traits of CSSLs population ranged from 5.84% to 15.18%,among which the variation coefficient of shelling percentage was the smallest and the 100-pod weight was the largest.The variation coefficient of quality traits of protein ranged from 2.56% to 7.49%,among which the protein variation coefficient was the smallest and stearic acid variation coefficient was the largest.2.The results of variance analysis showed that there was no significant inter-annual difference in pod length among agronomic traits of CSSLs groups,but significant inter-annual difference in pod width,Shelling percentage,100-pod weight and 100-kernel weight,there were significant differences between lines,and significant interaction effect between population genotype and environment.3.There were extremely significant positive correlation between pod length with pod width,100-pod weight and 100-kernel weight,and extremely significant negative correlation with shelling percentage.The pod width was extremely significant negative correlation with the shelling percentage,and extremely significant positive correlation with the 100-pod weight and 100-kernel weight.The shelling percentage was extremely significant positive correlation with the 100-kernel weight,and extremely significant negative correlation with the100-pod weight.There was a significant positive correlation between 100-pod weight and 100-kernel weight.The oil content was extremely significant positive correlation with protein content and oleic acid content.The protein content was extremely significant negative correlation with stearic acid content and oleic acid content,negative correlation with behenic acid content and positive correlation with linoleic acid content.Palmitic acid content was extremely significant positive correlation with stearic acid content,linoleic acid content and behenic acid content,and extremely significant negative correlation with oleic acid content and arachidonic acid.The stearic content acid was extremely significant positive correlation with arachidonic acid and behenic acid content.The oleic acid content was extremely significant negative correlation with linoleic acid content and behenic acid content,and positive correlation with arachidonic acid content.The linoleic acid content was extremely significant negative correlation with the content of arachidonic acid content,and was extremely significant positive correlation with behenic acid content.4.Through evaluation,analysis and screening of agronomic and quality traits of CSSLs population,twenty three lines with multi-seed type with annual average expression were obtained;Eight lines with the traits of 100-pod weight,100-kernel weight and Shelling percentage showed positive heterobeltiosis advantage in two years.Six lines with high oil content and low palm were selected.One arachidonic acid line was screened out.A line with positive heterobeltiosis of oleic acid and linoleic acid was screened.A line with negative heterobeltiosis in Shelling percentage in two years was obtained..5.The pod width,shelling percentage,100-pod weight and 100-kernelweight conforms to the genetic model of two main gene effects,and the pod length was in line with the genetic model of three main gene effects in 2017.The oil contents,stearic acid,linoleic acid and arachidonic acid were consistent with the additive genetic model.The pod length followed the genetic model of one pair of main genes.The pod width,shelling percentage,100-pod weight and protein contents,palmitic acid,oleic acid and behenic acid satisfied 2 pairs of main gene genetic models,and 100-kernel weight was in line with the genetic model of three main gene effects in 2018.6.A total of 768 SSR primers were screened in 345 lines.The results showed that 25 pairs of primers were amplified polymorphic bands in the population,and nine markers were significantly correlated with the pod traits by stepwise regression analysis in CSSLs population.Eight primers were significantly correlated with quality traits in CSSLs population.Phenotypic identification of agronomic and quality traits and screening of related molecular markers in the population of CSSLs population laid a foundation for QTL localization,provided excellent materials and important references for marker-assisted breeding and mining related genes.