Molecular Evaluation And Flavonoids Profiles In F1 Hybrids Derivated From Crossings Between Chuhongyou And Feicuiyou (Citrus Grandis)

Hybrid population is not only used for citrus breeding,but also for locating key genes via linkage map construction,genotype by sequencing（GBS）and quantitative trait locus（QTL）analysis.In order to explore the heredity of flavonoids in citrus as well as seek key genes in the metabolic network,in 2012,we created the hybrid population between two pomelo cultivars（Citrus grandis）,Chuhongyou and Feicuiyou.In this study,true hybrids were selected out and then the flavonoids in the these seedlings were analyzed,besides,an early flowering mutant in this population was primarily studied,the main results were as follows:1.Ma6-64,Ma3-104,Ma3＿198,Csin.0495 and Ma3-954,five pairs of SSR primers were selected for hybrid identification.Finally,823 hybrids were identified from CF which contains 952 plants,while 83 hybrids were identified from FC which contains 93plants,the total hybrid rate is 86.7%.These individuals were used for further study.2.14 flavonoids in the leaves of Chuhongyou,Feicuiyou and their hybrids were analyzed via HPLC detection.Firstly,naringin and rhoifolin were identified by comparing with standards;furthermore LC-MS analysis showed that W₁,W₃,W₄,W₆and W₉might be classified as apigenin glycosides.The mass charge ratio of W₁and W₃are595 and 565 respectively,they might be apigenin-6,8-di-C-hexosidase and apigenin-8-C-glucoside-O-pentoside,respectively.3.The relative quantitative analysis via HPLC analysis showed that the content of flavonoids in Chuhongyou and Feicuiyou F1 hybrids lyophilized spring shoot leaves are not normally distributed.It could be regulated by both major genes and polymicrogenes.Naringin and rhoifolin as major flavonoids in sampls,their content range were112.45¹5118.44μg/g and 73.70～9496.94μg/g respectively;variation coefficient were156%and 59%respectively,the F1 hybrids average content were 1431.49μg/g and3118.13μg/g respectively,genetic heritability are 168.47%and 120.14%respectively.The content of naringin showed a decreased tendency in offsprings,while,the content of rhoifolin showed an increasing tendency in offsprings.4.Flavonoids in progenies of CF population had a little inclining to chuhongyou（female parent）via principal component analysis（PCA）and cluster analysis,meanwhile,CF803,CF907,CF527,CF534,CF563,CF579,CF586,CF598 etc were selected out as special germplasms for further study.5.We cloned genes ELF3,AP1,SOC1,LFY,TFL1,SVP that related to early flowering phenotype.A specific transcription of ELF3 was found in early flowering pomelo CF854 comparing with controls through nucleotide and amino acid sequence alignment analysis.The correlation between specific transcription of ELF3 and early flowering mutation need further study.