Genetic Variation Of 100-Seed Weight And Maturity In Soybean (Glycine Max L.Merr.) Detected By Using TILLING And EcoTILLING Techniques

Soybean(Glycine max L.Merr.)is one of the important world commodities because of its unique chemical composition,high nutritional value,functional health benefits and industrial applications.To meet the increasing demandof soybean,discovering of gene related to soybean yield is very important for breeding purposes.Mutation discovery through TILLING and EcoTILLING approaches provide direct functional approach to link genotype to phenotype.A total of 1046(EMS treated and untreated)soybeans were investigated for induced mutation and natural variations.Three target genes related to yield were studied,including IKU2(Glyma.13g253300)a homologous gene of AtIKU2 involved in seed size,E4(GmPhyA2;Glyma.20g22160)and E3(GmPhyA3;Glyma.19g224200)genes related to soybean flowering and maturity.1.By using TILLINGtechnology,476 M3 lines from EMS population were investigated for three genes.A total of 16 induced mutations,with total mutation density reached 1/581 kb.Induced mutations distributed as 1 silent,3 missense and 4 intronics detected in IKU2,while 3 silent,and 5 missense mutation detected in E4 gene.These mutations were detected in IKU2,and E4,while E3 showed difficulties to reveal mutations in mutagenesis soybean.Based on these nucleotide variations 2haplotypeswere deduced in IKU2,and 8 in E4.2.By using EcoTILLING technology,a total of 570 soybean cultivars were also investigated for three genes,showed mutation rate of1/400 kb.The result revealed 15 nucleotide variations in IKU2 gene and E4 except E3.ForIKU2 6 nucleotide variations were uncovered in 27 soybean accessions.These variations distributed as 1 silent,2 missenses and 3 introns.Threehaplotypeswere deduced and associated with seed size.Using obtained nucleotide variations UPGMA phylogeny tree was constructed,revealed that soybean accessions structured according to thedistinguishedhaplotypes.EcoTILLING of E4 gene identified 9 nucleotide variations including 3 silent and 6 missense,that deduced 8 haplotypes.UPGMA phylogeny tree was also constructed from the detected natural variations,revealed 2 major groups with other subgroups.3.By integrating the two populations,IKU2andE4 had 8 and 10 nucleotide variations respectively.The natural population has 2 more variations inIKU2 and mutagenesis population had 2 more variationsinE4.The results indicated that alleles found in different populations can broaden the source of gene.