The soybean Kunitz trypsin inhibitor (KTI) protein is responsible for the inferior nutritional quality of unheated or incompletely heated soybean meal. Ti locus controls presence or absence of Kunitz trypsin inhibitor protein. Genetic recombination or tight linkage between Ti locus and Satt228 marker that has been identified to be tightly linked to the Ti locus was detected for marker assisted selection (MAS) using two F2 populations of titi genotype in this study. Two F2 populations were developed from the cross of A29 (KTI protein present, TiTi genotype, AA genotype in Satt228 marker) x Gaechuck#1 and Gaechuck#2 (KTI protein absent, titi genotype, BB genotype in Satt228 marker). Among 31 F2 plants derived from A29 x Gaechuck#1, twenty nine F2 plants show BB genotype that indicates no recombination between Satt228 marker and Ti locus. Only 2 F2 plants show AA genotype that indicates recombination between Satt228 marker and Ti locus. Twenty eight F2 plants derived from A29 x Gaechuck#2 show BB genotype that indicates no recombination between Satt228 marker and Ti locus. Expected genetic ratio between Satt228 marker and Ti locus was 3.6 cM in F2 population.

Soybean has a morphological type with a broadened and flattened stem. Fasciation has been suggested as a new gene for soybean research. SSR marker linked to the ~Large f locus that controls fasciation phenotype has not identified within 10 cM. A mapping population consisting of 94 F2 progenies was derived from a cross between wild type Clark (FF) and fasciation mutant C32 (~Large f~Large f ). The phenotype of F2 individual plants was recorded at R2 and R3 growth stage from field. One-thousand 10-mer oligonucleotide RAPD primers and 29 SSR primers selected from the D1b+W of the soybean molecular linkage map were used. A genetic map was constructed from the segregating 35 RAPD, four SSR markers and one phenotypic(wild type/fasciation) marker. The segregation ratios of 3 : 1 observed in the F2 population and the Chi-square values strongly suggest that the fasciation trait is controlled by a single recessive gene. Satt537 marker was linked to ~Large f locus at a distance of 9.6 cM. Assignment of the ~Large f locus to linkage group D1b+W and identification of markers can be used as an initial step for fine mapping of the ~Large f gene.