Soybean proteins are widely used for human and animal feeds worldwide. The use of soybean protein has been expanded in the food industry due to their excellent nutritional benefits. But, antinutritional and allergenic factors are present in the raw mature soybean. P34 protein, referred as Gly m Bd 30K, has been identified as a predominant immunodominant allergen. The objective of this research is to identify the genetic mode of P34 protein for the improvement of soybean cultivar with a very low level of P34 protein. Two F2 populations were developed from the cross of "Pungsannamulkong" x PI567476 and "Gaechuck2ho" x PI567476 (very low level of P34 protein). Relative amount of P34 protein was observed by Western blot analysis. The observed data for the progeny of "Pungsannamulkong" and PI567476 were 133 seeds with normal content of P34 protein and 35 seeds with very low level of P34 protein (X2=1.157, P=0.20-0.30). For the progeny of "Gaechuck#1" and PI567476, the observed data were 177 seeds with normal content of P34 protein and 73 seeds with very low level of P34 protein (X2=2.353, P=0.10-0.20). From pooled data, observed data were 310 seeds with normal content of P34 protein and 108 seeds with very low level of P34 protein (X2=0.156, P=0.50-0.70). The segregation ratio (3:1) and the Chi-square value obtained from the two populations suggested that P34 protein in mature soybean seed is controlled by a single major gene. Single gene inheritance of P34 protein was confirmed in 32 F2 derived lines in F3 seeds, which were germinated from the low level of P34 protein obtained from the cross of "Pungsannamulkong" and PI567476. These results may provide valuable information to breed for new soybean line with low level of P34 protein and identification of molecular markers linked to P34 locus.

Dwarfuess and Kunitz trypsin inhibitor (KTI) protein in soybean is useful traits for basic studies. df2 and ti gene control dwarfness and the expression of Kunitz trypsin inhibitor (KTI) protein in soybean, respectively. The objective of this research was to verify genetic linkage or independent inheritance of df2 and ti loci in soybean. The F2 population was made by cross combination between "Gaechuck#2" (Df2Df2titi genotype, KTI protein absence and a normal growth type) and T210 (df2df2TiTi genotype, a dwarf growth type and KTI protein present). A total of 258 F2 seeds were analyzed for the segregation of KTI protein using SDS-PAGE. And so, 198 F2 plants were recorded for the segregation of dwarfness. The segregation ratio of 3 : 1 for Ti locus (201 Ti : 57 titi) and Df2 locus (143 Df2 : 55 df2df2) was observed. Segregation ratio of 9 : 3 : 3 : 1 (116 TiDf2: 44 Tidf2df2: 27 titiDf2: 11 titidf2df2) between df2 gene and ti gene was observed (x2 =3.53, P = 0.223). These results showed that df2 gene was inherited independently with the ti gene in soybean.