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.

Riptortus clavatus, one of the many insects in major crops, damages pods and seeds, which reduces seed vigor and viability in soybeans. This study was conducted to examine the effect of diversely damaged seeds by R. clavatus on seed germination and seedling emergence and to determine the association of damaged seed with quality and yield of soybean sprouts. All seeds damaged by R. clavatus significantly (P<0.05) reduced seed vigor as measured by the rates of seed germination, germination speed, and seedling emergence. Mean seed germination rate of non-damaged seeds in sprout-soybean varieties was 97.8%, whereas the rates of seeds damaged at different levels, 31-50% and 51-80%, were 23.0 and 5.4%, respectively. The rates of seedling rot and abnormal, incomplete germination significantly (P<0.05) increased as the amount of seeds damaged by R. clavatus increased to 5, 10 and 15% against the total seeds for sprout production. Yield of soybean sprouts from seeds damaged at different levels decreased up to 13% as compared to that in normal seeds. In customer preferences on soybean sprout produce, 84% of customers participated in survey preferred to purchase sprouts from seeds with 5% of damaged seeds, but sprouts produced from seeds with 15% of damaged seeds were intended to purchase only by 22% of the customers. Areas of the seed damaged by R. clavatus were readily infected by pathogens as the seed germinated, resulted in deteriorated quality and reduced yield of sprout produce.

Transgenic plants that over express virus coat protein genes have attracted particular interest from researchers, by virtue of their tolerance to virus infection. The transgenic watermelon rootstock analyzed in this study was established by introducing CGMMV coat protein (cp) under the control of CaMV 35S promoter and NOS terminator (Park et al., (2005) Plant Cell Rep. 24: 350-6). The primary objective of this study was to determine the copy number and integration site of the transgene element, in order to develop detection techniques required for monitoring of the transgenic watermelon rootstock. The Southern blot analysis indicated that a single copy of CGMMV-cp gene was inserted into the genome of transgenic watermelon rootstock. We also identified the genomic sequences flanking the integration site of the transgene by inverse PCR analysis. In an effort to find a sequence usable as an internal positive control for the screening of the watermelon and watermelon rootstock, we found that the Sat and DIP-1 genes appears as one copy within their genomes and is watermelon rootstock- and watermelon-specific. The information of the integrated site and the internal positive control sequence was used to establish a new event-specific PCR-based detection method. In addition, mRNA and protein expression level of the transgene in the transgenic watermelon rootstock and grafted watermelon were investigated. The expression of both mRNA and protein of CGMMV-CP was not detected in the transgenic watermelon rootstocks and watermelons, suggesting that the movement of transgene products from transgenic rootstock to watermelon does not occur at our detection level.