A single recessive gene, rxp, controls bacterial leaf pustule (BLP) resistance in a soybean. The Rxp locus appears to be linked to the malate dehydrogenase (Mdh) locus and Satt372 on linkage group (LG) D2. Around the Rxp locus, four bacterial artificial chromosome (BAC) clones are anchored by Satt486, Satt498, BARC-022037-04263, and BARC-040963-07870. Using these BAC clone sequences, possible orthologous region of Rxp locus was identified: Medicago truncatula contig 962 at chromosome 3 and contig 283 and contig 1108 at chromosome 8. Sequence analysis of contig 962 had revealed microsynteny with three soybean BAC clones on LG A1, which are duplicated with other two soybean BAC clones anchored by Satt486 and Satt498. After BLAST search was performed with M. truncatula contig 962 against soybean ESTs, several soybean ESTs were identified. With developed single nucleotide polymorphism (SNP) markers and the RIL population from the cross of Pureunkong and Jinpumkong 2, SNP genotyping was able to locate twos oybean ESTs: CO979743 at 1 cM away from Satt195 on LG C1 and BE021935 at 5 cM away from Satt363 on LG C2. Thus, our results indicate that structure of soybean genome around Rxp locus is very complicated.

A new sprout-soybean cultivar, “Wonhwang” was developed at the Honam Agricultural Research Institute (HARI) in 2005. Wonhwang was selected from a cross between Camp and Myeongjunamulkong. The preliminary, advanced, and regional yield trials for evaluation and selection of Iksan45 were carried out from 2001 to 2005. This cultivar has a determinate growth habit with purple flower, grayish brown pubescence, grayish brow hilum, lanceolate leaflet shape and small seed size (10.0 grams per 100 seeds). The maturity date of Wonhwang is 7 days earlier than that of the check variety, Pungsan. It has good seed quality for soybean-sprout, and resistance to lodging. It has also been identified to have resistance to soybean mosaic virus (SMV) and necrotic symptom(SMV-N). The average yield of “Wonhwang” was 2.80MT/ha, which was higher by 4% than “Pungsannamulkong” at the regional yield trials.