Integration of Rps2, Rmd, and Rj2 into linkage group J of the soybean molecular map.

Reference Report for IND20432150

Title:	Integration of Rps2, Rmd, and Rj2 into linkage group J of the soybean molecular map.
Authors:	Polzin, K.M., Lohnes, D.G., Nickell, C.D., Shoemaker, R.C.
Source:	J. Hered. 1994, 85(4):300-303
Abstract:	To correlate the classical soybean linkage map with the USDA-ARS molecular map, genes from the classical map must be located relative to molecular markers. The purpose of this study was to integrate the genes for ineffective bradyrhizobia nodulation (Rj2), powdery mildew resistance (Rmd), and phytophthora root and stem rot resistance (Rps2) from classical linkage group 19 with the molecular map. A population of 202 F2 lines was derived from a cross of two Williams isolines containing the genes Rj2 Rmd-c Rps2 Ti-a and rj2 rmd rps2 Ti-b. The lines were classified for their reactions to bradyrhizobia, powdery mildew, and phytophthora, and for the Kunitz trypsin mobility variant. Restriction fragment length polymorphism analysis identified three loci from linkage group J (A233, A724, and K375) that were polymorphic between the parent lines. Segregation analysis revealed close linkage between the genes and group J markers, thus correlating linkage group J to classical linkage group 19. The most likely order of the loci was Rps2 Rmd Rj2 A233 A724 K375 (log-likelihood--193.73), with the three genes contained within a 3.8 cM region. This region of the soybean molecular map harbors the densest collection of agronomically important genes identified to date, making it a suitable target for map-based cloning in soybean.

Funded by the USDA-ARS. Developed by the USDA-ARS SoyBase and Legume Clade Database group at the Iowa State University, Ames, IA

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