Soybean seed protein electrophoresis profiles from 15 Asian countries or regions: Hypotheses on paths of dissemination of soybeans from China

Soybean Glycine max (L.) Merr.] seed protein extracts from 1,603 accessions obtained from 15 Asian countries or regions (not including Japan) were analyzed for the presence of alleles of 2 proteins. Three alleles of the Kunitz. trypsin inhibitor orSBTI-A ₂ designated asTi ^a,Ti ^b andTi ^c are electrophoretically distinguishable from one another by their different Rf values of 0.79, 0.75 and 0.83, respectively. The Sp₁ seed protein or β-amylase has 2 alleles designatedSp1 ^a andSp ₁ ^b which are electrophoretically distinguishable from one another by their Rf values 0.36 and 0.42. About 94 percent of the soybean accessions had theTi ^a allele. Two accessions from Korea,P.I. 157440 andP.I. 196168, do not have theSBTI-A2 protein(ti). Two accessions, one from Pakistan and the other from Korea, were identified as having theTi ^c allele. Only the Korean and central Indian soybean populations have a high frequency for theTi ^b allele. Within Korea, the soybeans from those districts that lie closest to Japan have a high frequency for theTi ^b allele whereas the soybeans from those districts that lie closest to China have a low frequency for theTi ^b allele. TheTi ^b allele is not present in soybeans from the Philippines, Vietnam, Thailand, Malaysia, Burma, Nepal, Pakistan, and Afghanistan. Only 1 accession each from Taiwan and Indonesia have theTi ^b allele. TheSp ₁ ^a allele is not present in soybeans from Taiwan, Vietnam, Thailand, Malaysia, Indonesia, Burma, Pakistan and Afghanistan. The highest frequency for theSp1 ^a allele occurs in soybean germ plasm from northern India and Nepal. The soybeans from Asia (including Japan) were divided into 3 gene centers— primary, secondary, and tertiary—containing 7 germ plasm pools. Paths of dissemination of the soybean from China to the rest of Asia were developed based upon a combination of electrophoretic data and available historical, agronomic, and biogeographical literature.