Solanums: Inheritance and Linkage Relationships

Journal 01 Heredity 1988;79:377-384; OI)~2-1503!88!$2.00 Horizontal starch gel electrophoresis was used to pertorm genetic analysis to confirm the inheritance of various isozyme loci and report on additional loci in diploid Solanum species. Aps-I, Dis-I, and Idh-1 were identified as new loci, and tetrasomic seg­ regati on was reported at the tetraploid level for Mdh-2. Of 15 loci stu died, d Istarted segregatIons were observed in five diploid test crosses involving the Got-I, Idh-1, Pgi1, an d A dh-1 Ioc i. In these ca ses, fou r of the five pa rents were 01 inte rs pec ific originj the family segregating for Adh-1 was the exception. Utilizing various clones and interspecific combinations between S. phureja, S. tuberosum, and S. chacoense, further test crosses were made to determine linkage relationships between these isozyme loci and the yellow tuber flesh gene (Y). Two linkages were detected among these markers. Estimates of the Idh-1JSdh-1 linkage ranged from 10.4 map unIts (m.u.) to 36.8 m.u., whereas a tight linkage was confirmed lor Pnc-2!Prx.-3 (0.6 m.u.). Comparing putative homologous loci for the Idh-I!Sdh-I linkage implies some con­ servation sInce the divergence of Lycoperison, So/anum, and, to a degree, Capsicum. As a result of codominant ex.pression, these isozyme markers provide new oppor­ tunities for further genetic studies of tuber-bearing Solanums.