Genetics of isozyme variants and linkage relationships among allozyme loci in 35 eastern white pine clones

Abstract

Megagametophyte tissue from seeds of 35 clones of Pinusstrobus L. were subjected to horizontal starch gel electrophoresis. The resulting gels were tested for activity of 10 enzyme systems. Isozymes observed were under control of at least 17 loci. Direct evidence, based on segregation of allozymes in megagametophytes of heterozygous clones, is presented for nine loci in five systems (LAP, GPI, GOT, PGM, and AP). Three polymorphic loci were detected for LAP. No genetic variation was detected for IDH, ADH, GLY-3-PD, GDH, or 6 PDG.Five pairs of linked loci were detected by chi-square analyses of joint segregation. Twenty-five of 36 possible two-locus combinations among 18 clones were evaluated. Recombination estimates suggest relatively strong linkage between LAP1-LAP2 and GPI2-GOT1; weaker linkage between LAP2-GPI2 (based on one clone only); and weak linkage between LAP2-AP1 and GOT3-AP1.