THE GENETIC-BASIS OF ENZYMATIC VARIATION IN SALIX-EXIGUA

The genetic basis of enzymatic variation was investigated in Salix exi gua Nutt., a widespread North American willow species. Biochemical var iation of 26 enzyme systems in the parental clones and full-sib famili es of a 2 x 2 balanced factorial design was assayed, employing starch gel electrophoresis. Results suggested that 14 enzymes are encoded by multilocus systems, while 12 enzymes are under single gene control. A total of 51 structural genes were revealed. Genetic determinism studie s verified disomic inheritance, Mendelian genetic control and codomina nt allelic expression in 13 loci. In the other 38 cases putative loci were assigned. Segregation distortion was detected in Pgi-2 and Ppo-1. In general, Salix exigua seems to be functionally diploidized.