THE GENETIC-BASIS OF ENZYMATIC VARIATION IN SALIX-EXIGUA

The genetic basis of enzymatic variation was investigated in Salix exigua Nutt., a widespread North American willow species. Biochemical variation of 26 enzyme systems in the parental clones and full-sib families 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 studies verified disomic inheritance, Mendelian genetic control and codominant 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.