Genetic Analysis of DIA, GOT and PGI Isozyme Loci in Daucus carota L. ssp. sativas

Isozymes are useful biochemical markers in plant breeding. This paper presents the first results on the inheritance of three enzyme systems: diaphorase (DIA), glutamate oxalacetate transaminase (GOT) and phosphoglucoisomerase (PGI) from leaves of Daucus carota L. ssp. sativus and the linkage relationships among these isozyme loci, marked Dia, Got, and Pgi. Methods of extraction and electrophoresis are described. Segregation ratios indicated that the DIA system is controlled by three genes: Dia-1, Dia-2 and Dia-3, Dia-1 as invariant. Two codominant alleles and a null allele were found for Dia-2, and four codominant alleles for Dia-3-GOT isozymes are encoded by three genes; Got-1, Got-2 and Got-3. An active allele and a null allele were observed for Got-1, two codominant alleles for Got-2 and Got-3, respectively. PGI isozymes are controlled by a single gene, Pgi-1, with two codominant alleles. Altogether one invariant isozyme locus and six polymorphic loci are postulated. Test of joint segregation suggested a linkage of Dia-3 and Pgi-1. The recombination value is 0.04 ± 0.009.