Genetic analysis of 12 polymorphic isozyme loci in Taro, Colocasia esculenta (L.) Schott

Abstract

Using polyacrylamide gel electrophoresis find isoelectric focusing, we studied the genetic control of isozymes in nine enzyme systems of taro, Colocasia esculenta (L.) Schott; acid phosphatase (ACP), diaphorase (DIA), glutamate oxaloacetate transaminase (GOT), hexokinase (HEX), isocitrate dehydrogenase (IDH), phosphogluconate dehydrogenase (PGD), phosphoglucoisomerase (PGI), shikimate dehydrogenase (SKDH), and superoxide dismutase (SOD). Diploid taro accessions from Nepal and other Asian countries were either selfed or crossed, and isozyme band segregation was tested in their progeny. A total of 12 loci with two to three alleles were determined for isozymes in leaf tissue; six loci of Got-1, Got-5, Idh-1, Pgi-3, Sod-3 and Sod-4 encoded a dimeric enzyme, whereas Acp-4, Dia-2, Hex-2 and Skdh loci encoded a monomeric enzyme. Null alleles were observed in the three loci, Hex-2, Pgd-1 and Sod-2. The loci of GOT, IDH, PGI and SKDH have been reported in the wild taro from Bangladesh. These reported loci appear to be identical to those observed in this study except for the PGI locus, which was detected using a different electrophoresis method. Including the nine isozyme loci of alcohol dehydrogenase, esterase, leucine aminopeptidase and phosphoglucomutase we identified previously, a total of 46 alleles at 21 loci of 13 enzyme systems have become available for genetic analyses in taro.